Histo Exam 2

Front 1

characteristics of blood

Back 1

alkaline (pH = 7.4), accounts for approx. 7% of the total body weight, total volume = 5L

Front 2

plasma

Back 2

yellowish fluid in which cells, platelets, organic compounds and electrolytes are suspended, major component is water (90%), proteins (9%)

Front 3

serum

Back 3

is the remaining fluid when the organic and inorganic components leave the plasma, straw colored

Front 4

formed elements

Back 4

are said to be the cellular composition of blood cells, RBCs, WBCs and platelets

Front 5

what happens if a centrifuge is taken and spins the blood?

Back 5

from bottom to top the layers are:
1. red layer: made up of erythrocytes (RBCs), 44% of blood
2. buffy coat layer: made up of leukocytes (WBCs) and platelelets (thrombocytes), 1% of blood
3. plasma: 55% of blood

Front 6

how is oxygen and carbon dioxide carried around in the blood

Back 6

O2 is carried by RBCs by hemoglobin and CO2 is carried by both hemoglobin and plasma (as bicarbonate)

Front 7

coagulation

Back 7

a protective mechanism that stops its flow in case of damage to the vascular tree, mediated by platelets and blood borne factors that transform blood from a sol to a gel state, ex: heparin

Front 8

hematocrit

Back 8

the total red blood cell volume

Front 9

hemopoiesis (hematopoiesis)

Back 9

the process of blood cell formation from established blood cell precursors

Front 10

stain preparations

Back 10

methylene blue stains acidic components blue and eosin stains alkaline components pink, azures stain components a reddish blue

Front 11

Geimsa vs. Wright stain

Back 11

Geimsa-pink
Wright-purple/blue

Front 12

albumin

Back 12

maintains colloid osmotic pressure and transports certain insoluble metabolites, maintains normal blood and interstitial fluid volumes

Front 13

alpha and beta globulins

Back 13

transport metal ions, preotein-bound lipids and lipid-soluble vitamins

Front 14

gamma globulin

Back 14

antibodies of immune defense

Front 15

clotting proteins (prothrombin, fibrinogen, accelerator globulin)

Back 15

formation of fibrin threads

Front 16

complement proteins (C1-C9)

Back 16

destruction of microorganisms and initiation of inflammation

Front 17

chylomicrons

Back 17

transport of triglycerides to liver

Front 18

very-low-density lipoproteins (VLDL)

Back 18

transport of triglycerides from liver to body cells

Front 19

low-density lipoprotein (LDL)

Back 19

transport of cholesterol from liver to body cells

Front 20

extracellular fluid

Back 20

composed of electrolytes and small molecules similar to that in plasma, the fluid component of blood that leaves the capillaries and small venules to connective tissue spaces, conc. of proteins is lower than that in plasma

Front 21

erythrocytes

Back 21

biconcave disks made in bone marrow, a bag of red oxygen carrying hemoglobin, lose all their organelles, including the nucleus, when they mature, smallest and numerous cells of blood, have an average lifespan of 120 days, when they reach this age put an oligosaccharide marker detected by macrophages for destruction

Front 22

carbonic anhydrase

Back 22

found in erythrocytes, facilitates the formation of carbonic acid from CO2 and H2O, as HCO3-, CO2 is transport to the lungs

Front 23

band 3 and CO2 transfer

Back 23

mediates the ability of bicarbonate to cross the erythrocyte cell membrane, it is a couple anion transporter that exchanges intracellular bicarbonate for extracellular Cl- (this shift is called the chloride shift), band 3 can also act as an anchoring site for ankyrin and band 4.1

Front 24

things that can affect RBC/volume in people

Back 24

being male and higher altitudes leads to higher RBC/volume

Front 25

hemoglobin

Back 25

a large protein composed of 4 polypeptide chains, each of which is covalently bound to a heme group

Front 26

heme group of hemoglobin

Back 26

binds iron, is bound within a hydrophobic depression, protect the iron from being oxidized while permitting the binding of oxygen to it (relaxed [R-] Hb), when O2 is released the place where it was held is occupied by 2,3 diphosphoglycerate (taut [T-] Hb)

Front 27

fetal hemoglobin (HbF)

Back 27

composed of two alpha chains and two gamma chains, replaced shortly after birth by adult hemoglobin (HbA)

Front 28

red blood cell membrane

Back 28

composed of about 50% protein, 40% lipids, and 10% carbs

Front 29

proteins of the RBC membrane

Back 29

glycophorin, ion channels and band 3

Front 30

band 4.1 proteins

Back 30

act as an anchoring site for spectrin, band 3 and glycophorins

Front 31

what anchors the cytoskeleton of RBC membrane

Back 31

ankyrin, band 3 and band 4.1 anchro the cytoskeleton composed of spectrin, actin and adducing, helps maintain the biconcave shape

Front 32

CO poisoning

Back 32

CO binds to Hb with a higher affinity than O2, when reach tissues, it will not release O2

Front 33

thalassemia

Back 33

marked by decreased synthesis of one or more hemoglobin chains, leads to high presence of HbF

Front 34

sickle cell anemia

Back 34

result of a point mutation at a single locus of the beta chain, forms HbS, when the O2 tension is reduced (during exercise), the cells become sickle shaped which are more fragile, less pliant and more prone to hemolysis

Front 35

hereditary spherocytosis

Back 35

caused by synthesis of an abnormal spectrin that exhibits defective binding to band 4.1, leads to more fragile patients and transport less oxygen, leads to spherocytes that are destroyed in the spleen leading to anemia

Front 36

elliptocytic RBCs

Back 36

deficiency of glycophorin C leads to these cells, has no associated anemia, just less capable of deformation

Front 37

A and B antigens on RBC membrane

Back 37

are carbohydrate antigen chains, determine the four blood groups

Front 38

Rh groups

Back 38

comprises more than two dozen antigens, C, D, and E Rh antigen are present in Rh+ individuals

Front 39

erythroblastosis fetalis

Back 39

occurs in an Rh- mother who gives birth to her second Rh+ baby, when the antibodies attack the erythrocytes of the fetus, could be potentially deadly

Front 40

leukocytes

Back 40

WBCs classified into granulocytes and agranulocytes (both contain lysosomes), only about 6500-10000 WBC/mm^3, generally defend the body against foreign substances

Front 41

diapedesis

Back 41

occurs when leukocytes reach their destination and leave the bloodstream by migrating between the endothelial cells of the blood vessels and enter the connective tissue spaces

Front 42

granulocytes

Back 42

neutrophils, eosinophils and basophils

Front 43

agranuloctyes

Back 43

leukocytes and monocytes

Front 44

neurtrophils (AKA polymorphonuclear leukocytes)

Back 44

compose most of the WBC population, avid phagocytes destroying bacteria that invade connective tissue spaces, multilobed nucleus (# INC with age)

Front 45

types of granules in neutrophils

Back 45

1. small specific-contain various enzymes and pharmacological agents that aid in its antimicrobial functions, appear oblong
2. large azurophilic-are lysosomes containing acid hydrolases
3. tertiary-contain gelatinase and cathepsins as well as glycoproteins that are inserted into the plasmalemma

Front 46

role of IL-1 and TNF on neutrophil function

Back 46

induce the endothelial cells to express intercellular adhesion molecules (ICAM) to which the integrin bolecules of neutrophils bind, allows for the neutrophils to stop migrating and enter the connective tissue

Front 47

how do neurtrophils function

Back 47

they destroy the microorganisms by phagocytosis and by the release of hydrolytic enzymes (and respiratory burst)

Front 48

sequence of events for neutrophil activated inflammatory response

Back 48

1. binding of neutrophil chemotacitc agents that facilitate the release of tertiary granules to the extracellular matrix
2. gelatinase degrades the basal lamina, facilitating neutrophil migration
3. release of the other granules to attack the microorganism
4. phagocytosis of microorganism (becomes a phagosome), use either complement or antigen on bacteria for recognition
5. kill bacteria through action of enzymes and formation of superoxide -> hydrogen peroxide -> hypochlorous acid with NADPH oxidase
6. release of azurophilic granules into the extracellular matrix, also degradation of hydrogen peroxide by catalse and glutathione peroxidase
7. neutrophils die themselves forming pus
8. synthesize leukotrienes aiding the inflammatory process

Front 49

function of neutrophils

Back 49

phagocytose and destroy bacteria by using the contents of their various granules, manufacture and release leukotrienes and initate the inflammatory response, adhere to selectin molecules on postcapillary venules, allows the cell to roll along the vessel’s endothelial lining

Front 50

hereditary deficiency of NADPH oxidase

Back 50

leads to persistent bacterial infections because they lack a respiratory burst response to them, cannot generate superoxide, hydrogen peroxide and hypochlorous acid

Front 51

eosinophils

Back 51

phagocytose antigen-antibody complexes and kill parasitic invaders, less than 4% of WBC, cell membrane has receptors for IgG, IgE and complement, have sausage shaped, bilobed nuclei, IL-5 causes their proliferation

Front 52

types of granules in eosinophiles

Back 52

1. specific-has an electron dense center internum and a less dense externum
a. internum contains major basic protein, eosinophilc cationic protein and eosinophil derived nuerotoxin
2. azurophilic granules-nonspecific, lysosomes containing hydrolytic enzymes similar to the ones in neutrophils, function in the destruction of parasitic worms

Front 53

eosinophil functions

Back 53

help to eliminate antibody-antigen complexes and parasitic worms
1. bind histamine, leukotiriens and eosinophil chemotactic factor to migrate to allergic site, inflammatory site or parasitic worm invasion, respectively
2. degranulate on the worms killing them through superoxides and hydrogen peroxides
3. release substances that inactivate the pharmacological initiators of the inflammatory response (histamine and leukotriene C)
4. engulf antigen-antibody complexes passing into the endosomal compartment

Front 54

basophils

Back 54

similar to mast cells in function, less than 1% of total leukocyte population, have an S-shaped nucleus, have IgE receptors (FceRI)

Front 55

basophil granules

Back 55

1. specific granules-stain dark blue, contain heparin, histamine, eosinophil chemotactic factor, neutrophil chemotactic factor and peroxidase
2. azurophilic-lysosomes which contain enzymes similar to those of neutrophils

Front 56

basophil function

Back 56

function as initiatiors of the inflammatory response, steps include
1. binding of antigen to the IgE, cause release of specific granules
2. phospholipase A generates arachidonic acid residues which activate the release of chemical fators that mediate the inflammatory response
3. histamine relase which causes vasodilation, smooth muscle contraction and leakiness of blood vessels
4. leukotriene release having the same effects of histamine but slower, also activate leukocytes to migrate to the site of antigenic challenge

Front 57

anaphylactic shock

Back 57

occurs in certain hyperallergic individuals when exposed to a second time to the same allergen, leads to increased smooth muscle constriction, DEC blood volume and widespread vasodilation

Front 58

monocytes

Back 58

largest of the circulating blood cells, enter the connective tissue spaces where they are known as macrophages, 3-8% of WBC, have large, acentric kidney shaped nucleus, stay in circulation only a few days

Front 59

function of monocytes/macrophages

Back 59

phagocytose unwanted particular matter (dead and defunct cells, bacteria), produce cytokines that are required for the inflammatory and immune responses and present epitopes to T lymphocytes, members of the mononuclear phagocyte system, can form large foreign-body giant cells to phagocytose large foreign particulate matter

Front 60

purpose of cytokine production

Back 60

activate the inflammatory response as well as the proliferation and maturation of other cells

Front 61

lymphocytes

Back 61

are agranulocytes and form the second largest population of white blood cells, constitue 20-25% of WBCs, nucleus occupies most of the cell

Front 62

subdivisions of lymphocytes

Back 62

1. B cells (15%), enter bone marrow to be immunologically competent
2. T cells (80%), migrate to the cortex of the thymus to be immunologically competent
3. null cells (5%)
morphologically indistinguishable but recognized by immunocytochemically by the difference in their surface markers

Front 63

B cell function

Back 63

responsible for the humorally mediated immune response, they differentiate into plasma cells which produce antibodies against antigens

Front 64

T cell function

Back 64

responsible for the cellularly mediated immune system, can differentiate into cytotoxic T cells (CTLs; T killer cells, contact and kill foreign cells), T helper cells (initiation and development of immune response cells) and T regulatory cells (suppression of immune response cells)

Front 65

clone of lymphocytes

Back 65

mature lymphocytes mature and divide and form a group of identical cells called clones, all members of a particular clone an recognize and respond to the same antigen

Front 66

memory cells

Back 66

B and T cells proliferate into these when exposed to a specific antigen, do not participate in the immune response but remain as part of the clone with an immunological memory, ready to undergo cell division and mount a response

Front 67

effector cells

Back 67

B and T cells proliferate into these when exposed to a specific antigen, classified as B cells and T cells (and their subtypes), perform lymphocyte immune function (eliminate antigens)

Front 68

null cells

Back 68

composed of stem cells (which give rise to all of the formed elements of blood) and natural killer (NK) cells (which can kill some foreing and virally altered cells without the influence of the thymus or T cell)

Front 69

platelets

Back 69

thromboplastids, small, disk shaped non-nucleated cell fragments derived from megakaryocytes in the bone marrow, display a peripheral clear region (hyalomere, house the tubules) and a central darker region (granulomere, house the granules)

Front 70

platelet tubules and granules

Back 70

possess three types of granules (alpha, delta, lambda) as well as two tubular systems (dense and surface opening)
1. surface opening system-coiled, forming a labyrinthine complex within the platelet, communicates with the outside, increases platelet surface area by a factor of 7 or 8, hyalomere, expedites rapid uptake and release of molecules from activated platelets
2. dense tubular system-hyalomere, sequesters calcium ions to prevent platelet stickiness

Front 71

different types of platelet granules

Back 71

1. alpha-contained factors facilitate vessel repair, platelet aggregation and coagulation of blood
2. delta-contained factors facilitate platelet aggregation and adhesion, as well as vasoconstriction
3. lambda-aid clot resorption

Front 72

microtubules, actin and myosin and platelets

Back 72

microtubules assist in maintaining their discoid morphology while actin and myosin form a contractile apparatus

Front 73

platelet function

Back 73

function in limiting hemorrhage to the endothelial lining of the blood vessel in case of injury, if endothelial lining is disrupted platelets become activated, release the contents of their granules, adhere to the damaged region (platelet adhesion) and adhere to each other (platelet aggregation)

Front 74

steps in platelet function

Back 74

1. intact endothelium produces prostcyclins and NO which inhibit platelet aggregation, also block coagulation through thrombomodulin and heparin
2. injured endothelial cells stop production of above factors and release von Wille brand factor, tissue thromboplastin and endothelin (a vasoconstrictor that reduces the loss of blood)
3. platelets adhere to subendothelial collagen, release granules and adhere to one another (platelet activation)
4. release ADP and thrombospondin makes platelets sticky
5. arachidonic acid is converted to thromboxane A2 (vasoconstrictor and platelet activator)
6. aggregated platelets act as a plug, express platelet factor 3 (provide a phospholipid surface for the proper assembly of the coagulation factor (thrombin)
7. thromboplastin acts on prothrombin to form thrombin (enzyme that facilitates platelet aggregation), in the presence of Ca2+ also converts fibrinogen to fibrin
8. fibrin polymerizes to form a reticulum of clot which entangles platelets, erythrocytes and leukocytes into a blood clot (thrombus) (erythrocytes facilitate platelet activation while neurtrophils and endothelial cells limit both platelet activation and thrombus size
9. actin and myosin form thin and thick filaments which contract shrinking the size of the clot pulling the edges of the damaged vessel closer together
10. when the vessel is repaired the endothelial cells release plasminogen activators which convert plasminogen to plasmin (initiates lysis of the thrombus)

Front 75

bone marrow

Back 75

a gelatinous, vascular connective tissue located in the marrow cavity, is richly endowed with cells that are responsible for hemopoiesis (from the 5th month of prenatal life until the person dies), constitutes about 5% of the total body weight, maturation of B cells and initial maturation of the T lymphocytes

Front 76

red bone marrow

Back 76

marrow of the new born, has a great number of erythrocytes, by age 20, the diaphyses of long bone house only yellow marrow

Front 77

yellow bone marrow

Back 77

marrow of the adolescent and adult (after age 20), accumulation of large quantities of fat and the absence of hemopoiesis in the shafts of these bones

Front 78

sinusoids

Back 78

receive blood from the centrally directed branches, drain into a central longitudinal vein which is drained by veins leaving the bone via the nutrient canal

Front 79

vascular compartment of bone marrow

Back 79

composed of the arteries, veins and sinusoids

Front 80

islands of hemopoietic cells

Back 80

fill the intervening spaces, pleomorphic, merge with each other forming the hemopoietic compartment

Front 81

reticular fibers and adventitial reticular cells

Back 81

line the sinusoids, form connections with other similar processes of other adventitial reticular cells to form hemopoietic cords (islands), adventitial reticular cells may accumulate fat and look like adipose cells (eventually turn red marrow into yellow marrow)

Front 82

hemopoietic cords (islands)

Back 82

composed of blood cells in various stages of maturation as well as macrophages (responsible for destroying the erythrocyte precursors, malformed cells and excess cytoplasm)

Front 83

thromboembolism

Back 83

most common type of embolism, clots break free and circulate in the bloodstream until they reach a vessel whose lumen is too small to accommodate them

Front 84

saddle embolus

Back 84

a clot that is large enough to occlude the bifurcation of the pulmonary artery, can result in sudden, unexpected death

Front 85

myocardial infarct

Back 85

may occur if a clot obstructs branches of the coronary artery

Front 86

vitamin K

Back 86

required by the liver as a cofactor in the synthesis of clotting factors VII, IX, and X and prothrombin, results in partial or complete dysfunction of the clotting process

Front 87

classic hemophilia

Back 87

factor VII deficiency, a recessive hereditary trait transmitted by mother to their male children, affected persons are likely to bleed after trauma

Front 88

thrombocytopenia

Back 88

the blood level of platelets is decreased, bleeding is common and forms purplish splotches on the skin, believed to be an autoimmune disease, antibodies thought to destroy the platelets

Front 89

leukemia

Back 89

adventitial reticular cells may lose their lipids and DEC in size, transforming yellow marrow to red marrow, thus making more space available for hemopoiesis

Front 90

prenatal hemopoiesis

Back 90

subdivided into four phases, mesoblastic, hepatic, splenic and myeloid

Front 91

mesoblastic phase

Back 91

beginning of blood cell formation, begins at 2 weeks in the mesoderm of the yolk sac where mesenchymal cells aggregate into clusters known as blood islands, peripheral cells form the vessel wall and the remaining cells become erythroblasts (which differentiate into nucleated erythrocytes)

Front 92

hepatic phase

Back 92

replaces the mesoblastic phase by the 6th week of gestation, erythrocytes still have nuclei and leukocytes appear by the 8th week

Front 93

splenic phase

Back 93

begins during the second trimester and both hepatic and splenic phases continue until the end of gestation

Front 94

myeloid phase

Back 94

when hemopoieses beings in the bone marrow by the end of the second trimester, liver and spleen may revert to blood formation if need arises

Front 95

postnatal hemopoiesis

Back 95

occurs almost exclusively in bone marrow

Front 96

pluripotential hemopoietic stem cells (PHSCs)

Back 96

give rise to all blood cells, account for about 0.1% of the nucleated cell population of bone marrow, usually amitotic but can undergo bursts of cell division

Front 97

multipotential hemopoietic stem cells (MHSCs)

Back 97

come from PHSCs, two types (colony-forming unit-lymphocyte (CFU-Ly) and colony forming unit-granulocyte, erythrocyte, monocyte, megakaryocte (CFU-GEMM) cells), give rise to various progenitor cells, resemble lymphocytes and constitute a small fraction of the null-cell population, each precursor cell has a unipotential CFU as its predecessor

Front 98

CFU-GEMM

Back 98

predecessors of the myeloid cell lines (granulocytes, erythrocytes, monocytes and platelets)

Front 99

CFU-Ly

Back 99

predecessors of the lymphoid cell lines (T cells and B cells)

Front 100

growth factors and stem cells and there effect on Stem cells

Back 100

help change it from G0 to G1 phase

Front 101

homeobox genes and stem cells

Back 101

may be active in the differentiation of the early stages of hemopoietic cells

Front 102

progenitor cells

Back 102

also resemble small lymphocytes but are unipotential (commited to forming a single cell line, such as eosinophils), limited capacity for self-renewal

Front 103

precursor cells

Back 103

arise from progenitor cells and are incapable of self-renewal, they have specific morphological characteristics that permit them to be recognized as the first cell of a particular cell line, undergo cell division and differentiation to give rise to a clone of mature cells,

Front 104

reticulocytes

Back 104

the immediate precursor to erythrocytes

Front 105

stab cells

Back 105

immediate precursor to the granulocytes

Front 106

how do growth factors and interleukins act on specific stem cells

Back 106

induce rapid mitosis, differentiation, or both, most are glycoproteins

Front 107

routes used to deliver growth factors to their target cells

Back 107

1. transport via the bloodstream (endocrine hormones)
2. secretion by stromal cells of the bone marrow near the hemopoietic cells (as paracrine hormones)
3. direct cell-to-cell contact (as surface signaling molecules)

Front 108

which factors simulate proliferation of pluripotential and multipotential stem cells

Back 108

steel factor (stem cell factor), granulocyte-macrophage colong-stimulating factor (GM-CSF) and IL-3 and IL-7

Front 109

which factors are responsible for the mobilization and differentiation of these cells into unipotential progenitor cells?

Back 109

cytokines G-CSF, M-CSF, and all the other interleukins

Front 110

colony stimulating factors (CSF)

Back 110

also responsible for the stimulation of cell division and for the differentiation of unipotential cells of the granulocytic and monocytic series

Front 111

erythropoietin

Back 111

activates cells of the erythrocytic series

Front 112

thrombopoietin

Back 112

stimulates platelet production

Front 113

steel factor (stem cell factor)

Back 113

produced by stromal cells, needed for hemopoieses to occur, why postnatal blood cell formation is restricted to the bone marrow

Front 114

apoptosis and hemopoesis

Back 114

hemopoietic cells are programmed to die by undergoing apoptosis unless they come into contact with growth factors

Front 115

secondary polycythemia

Back 115

increased secretion of erythropoietin, increase in the total number of RBCs in the blood, INC viscosity, reducing its flow rate and impeding circulation, usually caused by tumors

Front 116

erythropoiesis

Back 116

the formation of red blood cells, under the control of several cytokines, namely steel factor, IL-3, IL-9, GM-CSF and erythropoietin

Front 117

what are the unipotential progenitor cells responsible for erythropoiesis

Back 117

burst-forming units-erythrocytes (BFU-E) and colony-forming units erythrocyte (CFU-E)

Front 118

erythropoietin

Back 118

produced by the kidney if the circulating red blood cell level is low, induces a burst of mitotic activity forming a large number of CFU-E, forms proerythroblast

Front 119

proerythroblasts

Back 119

form spherical clusters around macrophages which phagocytose extruded nuclei and excess or deformed erythrocytes

Front 120

iron-deficiency anemia

Back 120

most common form of anemia resulting from nutritional deficiency, affects about 10% of the U.S. population, caused by malabsorption or chronic blood loss, leads to smaller erythrocytes, symptoms include weakness, tiredness and lack of energy

Front 121

granulocytopoiesis

Back 121

the formation of granulocytes, under the influence of several cytokines, namely G-SF, GM CSF and ILs

Front 122

CFU-GEMM

Back 122

gives rise to each of the unipotential stem cells of the granulocytes (CFU-G, M, Ba or Eo)

Front 123

myeloblasts

Back 123

precursors of all three types of granulocytes, cannot be differentiated from one another

Front 124

myelocyte step of granulocytopoiesis

Back 124

this step is where specific granules are present and the three granulocyte lines may be recognized

Front 125

migration of mature neutrophils

Back 125

leave the hemopoietic cords by piercing the endothelial cells lining the sinusoids rather than by migrating between them, they then marginate (adhere to the endothelial cells and remain there)

Front 126

acute myeloblastic leukemia

Back 126

results from uncontrolled mitosis of a transformed stem cell whose progeny do not differentiate into mature cells, may involve CFU-GM, CFU-Eo or CFU-Ba

Front 127

monocytopoiesis

Back 127

share their bipotential cells with neutrophils (CFU-GM -> CFU-G and CFU-M)

Front 128

platelet formation

Back 128

under the control of thrombopoietin, induces the development and proliferation of giant cells known as megakaryoblasts, CFU-Meg gives rise to megakaryoblast, undergo endomitosis (cell does not divide and becomes polyploidy)

Front 129

megakaryocytes

Back 129

come from megakaryoblasts, located next to sinusoids, can give rise to several thousand platelets

Front 130

lymphopoiesis

Back 130

pluripotential hemopoietic stem cells give rise to the myeloid series of cells via CFU-GEMM cells as well as to the lymphoid series of cells via CFU-Ly cells

Front 131

CFU-Ly

Back 131

give rise to CFU-LyB and CFU-LyT

Front 132

CFU-LyB

Back 132

divides multiple times to give rise to immunocompetent B lymphocytes, express specific surface markers including antibodies

Front 133

CFU-LyT

Back 133

undergo mitosis, forming immunoincompetent T cells, travel to the cortex of the thymus where they proliferate, mature and begin to express cell surface markers (become immunocompetent)

Front 134

migration of B and T cells

Back 134

proceed to lymphoid organs (such as the spleen and lymph nodes) where they form clones

Front 135

arteries vs. veins

Back 135

arteries have thicker walls than veins (because they are more high pressure) but are smaller in diameter than veins, arteries are round and usually have no blood in their lumina

Front 136

wall layers of blood vessels

Back 136

from superficial to deep
1. tunica intima-composed of a single layer of flattened, squamous endothelial cells, which form a tube lining the lumen for the vessel and underlying subendothelial connective tissue
2. tunica media-composed mostly of smooth muscle cells oriented concentrically around the lumen
3. tunica adventita-composed mainly of fibroelastic connective tissue arranged longitudinally

Front 137

internal elastic lamina

Back 137

a thin band of elastic fibers that is well developed in medium sized arteries, separates the tunica intima from the tunic media, found deep to the subendothelial layer, well developed in muscular arteries, fenestrated so allows for diffusion of goods through it

Front 138

external elastic lamina

Back 138

another band of elastic fibers, separates the tunica media from the tunica adventitia, is not distinguishable in all arteries, not present in capillaries and postcapillary venules

Front 139

vasa vasorum

Back 139

allow for deeper cells of the tunica media and tunica adventitia to still receive blood, furnish muscular wall of the larger blood vessels with a blood supply, small arteries that enter the vessel walls and branch profusely, more prevalent in veins than in arteries because venous blood supply contains less oxygen for the tissue

Front 140

tunica intima

Back 140

composed of a simple squamous epithelium and the subendothelial connective tissue, rest on a basal lamina and line the lumen, function also in secreting types II, IV and V collagens, lamin, endothelin, NO, and von Willebrand factor

Front 141

angiotensin converting enzyme and tunica intima

Back 141

ACE may be found as a membrane bound enzyme on the tunica intima, cleaves angiotensin I to angiotensin II

Front 142

subendothelial layer

Back 142

lies immediately beneath the endothelial cells, composed of loose connective tissue and a few scattered smooth muscle

Front 143

tunica media

Back 143

usually the thickest layer of the vessel wall, composed of helically disposed layers of smooth muscle

Front 144

tunica adventitia

Back 144

the outermost layer of the blood vessel wall, blends into the surrounding connective tissue, composed mostly of fibroblasts, type I collagen and longitudinally oriented elastic fibers

Front 145

what supplies smooth muscle cells of blood vessels

Back 145

a network of vasomotor nerves of the sympathetic component of the ANS, unmyelinated, postganglionic sympathetic nerves responsible for vasoconstriction, found more so on arteries than veins

Front 146

nerves of the smooth muscle cells seldom enter the tunica media, how do they innervate the muscle cells

Back 146

they release norepinephrine which diffuses inot the media and acts on smooth muscle cells nearby, the impulses are then propagated throughout all of the smooth muscle cells via their gap junctions to allow for contraction of the entire smooth muscle cell layer

Front 147

classification of arteries

Back 147

from largest to smallest they are: elastic arteries (conducting arteries), muscular arteries (distributing arteries) and arterioles

Front 148

elastic arteries

Back 148

aorta and the branches originating from the aortic arch, the common iliac arteries and the pulmonary trunk, characteristics include:
1. have an abundance of elastin, especially in the TM
2. presence of IEM and EEM
3. releases factors (von Willebrand factor) from Weibel-Palade bodies that facilitate blood clotting (stored only in arteries)
4. has fenestrated membranes in the TM alternating with smooth muscle (which are less abundant here than in other arteries)
5. thin tunica adventitia composed of loose fibroelastic connective tissue
6. abundance of vasa vasorum

Front 149

muscular arteries

Back 149

contain most vessels arising from the aorta except the ones identified as elastic arteries (most of the named arteries), charateristics include
1. thick TM composed mostly of smooth muscle cells (as many as 40 layers-4layers)
2. thinner TI compared to elastic arteries, but the subendothelial layer contains some smooth muscle cells
3. has prominent, wavy IEM and EEM which are found in only some of the larger muscular arteries
4. TA composed of elastic fibers, collagen fibers and ground substance
5. vasa vasorum present

Front 150

bifid internal elastic lamina (membrane)

Back 150

occurs when the internal elastic lamina is duplicate

Front 151

aneurysm

Back 151

a sac like dilation of the wall of an artery, results from weakness in the vessel wall (can be due to atherosclerosis, syphilis and CT disorders), normally elastic fibers are replaced by collagen fibers

Front 152

arterioles

Back 152

arteries with a diameter of less than 0.1 mm, width of wall = diameter of lumen, characteristics include:
1. thin TI
2. thin fenestrated IEM present in only the largest arterioles, but absent in small and terminal arterioles, absent EEM
3. thin TM that can consist from 1-3 layers of smooth muscle
4. scant TA composed of fibroelastic connective tissue housing a few fibroblasts

Front 153

metarterioles

Back 153

arteries that supply blood to the capillary bed, have smooth muscles that are spaced apart not continuous like arterioles, can act as a sphincter controlling blood flow into the capillary bed

Front 154

types of specialized sensory structures located in the major arteries

Back 154

carotid sinuses, carotid bodies, and aortic bodies, nerve endings in these structures monitor blood pressure and blood composition, provides inputs to the brain for controlling heartbeat, respiration and blood pressure

Front 155

carotid sinus

Back 155

a baroreceptor (perceives changes in blood pressure), located in the region of the internal carotid artery just distal to the bifurcation of the common carotid artery, thicker TA, thinner TM which allows it to become distended during INC bp, signals tell brain to trigger adjustment in vasoconstriction, innervated by CN IX (glosopharyngeal)

Front 156

carotid body

Back 156

functions as a chemoreceptor, monitoring changes in O2 and CO2 levels as well as hydrogen ion concentration, located at the birfucation of the common carotid artery, is a small oval structure, contains glomus (type I) cells and sheath (type II) cells, contain catecholamines, innervated by CN IX and vagus

Front 157

glomus cells

Back 157

have dense-cored vesicles, contact other glomus cells and endothelial cells, large nucleus

Front 158

sheath cells

Back 158

more complex and have long processes that ensheath the processes of the glomus cells, lack dense-cored vesicles, irregular nuclei

Front 159

aortic bodies

Back 159

located on the arch of the aorta, similar in structure and function to the carotid bodies

Front 160

regulation of arterial blood pressure

Back 160

by the vasomotor center in the brain which controls vasomotor tone (the constant state of contraction of the vessel walls mediated by vasoconstriction and vasodilation)

Front 161

vasoconstriction vs. vasodilation

Back 161

vasoconstriction is controlled by the sympathetic nervous system and vasodilation is controlled by the parasympathetic system

Front 162

how does vasodilation occur

Back 162

acetylcholine is released which initiates release of NO from the endothelium which diffuse into the smooth muscle cells which activates cGMP system resulting in relaxation of the muscle cells

Front 163

rennin and control of bp

Back 163

rennin relased by kidneys when bp is low, this cleaves angiotensiogen into angiotensin I which is converted into angiotensin II by ACE, angiotensin II is a vasoconstrictor, ADH (vasopressin) also acts as a vasoconstrictor

Front 164

arteriosclerosis and atherosclerosis

Back 164

arteriosclerosis is a general term describing any hardening of medium and large veins while atherosclerosis is hardening due to plaque, so atherosclerosis is a type of arteriosclerosis

Front 165

structure of capillaries

Back 165

composed of a single layer of endothelial cells, smallest blood vessels, long axis of endothelial layer lie in the same direction as blood flow, can contain filaments composed of desmin, vimentin or both, these filaments provide structural support ot the endothelial cells, external surface covered by a basal lamina, endothelial cells joined by tight junctions

Front 166

types of capillaries

Back 166

continuous, festrated and sinusoidal

Front 167

marginal fold

Back 167

a fold that projects into the lumen and characterizes endothelial cells that overlap which allow for

Front 168

pericytes

Back 168

located along the outside of the capillaries and small venules, have long processes that form gap junctions with the endothelial cells, responsible for the contractile process that regulates blood flow through the cappilaries, may differentiate into smooth muscle cells after injury

Front 169

continuous capillaries

Back 169

have no pores or fesestrae in their walls, present in muscle, nervous and connective tissues, prevent passage of many molecules and need carrier mediated transport to move glucose, nucleosides and purines

Front 170

fenestrated capillaries

Back 170

possess pores (fenestrae) in their walls that are covered by pore diaphragms, found in the pancreas, intestines and endocrine glands

Front 171

renal glomerulus

Back 171

fenestrated capillaries that lack diaphragms

Front 172

sinusoidal capillaries

Back 172

may possess discontinuous endothelial cells and basal lamina and contain may large fenestrae without diaphragms, enhancing exchange between blood and tissue, found in bone marrow, liver, spleen, lymphoid organs and certain endocrine organs, they conform to the shape of the structure they are found in, they do have an enlarged diameter

Front 173

anteriovenous anastomoses (AVA)

Back 173

are direct vascular connections between arterioles and venules that bypass the capillary bed, when they are closed blood goes into the capillaries, when they are open blood enters the AVA and goes straight to venules, important in thermoregulation and abundant on the skin

Front 174

glomera

Back 174

give blood supply to the nail beds and tips of the fingers and toes, it is a small organ that receives an arteriole

Front 175

central channel

Back 175

metarterioles form the proximal portion of a central channel and thoroughfare channels (no sphincters) form the distal portion of a central channel, thoroughfare channels drain the capillary bed and empty the blood into small venules of the venous system, when the sphincters on the metarterioles are contractred, then blood bypasses the capillary bed and heads straight into the venules

Front 176

pore systems of capillaries

Back 176

can be small pores or large pores, small pores are discontinuities while large pores are fenestrae and transport vesicles

Front 177

transcytosis

Back 177

transfer of water-soluble molecules from the adluminal plasmalemma to the abluminal plasmalemma, the material traverses the entire cell

Front 178

various methods across capillary endothelia

Back 178

1. endocytosis with the vesicle forming on the adluminal plasmalemma
2. vesicles from the golgi transport to the adluminal side and pick up substances through receptor mediated endocytosis
3. adluminal and abluminal vesicles fuse forming a transient fenestration through the entire cell layer

Front 179

endothelin I

Back 179

a vasoconstrictor, secreted by the capillary endothelial cells, keeps the smooth muscle contracted for long periods thus elevating bp

Front 180

veins

Back 180

outnumber arteries, have larger luminal diameters, 70% of total volume are in veins, collapsed walls because they are thinner and less elastic because the venous return is a low-pressure system, more pronounced connective tissue component but less developed muscular and elastic layer

Front 181

classification of veins

Back 181

small, medium and large veins

Front 182

venules

Back 182

similar to but larger than capillaries, larger venules possess smooth muscle cells instead of pericytes, thin endothelium, allow for transport as well because small venules’ walls are even more permeable than capillaries (leukocytes prefer to enter through here rather than capillaries)

Front 183

high endothelial venules

Back 183

endothelial cells of venules located in lymphoid organs that are cuboidal rather than squamous, function in lymphocyte recognition and segregation by type-specific receptors on their luminal surface

Front 184

small veins

Back 184

similar to venules but smooth muscle layer is continuous

Front 185

medium veins

Back 185

less than 1 cm in diameter, drain most of the body, characteristics include
1. TI that includes endothelium and its basal lamin and reticular fibers
2. elastic network surrounds the endothelium sometimes but do not form IEM
3. TM present with smooth muscle cells of the tunica media
4. TA is the thickest of the tunicas, composed of longitudinally arranged collagen bundles and elastic fibers as well as a few scattered smooth muscle cells

Front 186

large veins

Back 186

return venous blood directly to the heart from the extremities, head, liver and body wall, include the vena cavae and the pulmonary, portal, renal, internal jugular, iliac and azygos veins, characteristics
1. TI similar to medium veins but large veins have a thick subendothelial connective tissue layer containing fibroblasts and a network of elastic fibers
2. TM is absent in most large veins, except the pulmonary veins and superficial veins of the legs
3. well developed TA, contains many elastic fibers, collagen fibers and vasa vasorum, IVC has smooth muscle in TA

Front 187

valves of veins

Back 187

composed of two leaflets, each composed of a thin fold of the intima jutting out from the wall into the lumen, found in many medium valves that function to prevent the backflow of blood (especially where they have to fight the force of gravity

Front 188

varicose veins

Back 188

abnormally enlarged tortuous veins, results from loss of muscle tone, degeneration of vessel walls and valvular incompetence, may end in the lower end of the esophagus (esophageal varices) or at the terminus of the anal canal (hemorrhoids)

Front 189

layers of the heart wall

Back 189

endocardium, myocardium and epicardium

Front 190

endocardium

Back 190

a simple squamous epithelium and underlying sebendothelial connective tissue lines the lumen of the heart and connects it to the myocardium, continuous with the TI of the blood vessels

Front 191

rheumatic fever

Back 191

may lead to scarring of the valves stemming from the rheumatic fever epidose, develops because the valves cannot close or open properly, usually affects the mitral and aortic valves

Front 192

myocardium

Back 192

thick middle layer of the heart, composed of cardiac muscle cells

Front 193

purkinje fibers

Back 193

large, modified cardiac muscle cells, transmit impulses to the cardiac muscle cells located at the apex of the heart

Front 194

peptide secretion of cardiac muscle cells

Back 194

include atriopeptin, atrial natriuretic polypeptide, cardiodilatin and cardionatric, aid in fluid maintenance and electrolyte balance and decrease blood pressure

Front 195

epicardium

Back 195

represents the homologue of the TA in blood vessels, also called the visceral layer of the pericardium, composed of a simple squamous epithelium called mesothelium, subepicardial loose CT contains coronary vessels, nerves and ganglia

Front 196

pericarditis

Back 196

infection in the pericardial cavity, severely restricts the heart from beating properly because the space is obliterated by adhesions between the epicardium and the serous layer of the pericardium

Front 197

cardiac skeleton

Back 197

composed of dense connective tissue, provides a structural framework for the heart and attachment sites for the cardiac muscle
1. annuli fibrosi-formed around the base of the aorta, pulmonary artery and the AV orifices
2. trigonum fibrosum-formed primarily in the vicinity of the cuspal area of the aortic valve
3. septum membranaceum-consisting the upper portion of the IV septum

Front 198

ischemic coronary heart disease

Back 198

prevalent in older persons, related to atherosclerosis of the coronary vessels serving the myocardium, may lead to referred pain and pressure (angina pectoris)

Front 199

lymphatic vascular system

Back 199

consists of vessels that collect the excess interstitial (extracellular) fluid and return it to the cardiovascular system, found everywhere except CNS, epidermis, cartilage, bone, is an open system (no pump and no circulation of fluid) as opposed to the closed system of the cardiovascular system

Front 200

lymph drainage

Back 200

from lympathic capillaries (blind-ended tissues) -> lymphatic vessels -> one of the two lymphatic ducts (they form junctions at the internal jugular and subclavian veins)

Front 201

lymph nodes

Back 201

interposed along the paths of lymphatic vessls, lymph must pass through here to be filtered

Front 202

lymphatic capillaries

Back 202

composed of a single layer of attenuated endothelial cells with
1. an incomplete basal lamina
2. do not have fenestrations
3. do not make tight junctions with each other
4. are blind end vessels

Front 203

small and medium lymphatic vessels

Back 203

have closely spaced valves, large lymphatic vessels resemble small veins structurally except they have larger lumina and thinner walls

Front 204

lymphatic ducts

Back 204

similar to large veins, empty their contents into the great veins of the neck
1. TI composed of an endothelium and several layers of elastic and collagen fibers
2. TM there is a layer of condense elastic fibers that resembles an IEM, has both longitudinal and circular layers of smooth muscle
3. TA contains longitudinally oriented smooth muscle cells and collagen fibers
4. have small vessels that pierce the wall similar to vasa vasorum

Front 205

right lymphatic duct

Back 205

short, empties its contents into the venous system at the junction of the right internal jugular and subclavian veins, collects lymph from the upper right body

Front 206

thoracic duct

Back 206

larger and begins in the abdomen as the cisterna chili, ascends through the thorax and neck to empty its contents at the junction of the left internal jugular and subclavian veins, collects lymph from the rest of the body

Front 207

malignant tumor cells

Back 207

spread throughout the body by lymphatic vessels, when they reach a lymph node, they are slowed and multiply there, they then spread secondarily to different regions

Front 208

skin

Back 208

largest organ of the body, constitutes 16% of body weight, composed of an epidermis (ectodermal derived stratified squamous keratinized epithelium, and underlying dermis (mesoderm derived dense, irregular connective tissue), acts as the window to disease states: jaundice, cyanosis, measles and chicken poxes)

Front 209

functions of skin

Back 209

1. protection against injury, invasion and desiccation
2. regulation of body temperature and blood pressure
3. reception of sensations from the environment
4. excretion from sweat glands
5. absorption of UV radation for the synthesis of vita D

Front 210

epidermis

Back 210

regenerated every 30 days, keratinocytes divide at night, overlies projections of the dermis (dermal papillae) forming a series of epidermal ridges (fingerprints, dermatoglyphs, develop in the fetus and don’t change throughout life)

Front 211

hypodermis

Back 211

deep to the dermis, loose connective tissue containing varying amounts of fat, the superficial fascia, not part of the skin, thickness varies with nutritional statues, level of activity, body region and gender, loose CT and adipose tissue

Front 212

panniculus adiposus

Back 212

if the fat is really thick, fat that is deposited in the superficial fascia in people who are overnourished or live in cold weather environments

Front 213

keratinocytes

Back 213

make up most of the epidermis with continuous turnover, cell renewal (mitosis), differentiation (keratinization), cell death, exfoliation, arranged in five layers, on their way to the surface they differentiate and begin to accumulate keratin filaments

Front 214

five layers of the epidermis/keratinized system (from deep to superficial)

Back 214

1. stratum basale
2. stratum spinosum
3. stratum granulosom
4. stratum lucidum
5. stratum corneum

Front 215

thick skin

Back 215

covers the palms and soles, characterized by the presence of all five layers, lacks hair follicles, arrector pili muscles and sebaceous glands bud does possess sweat glands

Front 216

thin skin

Back 216

covers most of the remainder of the body, thin stratum corneum, lacks a definite stratum lucidum and granulosum, has hair follicles, arrector pili muscles, sebaceous glands and sweat glands

Front 217

stratum basale (germinativum)

Back 217

rest on basal lamina (basement membrane), keratinocytes divide continuously, kertinocytes possess desmosomes (cellular adhesion), hemidesmosomes (attachment to the basal lamina) and cytokeratin, cytokeratin increases as these cells approach the surface, also contains melanocytes and Merkel’s cells, consists of a single layer of cuboidal to low columnar cells containing basophilic cytoplasm and a large nucleus

Front 218

stratum spinosum

Back 218

several layers thick, tonofibirls (bundles of cytokeratin) + desmosomes = spiny processes characteristic of this layer -> prickle cells with intercellular bridges, keratinocytes in deeper layers are mitotically active, begin to produce keratohyalin granules, contain membrane coating granules of lipid (lamellar granules)

Front 219

Malpighian layer

Back 219

consist of both the stratum basale and spinosum, mitotically active layers

Front 220

tonofibrils

Back 220

groups of tonofilaments produced by keratinocytes that move superficially, cause the cytoplasm to become eosinophilic

Front 221

stratum granulosum

Back 221

contains some lamellar granules, membrane-less keratohyalin granules, and bundles of tonofilaments filaments (cytokeratin), contain membrane coated lamellar granules that fuse with the plasma membrane and released GAGs and phospholipids into the intercellular spaces, important in sealing deeper layers and water proofing, keratohyalin granules contain histidien and cystine rich proteins which bind the tonofilaments toegehter to form keratin, first step in keratinization (the conversion of granular cells to cornified cells), keratinization takes 2-6 hours, most superficial layer where cells still contain a nucleus

Front 222

stratum lucidum

Back 222

seen only in thick skin, acidophilc, contains immature keratin called eleidin but devoid of nuclei and organelles, clear, light staining region

Front 223

stratum corneum

Back 223

most superficial layer, dead, platelike, enucleated keratinocytes containing mature keratin, keratin birefringent scleroprotein of at least 6 polypeptides + tonofilaments, superficial layers called squames (horny cells) and sloughed off (dequamated)

Front 224

psoriasis

Back 224

accelerated kertinocyte mitosis in stratum basale and spinosum, turnover (one week instead of 4 weeks), leads to thickening of epidermis

Front 225

Langerhan’s Cells (dendritic cells)

Back 225

originate in the bone marrow, part of the MNP system, contains Birbeck’s granules (rodlike or racket shaped), antigen presenting cells, cells have cell surface antibody and compliment recetpros, capable of phagocytosis, located primarily in the stratum spinosum, oral, esophageal, rectal and vaginal epithelium as well as the thymus, thought to initiate allergic contact dermatitis reaction, are capable of mitosis but it is restricted

Front 226

merkel’s cells

Back 226

found in the stratum basale, derived from neural crest cells, possess desmosomes and tonofilaments, most numerous in thick skin, act as sensory mechanoreceptors, abundant in the fingertips, oral mucosa and base of hair follicles

Front 227

melanocytes

Back 227

derived from neural crest, in stratum basale, no desmosomes, first cell to arrive in the epidiermis

Front 228

melanosomes

Back 228

site of melanin granule synthesis, contain tyrosinase (an UV-sensitive enzyme involved in melanin synthesis and produced in the ER), tyrosinase turns tyrosine into melanin and is activated by UV light, no difference in the number of melanocytes per unit area in dark and light skinned races, rather differences in the rates of melanin synthesis, accumulation and degradation

Front 229

melanin

Back 229

contributes to skin, eye, hair color and freckles (patches of epidermal melanin), synthesized by melanocytes

Front 230

melanin function

Back 230

sun causes formation of highly reactive free radicals which is bad for dividing cells, melanin helps absorb some of the rays but the real protective effect is because melanin absorbs the free radicals

Front 231

fate of mature melanin granules

Back 231

1. mature granules move from Golgi into tips of melanocytes
2. melanin granules injected into keratinocytes of basale and spinosum by cytocrine secretion
3. most melanin in keratinocytes rather melanocytes
4. melanin granules accumulate over the nuclei of dividing keratinocytes, protecting the DNA from damaging effects of sun’s rays
5. eventually the melanin pigment is attacked and degraded by lysosomes of the keratinocyte (over a period of several days)

Front 232

Addison’s disease

Back 232

insufficient production of cortisol by the adrenal cortex so excess ACTH is produced, this leads to hyperpigmentation

Front 233

albinism

Back 233

is the absence of melanin production resulting from a genetic defect in tyrosinase synthesis, melanosomes present but the melanocytes fail to produce tyrosinase

Front 234

two effects of the sun

Back 234

photoaging and cancer, sunlight is needed for vitamin D homeostasis other than that no other benefit, effects of sun exposure are accumulative, 50% of lifetime exposure occurs prior to the age of 18

Front 235

sunburns/tans

Back 235

tanning is a sign of pathological damage to the skin, keratinocytes lose alignment, flatten, obtain nuclear inclusion, melansomal nuclear capping trying to protect DNA from UV radiation, melanocytes enlarge, INC in number and migrate to higher levels of epidermis, it affects immune properties of skin, affects Langerhans cells by reducing antigen-presenting capabilities, activates T suppressor networks

Front 236

dermal effects of sunburns and tans

Back 236

dermal changes in elastic tissue and collagen, fibers, leaky vasculature, increase in mast cells, actinic changes (those caused by UV radiation), leathery texture, wrinkling, sagging, blotchy discoloration

Front 237

basal cell carcinoma

Back 237

most common (75%), arises from the stratum basale, slow growing, diagnose early there is a high cure rate

Front 238

squamous cell carcinomas

Back 238

have a significant risk of metastatic spread, 20%, arises from stratum spinosum, usually appears in elderly, can grow rapidly (ulcerate), diagnose early there is a high cure rate, best documentation for INC risk with sun exposure

Front 239

melanoma

Back 239

5%, most dangerous of the three, usually appears as dark brown or black mole like lesions, any changes in moles appearance should be checked out, most common in upper back in men and legs in women, grows rapidly, metastasizes quickly

Front 240

ABCDs in diagnosing melanoma

Back 240

A- asymmetry
B- border irregularity
C- color-black or much darker than patient’s other moles (often with red, white or blue areas)
D- diameter > 6 mms

Front 241

dermis

Back 241

vascular dense, irregular CT, has types I and III collagen and elastic fibers derived from mesoderm, atriovenous shunts for temperature regulation, always thicker than epidermis

Front 242

papillary layer (superficial)

Back 242

dermal papillae interdigitate with the epidermal ridges, contain Meissner’s corpuscles (fine touch reeptors), type III collagen fibers and elastic fibers, type VII anchoring fibers binding epidermis to dermis

Front 243

reticular layer of the dermis

Back 243

follciles, sweat and sebaceous glands, dense irregular CT, elastic fibers and bundles of collagen fibers (mostly type I), pacinian corpuscles (pressure receptors) and ruffini corpuscles (temperature and pressure receptors)

Front 244

rete apparatus

Back 244

the interdigitation of the epidermal ridges with the dermal ridges

Front 245

eccrine sweat glands

Back 245

simple coiled, tubular gland, secretory units include the dark cells, clear cells and myoepithelial cells, ducts lined with stratified cuboidal epithelium (this modifies sweat by absorbing electrolytes, excreting ions, urea and lactic acid), unlimited distribution (merocrine secretion), responds to heat and nervous stress, purposes include (cooling/thermoregulation which is parasympathetic and excretion of urea and ammonia), emotional sweating is sympathetic, merocrine

Front 246

hyperhidrosis

Back 246

excessive sweating, primary is essential and idiopathetic, sweating of hands most distressing, treatment includes antiperspirants, iontophoresis, drugs and surgery for axillary

Front 247

dark cells (mucoid cells)

Back 247

line the lumen of the secretory unit and secrete a mucus-rich substance, shaped as an inverted cone with the larger end dumping into the lumen

Front 248

clear cells

Back 248

do not possess secretory granules, they release a watery secretion to the intercellular canaliculi where it mixes with the mucus secretion of the dark cells, shaped as a rightside up cone, with the larger end on the basal lamina, contain accumulations of glycogen

Front 249

myoepithelial cells

Back 249

surrounding the secretory portion of the eccrine sweat gland, contain actin and myosin, imparting a contractile ability to these cells, enveloped by the basal lamina

Front 250

duct of eccrine sweat glands

Back 250

composed of basal and luminal cells, highly coiled and traverses the dermis and epidermis on its way to the skin surface

Front 251

apocrine sweat glands

Back 251

include large specialized sweat glands in the axilla, areola of the nipple and the perianal region, glands of Moll in eyelids and ceruminous (wax) glands of the ear, represent vestigial scent glands, do not begin to function until puberty, response to hormonal influences, respond to emotional and sensory stimuli but not heat, larger than sweat glands, open into canals of the hair follicles just superficial to the entry of the sebaceous gland ducts (dermis), secretory cells are simple cuboidal to low columnar, have myoepithelial cells around the secretory units, innervated by the postsynaptic sympathetic nervous system, release their secretion by a merocrine process

Front 252

sebaceous glands

Back 252

empty into the neck of a hair follicle but can sometimes empty on the skin itself, are embedded in dermis over entire body other than palms and soles, most abundant on face, forehead and scalp, holocrine glands producing oily sebum makes hair shiny and flexible, skin supple and acne, mature sebaceous glands are present on the face by 6 months in utero, at birth sebaceous glands become inactive (until puberty -> androgens),

Front 253

acne

Back 253

thought that the increase in androgens in both females and males at puberty leads to abundant quantities of sebum which becomes infected -> leads to acnes

Front 254

hair

Back 254

formed by the epidermis and dermis together, hair follicle is comprised of a hair shaft and a hair bulb, NO hair follicles are formed after birth, hair growth is cyclic, filamentous, keratinized structures that project from the epidermal surface of the skin, function in tactile stimulation

Front 255

vellus hairs

Back 255

soft, fine, short and pale, found covering the eyelids

Front 256

terminal hairs

Back 256

hard, large, coarse, long and dark, found covering the scalp and eyebrows

Front 257

lanugo

Back 257

very fine hair, found on the fetus

Front 258

arrector pili muscle

Back 258

smooth muscle, it elevates the hair and causes goosebumps (depressions of the skin where the muscle attaches to the dermis), extend from midshaft of the hair follicle to the papillary layer of the dermis

Front 259

hair follicles

Back 259

develop form the epidermis and invade the dermis and hypodermis

Front 260

glassy membrane

Back 260

separates the dermis from the epithelium of the hair follicle

Front 261

hair bulb

Back 261

consists of the hair root and the dermal papilla (contains a rich supply of capillaries that provide nutrition and oxygen for the cells of the hair follicle)

Front 262

layers of hair (from superficial to deep)

Back 262

glassy membrane -> external root sheath -> internal root sheath (Henle’s layer, Huxleys layer and cuticle) (ends where sebaceous gland enters hair) -> hair (cuticle, cortex, medulla)

Front 263

matrix of the hair root

Back 263

proliferation occurs here and accounts for the growth of hair

Front 264

nails

Back 264

represent keratinized epithelial cells arranged in plates of hard keratin

Front 265

respiratory epithelium

Back 265

a PSCC with goblet cells

Front 266

respiration

Back 266

1. movement of air in and out of the lungs (breathing or ventilation)
2. exhcnage of O2 in the inspired air for CO2 in the blood (external respiration)
3. conveyance of O2 and CO2 to and from the cells (transport of gases)
4. exchange of CO2 for O2 in the vicinity of the cells (internal respiration)

Front 267

components of the respiratory system

Back 267

1. conducting portion-situated both outside and within the lungs, conveys air from the external milieu to the lungs
2. respiratory portion-located strictly within the lungs, functions in the actual exchange of oxygen for carbon dioxide

Front 268

conducting protion of the respiratory system

Back 268

provides conduit to transfer air, conditions the air (cleans, moistens and warms), combination of cartilage, elastic, collagen fibers, smooth muscle, elastic fibers concentration inversely proportional to diameter, elastic fibers found in lamina propria run longitudinally, smooth muscle mostly circular

Front 269

branching in the conducting portion of the respiratory system

Back 269

the total cross-sectional diameter of the various branches INC at each level of branching, this causes a decrease in the velocity of air as it proceeds toward the respiratory portion

Front 270

Kiessel-bach’s area

Back 270

nasal bleeding occurs here, the anteriorinferior region of the nasal septum

Front 271

cell types of the generic respiratory epithium

Back 271

1. ciliated columnar cells (30%)
2. columnar cell mainly serous secretion, serous cells (3%)
3. mucous goblet cells
4. brush or small mucous granule cells
5. diffuse endocrine or small granule cells
6. basal or immature cells
all contact the basement membrane, but they do not all reach the lumen

Front 272

ciliated columnar cells

Back 272

most predominate, continues until respiratory portion, cilia beat towards the mouth/nasopharynx for elimination

Front 273

columnar cell mainly serous secretion (serous cells)

Back 273

3%, columnar cells, they have apical microvilli and apical granules containing serous fluid

Front 274

mucous goblet cells

Back 274

30%, has theca (expanded secretory portion) and stem, synthesis of mucinogen, hydrated mucinogen turns to mucous, trap and remove bacteria/particles, continues until terminal bronchiole

Front 275

brush or small mucous granule cells

Back 275

no cilia, many microvilli, two kinds, (1) goblet cells that have released mucinogen, (2) one kind has nerve endings on basal surface, sensory receptor for gas volume and O2/CO2 concentration and intraepithelial receptor for trigeminal/sneeze reflex

Front 276

diffuse endocrine or small granule cells

Back 276

thought to control mucous and seromucous secretion, controls vessel diameter, also thought to play a regulatory role in O2 and CO2 levels, has granules that secrete agents that act as paracrine hormones, can exert local effects to alleviate localized hypoxic conditions

Front 277

basal cells or immature cells

Back 277

30%, rest on basement membrane and don’t reach the lumen -> pseudostratified, appear to be stem cell of goblet, ciliated columnar and brush cells

Front 278

metaplasia

Back 278

abnormal transformation of adult cells in a tissue to a form which is not normal for that tissue, this can be in response to a disease process, a physical, or chemical event, smokers respiratory epithelium shows an increase in goblet cells due to pollutants and a decrease in cilia due to carbon monoxide, reversible

Front 279

nasal cavity

Back 279

air is filtered, warmed and humidified by the nasal mucosa, contains olfactory mucosa, vestibule = anterior portion of the nasal cavity, vibrissae, nasal fossa with inferior, middle and superior conchae

Front 280

nasal cavity and how its importance clinically

Back 280

1. plasma cells located in the lamina propria release IgA and IgE, IgE binds to IgE receptors on mast cells and basophils, subsequent binding of allergen or antigen to this bound IgE/mast cell complex causes the release of inflammation mediators of the mast cell and basophile, these in turn act on the nasal mucosa resulting in symptoms associated with hay fever and colds
2. site of drug delivery since there is convenient access to a superficial venous plexus beneath the nasal cavity mucosa
3. drainage from maxillary sinus infections can be seen below the middle concha

Front 281

olfactory epithelium

Back 281

located on the roof of the nasal cavity and on the superior nasal conchae, thicker and lacks goblet cells

Front 282

cell types in the olfactory epithelium

Back 282

1. olfactory cell
2. sustentacular cells
3. basal cells

Front 283

olfactory cell

Back 283

bipolar neurons whose apical surfaces are modified to form the olfactory vesicle and olfactory cilia, dendrite terminates as bulbous olfactory vesicle 6-20 nonmotile cilia, synthesizes a odor receptor on its ciliated surface, odors dissolve in the serous fluid and attach onto an odorant binding protein produced by Bowman’s glands, once binding threshold reached olfactory receptors triggers impulse to olfactory bulb

Front 284

sustentacular cells

Back 284

apical surface has microvilli, has secretory granules, form junctional complexes with the olfactory cells, believe to provide physical support, nourishment and electrical insulation for the olfactory cells

Front 285

basal cells

Back 285

stem cell for all olfactory epithelium

Front 286

Bowman’s glands

Back 286

located in the lamina propria, synthesis of an odorant binding protein, seromucous secretion important in dissolving odors and cleans the surface, enhances a persons ability to detect odors, has a continuous flow of serous fluid that provides constant refreshments of the olfactory cilia

Front 287

swell bodies

Back 287

venous plexus in lamina propria that enlarge alternately on two sides of nasal cavity giving mucosa one occluded side, time to recover from desiccation and help to direct air to the olfactory epithelium, protects the nasal mucosa from dehydration

Front 288

paranasal sinuses

Back 288

air spaces within bone lined with respiratory epithelium, types include: frontal sinus, maxillary sinus, anterior ethmoid sinus and sphenoid sinus, communicate with the nasal cavity, has cilia that sweeps mucus layer toward the nasal cavity

Front 289

nasopharynx

Back 289

lined by respiratory epithelium, posterior aspect of the nasopharynx houses the pharyngeal tonsil (an unencapsulated collection of lymphoid tissue

Front 290

larynx

Back 290

larger hyaline plates and smaller elastic cartilage plates, connects trachea with pharynx, responsible for phonation (producing sounds) via the vocal cords, prevents entry of food and fluids into the respiratory system

Front 291

epiglottis

Back 291

tracheal and lingual side, two types of epithelium, elastic cartilage, during swallowing the backward motion of tongue forces epiglottis over the laryngeal opening closing the larynx and directing food into the esophagus, covered by stratified squamous nonkeratinzed epithelium and PSCC

Front 292

false vocal cords

Back 292

upper pair of folds, covered with respiratory epithelium, contain glands and no muscle

Front 293

true vocal cords

Back 293

covered with stratified squamous epithelium due to air movement, no glands, vocalis muscle (skeletal, alters the tension in the vocal folds) and vocal ligament (elastic fibers, reinforce the vocal folds), the longer and more relaxed the vocal folds, the deeper the pitch

Front 294

laryngitis

Back 294

inflammation of the laryngeal tissues, including the vocal folds, prevents the vocal folds from vibrating freely, sound hoarse or can only whisper

Front 295

tracheae

Back 295

16-20 rings bifurcates to form the primary bronchi, right more vertical wall of the trachea is reinforced by 10-12 hyaline cartilage rings (C-rings), open end of these rings face posteriorly

Front 296

levels of the tracheae

Back 296

1. epithelium-6 cell types of respiratory epithelium
2. lamina propria-seromucous glands that can extend into the submucosa, collagen and elastic fibers with well defined elastic lamina, contains lymphoid organs and mucous and seromucous glands, 1&2 make the mucosa layer of the trachea
3. submucosa-dense irregular CT housing numerous mucous and seromucous glands, release secretions on the epithelial surface through ducts that pierce through the mucosa, lymphoid elements are also present, has rich blood supply
4. adventitia-C shaped hyaline cartilage rings closed off by trachealis muscle, perichondrium fuses with submucosa and adventitia, anchors the trachea to the adjacent structures (esophagus and neck)

Front 297

bronchial tree (dichotomous)

Back 297

primary (extrapulmonary) bronchi, resembles tracheae, right-is straighter, trifurcates, left-bifurcates, are more rigid than intrapulmonary bronchi, cartilaginous rings become irregular, smooth muscle spirals between submucosa and cartilage, as one moves down the trachea notice a DEC in cartilage, numbers of glands and goblet cells and size of epithelial cells and an INC in smooth muscle and elastic tissue

Front 298

secondary and tertiary (intrapulmonary) bronchi

Back 298

secondary (lobar bronchi) goes to lobes, tertiary (segmental) goes to bronchopulmonary segments, repiratory epithelium, lamina propria and submucosa, rich elastic fibers, spiral smooth muscle, seromucous glands between cartilage plates and smooth muscle, C-rings disappear for irregularly shaped and placed hyaline cartilage

Front 299

bronchioles

Back 299

lack seromucous glands, no cartilage, by definition 1 mm or less, have clara cells in their epithelial lining, considered the 10th-15th generation of branching

Front 300

epithelium of bronchioles

Back 300

ciliated columnar with goblet cells to a ciliated columnar/cuboidal with clara cells and no goblet cells

Front 301

clara cells

Back 301

columnar cells with dome-shaped apices, short microvilli, no cilia, secrete glycoproteins that protects the mucosa, degrade airborne toxins by sER p450 cytochromes, divide to regenerate the bronchiole epithelium, goblet cells decrease as clara cells increase

Front 302

lamina propria of bronchioles

Back 302

predominately smooth muscle and elastic fibers, no cartilage or seromucous glands, have elastic fibers that help maintain the patency of the bronchioles

Front 303

innervation of bronchioles

Back 303

parasympathetic-bronchial constriction
sympathetic-bronchial dilation

Front 304

asthma

Back 304

widespread constriction of smooth muscle in the bronchioles during expiration causing decrease in diameter, different causes, often associated with allergic reactions, wheezing, difficulty expelling air from lungs (expiration)

Front 305

terminal bronchiole

Back 305

form the smallest and most distal region of the conducting portion of the respiratory system, comes from bronchiole branching, less than 0.5 mm, epithelium composed of clara cells and cuboidal cells with some cilia, lamina propria consists of a few layers of smooth muscle and fibroelastic CT

Front 306

respiratory portion of the respiratory system

Back 306

respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli

Front 307

respiratory bronchiole

Back 307

1. epithelium-simple ciliated cuboidal with clara cells
2. lamina propria-very thing smooth muscle and elastic fibers at alveolar openings alveoli
first region of the respiratory system where gas exchange occurs, wall is interrupted by alveoli

Front 308

alveolar ducts

Back 308

lined by a squamous epithelium (primarily Type I pneumocytes), smooth muscle and lots of elastic fibers in lamina propria, do not have walls of their own, lined by alveoli

Front 309

alveolar sacs

Back 309

branch of the alveolar duct, open into a common space called the atrium, an outpouching of two or more small clustgers of alveoli

Front 310

alveoli

Back 310

pouch-like evaginations, 85% of alveoli develop after birth, until the age of 10, interalveolar wall or septum (lined by both type I and type II pneumocytes), form the primary structural and functional unit of the respiratory portion, thin walls permit exchange of CO2 and O2, total about 300 million, opening is devoid of smooth muscle, instead their orifices are circumscribed by elastic and reticular fibers

Front 311

Type I pneumocytes

Back 311

simple squamous epithelium, very attenuated, exchange of gases, 95% of the alveolar surface, can not regenerate, can form occluding junctions with each other preventing the seepage of tissue fluid into the alveolar lumen, covered by basal lamina

Front 312

Type II pneumocytes

Back 312

cuboidal, 5% of the alveolar surface but more numerous, occluding junctions between type I and type II, can regenerate entire surface and even Type I pneumocytes, surfactant production (reduces surface tension), stored in lameallar bodies (TEM), present at 26-28 weeks in amniotic fluid, also have basal lamina

Front 313

hyaline membrane disease

Back 313

premature infants lack sufficient surfactant -> alveoli collapse, give mom glucocorticoids to induce synthesis of surfactant by baby

Front 314

interalveolar septum

Back 314

slender CT elements between alveoli, reinfore the alveolar duct, contains type I and II pneumocytes, elastic and reticular fibers (help keep structure and help in nonforced exhalation), continuous capillaries, two regions: (1) thin portion and (2) thick portion

Front 315

thin portion (TnP)

Back 315

exchange of gases, blood gas barrier (has 4 parts)
1. surfactant layer
2. cytoplasm of type I pneumocyte
3. fused basal lamina between type I and capillary endothelium
4. cytoplasm of the capillary endothelium

Front 316

thick portion

Back 316

continuous capillaries, elastic, collagen and reticular fibers, fibroblasts, macrophages, mast cells, there are no lymphatics from the alveolar air sacs distally, interalveolar septum is responsible for removing fluid from essentially a closed space through a wicking action, fluid diffuses proximally in the interstitium until it enters small lymphatics at about the level of the respiratory bronchioles, lymphatics then follow the bronchial tree

Front 317

dust cells

Back 317

macrophages, two types, associated with alveolar wall (fixed population) and those that roam free (free population), macrohpages produce elastase, digest foreign material (dust and bacteria) and excess surfactant

Front 318

heart failure cells

Back 318

are alveolar macrophages that have digested erythrocytes and stain positive for Fe (hemosiderin) in the RBCs

Front 319

pores of Kohn

Back 319

alveolar pores, equilibrate the pressure from alveoli to alveoli, allow passage of roaming macrophages, occur in areas where two alveoli touch and communicate

Front 320

pulmonary vasculature

Back 320

lung has a duel blood supply and venous drainage, pulmonary and bronchial

Front 321

pulmonary artery

Back 321

capillary component is site of gaseous exhcnage, pulmonary systolic pressure of 25 mmHg

Front 322

bronchial arteries

Back 322

follow the course of the bronchial tree, at systemic systolic pressure 110-135 mmHg, branches off of the thoracic aorta, follow bronchial tree to level of respiratory bronchioles, anastomose with branches of pulmonary artery, supply oxygen to the lungs

Front 323

surgery and lungs

Back 323

bronchopulmonary segments allow for surgical resection (segmental bronchus, pulmonary artery, and intersegmental pulmonary vein)

Front 324

emphysema

Back 324

destruction of interalveolar wall, DEC elasticity (lungs are unable to recoil), enough air, you just can’t move it, associated with exposure to cigarette smoke and other substances that inhibit alpha1-antitrypsin, alpha1-antitrypsin is a protein that protects the lung from action of elastase, can be hereditary, defective alpha1-antitrypsin enzyme

Front 325

poliomyelitis

Back 325

causes muscles of respiration to be weakened, causes accessory muscles to hypertrophy because they become responsible for the elevation of the thoracic cage

Front 326

myasthenia gravis and Guillain-Barre syndrome

Back 326

weakness of the respiratory and accessory respiratory muscle may lead to respiratory failure and consequent death even through the lungs function normally

Front 327

functions of the lymphoid system

Back 327

1. defense against foreign substances (antigens), microorganisms, tumor, transplanted and virus infected cells, does so by concentrating and eliminating antigens, production and maturation of lymphocytes and addition of antibodies, 2nd and 3rd line of defense (1st is skin)
2. providing a means for returning tissue fluid back into the blood stream through lymphatic vessels
3. absorption of chylomicrons from the small intestine

Front 328

encapsulated organs

Back 328

lymph nodes, tonsils, thymus, spleen

Front 329

diffuse lymphoid tissue

Back 329

MALT: GALT, BALT, lymphocytic infiltration where needed

Front 330

innate immune systems

Back 330

rapid, no antigenic specificity, no memory, preformed or rapidly formed components, self/non-self recognition, composed of:
1. blood-borne macromolecules known as complement
2. groups of cells known as macrophages and neutrophils, which phagocytose invaders
3. NK cells which kill tumor cells, virally infected cells, bacteria and parasites

Front 331

approximate percentage of lymphocytes in lymphoid organs

Back 331

thymus: T 100% B 0%
bone marrow: T 10% B 90%
spleen: T 45% B 55%
lymph nodes: T 60% B 40%
blood: T 80% B 20%

Front 332

components of the innate immune system

Back 332

complement, antimicrobial peptides, cytokines, macrophages, neutrophils, NK cells, and Toll-like receptors

Front 333

complement

Back 333

a series of blood borne proteins that attack microbes that found their way into the bloodstream, form membrane attack complex (MAC) that damages the microbe’s cell membrane, may tag microbes with C3b for phagocytosis by neutrophils and macrophages

Front 334

antimicrobial peptides

Back 334

defensins, synthesized and released by epithelial cells and not only defend against gram-negative bacteria but also are chemoattractants for immature dendritic cells and T cells

Front 335

cytokines

Back 335

signaling molecules to effect responses from target cells

Front 336

Interleukins (ILs)

Back 336

cytokines released by lymphocytes

Front 337

chemokines

Back 337

cytokines that possess chemoattractant capabilities

Front 338

colony-stimulating factors (CSFs)

Back 338

stimulate differentiation and mitotic activity of hemopoietic cells

Front 339

interferons

Back 339

cytokines that display antiviral properties

Front 340

macrophages

Back 340

have receptors for the constant portions (Fc) of antibodies, complement and carbohydrates on surfaces of foreign substances, are APCs to T and B cells, induce release of neutrophils

Front 341

neutrophils

Back 341

react to inflammation, phagocytose and destroy bacteria

Front 342

NK cells

Back 342

similar to cytotoxic T cells but do not have to enter the thymus to become mature killer cells, use nonspecific markers to recognize their target cells, produce perforins and granzymes which cause apoptosis in the target cell, use 2 methods
1. antibody-dependent cellular cytotoxicity-possess Fc receptors for IgG antibody and kill the target
2. has killer-activating receptors that bind to markers on the surface of nucleated cells, also have killer-inhibiting receptors that recognize MHC1 molecules that prevent killing of healthy cells

Front 343

how do tumor cells avoid destruction

Back 343

they suppress MHC1 molecules that are normally detected by cytotoic T cells and evade destruction, MHC1 also noticed by killer-inhibiting receptor of NK cells

Front 344

toll-like recetpros (TLRs)

Back 344

conserved integral proteins present in the membranes on cells of the innate immune system, integration of other TLRs leads to a cascade that activates the release of cytokines appropriate to the pathogen being detected and also activation of B and T cells

Front 345

hypoactivity of TLRs

Back 345

can result in greater susceptibility to pathogens

Front 346

hyperactivity of TLRs

Back 346

may be responsible for autoimmune diseases such as lupus and rheumatoid arthritis

Front 347

adaptive immune system

Back 347

slow, antigenic specificity, immunological memory, diversity and recognizes “altered self” and self/nonself, responsible for eliminating threats from specific invaders, depends on B and T lymphocytes to mount an immune response

Front 348

cytokines and adaptive immune system

Back 348

B and T cells and APCs use cytokines to communicate with each other and the innate immune system when encountering antigens

Front 349

humoral immune response

Back 349

the immune response that depends on the formation of antibodies (immunoglobulins), B cells are responsible for this

Front 350

cell-mediated immune response

Back 350

the immune response responsible for the cytotoxic response, uses T cells

Front 351

where are the functional components of both immune systems formed

Back 351

bone marrow

Front 352

where do B cells and NK cells become immunocompetent

Back 352

bone marrow (called a primary (central) lymphoid organ)

Front 353

where do T cells become immunocompetent

Back 353

thymus (called a primary (central) lymphoid organ)

Front 354

secondary (peripheral) lymphoid organs

Back 354

after immunocompetence, the B and T cells migrate here, include diffuse lymphoid tissue, lymph nodes and spleen, this is where they come into contact with antigens

Front 355

immunogens

Back 355

molecules that always elicit an immune response

Front 356

antigens

Back 356

bind to antibodies but do not necessarily elicit an immune response

Front 357

epitope

Back 357

antigenic determinant, where an antigen binds to an antibody

Front 358

clonal selection and expansion

Back 358

during embryonic development, an extremely large number of small clusters (clones) of lymphocytes are formed, each clone recognizes one specific foreign antigen

Front 359

primary immune response

Back 359

when the antibody first comes into contact with the antigen, slow and not very robust

Front 360

secondary immune response

Back 360

subsequent exposure to the same antigen, begins rapidly and is much more intense than the primary response, this is due to immunological memory (after primary response, virgin cells proliferate to form activated cells and memory cells)

Front 361

activated (effector) cells

Back 361

carry out an immune response, B cell derived are called plasma cells and produce antibodies, T cell derived secrete cytokines or destroy the foreign cell

Front 362

memory cells

Back 362

express B or T cell receptors which interact with a specific antigen, have a greater affinity for the antigen which allows for the second response to be faster and stronger

Front 363

immunological tolerance

Back 363

allows the immune system to recognize self and not destroy itself, works by killing cells that would attack self

Front 364

autoimmune disease

Back 364

involve a malfunction of the immune system that results in the loss of immunological tolerance, ex: Grave’s disease (receptors for TSH are perceived to be antigens, release excess thyroid hormones)

Front 365

immunoglobulins

Back 365

are antibodies manufactured by plasma cells, has one pair of heavy chains and one pair of light chains attached to each other by disulfide bonds, are glycoproteins that inactivate antigens and elicit an extracellular response, released into the lymph or blood vascular system

Front 366

protein C3 deficiency

Back 366

predisposes a person to recurring bacterial infections

Front 367

epitope binding site on antibody

Back 367

found on the distal aminto terminal ends, four ends, Fc region, so each antibody molecule can bind to two identical epitopes

Front 368

antigen binding site on antibody

Back 368

found on Fab fragment which is the two identical stem fragments of the heavy chains, changes in the sequence of this fragment determine the specificity for certain antigens

Front 369

how many isotopes of immunoglobulins are there

Back 369

5 (IgM (pentameric), IgA (dimeric), IgG (monomeric), IgD (B cells), and IgE (basophils and mast cells))

Front 370

B lymphocytes

Back 370

responsible for the humorally mediated immune response (antibody), mature cells are CD 40+, upon antigen stimulation B lymphocytes proliferate and differentiate into plasma cells or B memory cells

Front 371

plasma cells

Back 371

have a clock face, synthesize/secrete Ab to antigens, responsible for the primary response, produced when the B cell is activated (when the antigen binds to the immunoglobulin),

Front 372

B memory cells

Back 372

same as T memory, responsible for the secondary response, long term immunity (corona or mantle layer lymphoid nodule), found in all lymphoid tissues (but very few in thymus medulla)

Front 373

function of B cells

Back 373

humoral immunity, antibody production, control of pyogenic bacteria, prevention of blood-borne infections, neutralizations of toxins, 12%, mainly fixed, produced in the germinal center of lymph nodes and spleen

Front 374

thymic independent antigens

Back 374

antigens can elicit a humoral immune response without a T-cell intermediary, do not induce B memory cell formation

Front 375

T lymphocytes

Back 375

cell mediated immunity against antigens (microorganisms, infected cells, tumor and transplant cells), produce cytokines, TCR present on the surface recognize only protein antigens, can differentiate self from non-self, found in thymus dependent regions of the body

Front 376

thymus dependent regions of the body

Back 376

paracortical regions of the lymph nodes, periarterial sheaths of the spleen

Front 377

subtypes of the T cells

Back 377

1. T helper cells (TH1 and TH2, are cluster differentiation 4+ cells)
2. T cytotoxic cells (TC; cytotoxic T lymphocytes (CTL); are CD8+ cells)
3. T suppressor cells (are CD 8+ cells)
4. T memory cell

Front 378

function of T cells

Back 378

cell-mediated immunity, protection against intracellular organisms, protozoa and fungi, graft rejection, control of neoplasms, 70-80% mainly circulating long-lived memory cells, produced in paracortical region of lymph nodes, spleen

Front 379

differences between T cells and B cells

Back 379

1. T cells have TCRs rather than sIgs on their cell surface
2. T cells recognize only epitopes presented to them by other cells (APCs)
3. T cells response only to protein antigens
4. T cells perform their functions only at short distances

Front 380

clusters of differentiation proteins (CD markers)

Back 380

expressed by T cells, bind to specific ligands on target cells, TCR associates with CD3, 4, and 8 to form a TCR complex

Front 381

major histocompatiblity complex (MHC) complex

Back 381

TCRs only recognize proteins and epitopes bound to MHC complexes, T cell must bind to both MHC and epitope to become activated, present epitopes of pathogens to T cells, two classes MHCI (all cells) and MHCII (only APCs synthesize and display these), how T cells distinguish self

Front 382

naïve t cells

Back 382

possess CD45RA, leave the thymus programmed as immunologically competent cells, but must be activated before it can act like that, when activated forms memory T cells and effector T cells

Front 383

Memory T cells

Back 383

two types: (1) central memory T cells (TCMs, CR7+) and (2) effector memory T cells (TEMs, CR7-), are responsible for the immunological memory of the adaptive immune system, have the capability of combating a particular antigen, memory cells can become activated themselves and express effector capabilities

Front 384

TCMs

Back 384

remain in the lymph nodes, incapable of immediate effector function, they interact with and stimulate APCs, this stimulates TCM and differentiates them into TEMs

Front 385

TEMs

Back 385

express receptors that permit these cells to migrate to regions of inflammation, where they have immediate effector function by differentiating into T cells

Front 386

effector T cells

Back 386

three types (helper, cytotoxic, and regulatory), these response to an immunological challenge

Front 387

T helper cells

Back 387

display CD4 on their membrane and are responsible for the recognition of foreign antigens as well as for mounting an immunological response against them, can also stimulate the humorally mediated immune system, Th0 cells can differentiate into the other two types and is responsible for releasing cytokines

Front 388

cytotoxic t lymphocytes (CTLs, T killer cells)

Back 388

display CD8 and are responsible for killing foreign cells, tumor cells and virally altered cells, these recognize the epitopes on foreign cells and kill them (in 1 of 2 ways)

Front 389

regulatory t cells

Back 389

possess CD4 and function in suppressing the immune response, two types (natural (from the thymus) and inducible (from naïve T cells))

Front 390

natural T killer cells

Back 390

recognize lipid antigens, recognize CD1

Front 391

antigen presenting cells (APCs)

Back 391

express both MHCI and MCHII on plasmalemma, phagocytose, catabolize, process, and present antigen, produce cytokines, many belong to the mononuclear phagocytic system, include macrophages, dendritic cells and B cells

Front 392

human immunodeficiency virus (HIV)

Back 392

binds to CD4 molecules of T helper cells and injects ins core into the cell, this incapacitates the cell and affects other T helper cells, causes individuals to become incapable of mounting an immune response against bacterial and viral infections

Front 393

lymphoid organs

Back 393

two categories
1. primary (central) lymphoid organs-responsible for the development and maturation of lymphocytes into mature, immunocompetent cells (fetal liver, bone marrow, thymus
2. secondary (peripheral) lymphoid organs-responsible for the proper environment in which immunocompetent cells can react with each other (lymph nodes, spleen and lymphoid tissue)

Front 394

thymus origin and development

Back 394

located in the superior mediastinum, derived from both endoderm (epithelial reticular cells) and mesoderm (lymphocytes), growth occurs until mid teens then undergoes involution (atrophy) with fat accumulation

Front 395

thymus function

Back 395

maturation and differentiation of T cells

Front 396

thymus structure

Back 396

no afferent lymphatics, 99% T cells therefore there are no germinal centers, bilobed and encapsulated (dense irregular CT) which turns inward (giving off septa) dividing the lobe into lobules, lobuels arranged into cortex and medulla

Front 397

thymic cortex

Back 397

immunological competency of T cells, elimination of self-intolerant T cells and MHC recognition occur here, stains darker than the medulla, also houses macrophages and epithelial reticular cells

Front 398

epithelial reticular cells

Back 398

responsible for forming the separation between the cortex and blood vessels, prevents antigens from contacting thymoctyes, three types in cortex:
1. Type I-separate the cortex from the connective tissue capsule and surround vascular elements in the cortex
2. Type II-located in the midcortex, subdivides the cortex into small, lymphocyte-filled compartments
3. Type III-located in the deep cortex and at the corticomedullary junction, isolate the cortex from the medulla
three types in the medulla:
4. Type IV-found in close associate with type III, assist in the formation of the corticomedullary junction
5. Type V-forms the cytoreticulum of the medulla
6. Type VI-form Hassall’s corpuscles, may be the site of T cell death in the medulla

Front 399

thymic medulla

Back 399

characterized by the presence of Hassall’s corpuscles, all thymocytes of the medulla are immunocompetent T cells, stains lighter than the cortex, allow for mature T cells to leave the thymus through veins that drain the thymus

Front 400

vascular supply of the thymus

Back 400

the cortical vascular supply forms a very powerful blood-thymus barrier to prevent developing T cells from contacting blood-borne macromolecules, continuous capillaries invested by type I epithelial reticular cells to form a blood-thymus barrier

Front 401

DiGeorge’s syndrome

Back 401

congenital failure of the thymus to develop, patient’s cannot produce T cells, have a non-functional cellularly mediated immune response, die at an early age from infection

Front 402

lymph nodes

Back 402

they are not glands, situated in course of lymph vessels that allows for lymph to pass through before entering blood stream

Front 403

lymph node functions

Back 403

immune filter, remove bacteria and other foreign substances, maintain and produce T and B cells, house T memory cells, APCs and macrophages in paracortical region

Front 404

lymph node structural features

Back 404

encapsulated-CT extending inward as trabeculae, afferent lymphatics enter the capsule, hilus for passage of arterioles, venules and efferent lymphatics, separated into cortical and medullary regions, valves on efferent lymph vessels

Front 405

lymph nodes and infection

Back 405

in the presence of antigens or bacteria, lymphocytes of the lymph node rapidly proliferate and the node may INC to several times its normal size becoming hard a palpable to the touch

Front 406

lymph node cortex

Back 406

subdivided into compartments that house B-cell rich primary and secondary lymphoid nodules

Front 407

subscapular sinus of lymph node

Back 407

where lymph is emptied into, located just deep to the capsule, is continuous with the cortical sinuses (paratrabecular sinuses) that parallel the trabeculae and deliver the lymph into the medullary sinuses eventually to enter the efferent lymphatic vessels

Front 408

lymphoid nodules

Back 408

two types of nodules (primary and secondary), secondary lymphoid nodules have a germinal center
1. primary-incomplete compartments within the cortex, spherical aggregates of B cells (both virgin and memory)
2. secondary-have germinal centers that stain pale, form only in response to an antigenic challenge, they are the sites of B memory cell and plasma cell generation

Front 409

corona (mantle zone)

Back 409

peripheral layer around the germinal center, an accumulation of small lymphocytes migrating away from its site of origin (germinal center)

Front 410

three zones of a germinal center

Back 410

1. dark zone-site of the intense proliferation of closely packed B cells (centroblasts), these migrate into the basal light zone
2. basal light zone-where B cells express sIgs, switch immunogloculin class and are known as centrocytes
3. apical light zone-house centrocytes that become either B memory cells or plasma cells

Front 411

paracortex of the lymph node

Back 411

region of the lymph node between the cortex and the medulla, houses mostly T cells and is the thymus-dependent zone of the lymph node, APCs migrate here to present their epitope MHC II complex to T helper cells, have high endothelial venules

Front 412

medulla of the lymph node

Back 412

composed of large, tortuous lymph sinuses surrounded by lymphoid cells that are organized in cluster known as medullary cords, these cells are enmeshed in a network of reticular fibers and reticular cells, lymphocytes migrate from the cortex to enter the medullary sinuses from which they can enter the efferent lymphatic vessels to leave the lymph node, trabeculae can also be present conveying blood vessels all the way into this region

Front 413

spleen

Back 413

found in the left hypochondrium, the largest lymphoid organ in the body

Front 414

spleen functions

Back 414

hemopoiesis fetus, immunological filter of blood, acts as a blood reservoir, phagocytosis of damaged and aged RBCs, proliferation of B and T cells, production of Abs by plasma cells

Front 415

spleen structure

Back 415

no afferent lymphatics, surrounded by a fibrous capsule containing some smooth muscle, has a 3-D network of reticular fibers and associated reticular fibers, trabeular from capsule breakup the parenchyma (or splenic pulp) into incomplete compartments, within the parenchyma there are red and white pulps

Front 416

periarterial lymphatic sheath (PALS)

Back 416

a sheath of lymphocytes that infiltrate the tunica adventitia of trabecular arteries, this forms the central artery, frequently PALS also house lymphoid nodules (which are composed of B cells, displace the central artery to the periphery), these lymphoid nodules may display a germinal center

Front 417

white pulp

Back 417

composed of the PALS housing T cells and lymphoid nodules housing B cells, with medial germinal center

Front 418

marginal zone

Back 418

houses B cells that are specialized to recognize thymic-independent antigens, surround the white pulp and separates it from the red pulp, composed of plasma cells, T and B cells, macrophages and APCs, it is here that blood-borne cells, antigens and particulate matter have their first free access to the parenchyma of the spleen

Front 419

red pulp

Back 419

composed of splenic sinuses and splenic cords (of Billroth), resembles a sponge, the spaces within the sponge represent the sinues and the sponge material among the spaces denotes the splenic cords

Front 420

splenic sinuses

Back 420

surrounded by reticular fibers that wrap around the sinuses, have a discontinuous basal lamina

Front 421

splenic cords

Back 421

composed of a loose network of reticular fibers whose interstices are permeated by extravasated blood, reticular fibers enveloped by stellate reticular cells which prevent coagulation of blood with collagen type III there

Front 422

lymphoid nodules

Back 422

mucosal associated lymphatic tissue (MALT) (includes GALT and BALT), found in tonsils, lymph nodes and spleen, not found in the thymus, primarily composed of B cells, lymphoblasts, plasma cells, memory cells, primary nodule = one that has not seen antigen, secondary nodule = one with a germinal center, do not have a connective tissue capsule

Front 423

tonsils

Back 423

aggregate of lymphoid nodules grouped around surface depressions called crypts, no afferent lymphatic vessels, only efferent, form a ring of protection at the openings of the digestive and respiratory tracts, possess an incomplete capsule of CT which acts as a protective barrier against leakage of antigen into pharyngeal CT spaces, possess antigen presenting cells

Front 424

Mucosa-associated lymphoid tissue (MALT)

Back 424

nonencapsulated localized lymphocyte infiltration

Front 425

Gut-associated lymphoid tissue (GALT)

Back 425

located in the ileum as Peyer’s patches, composed of lymphoid follicles along the length of the GI tract and may form aggregates, Peyer’s patches composed of B cells surrounded by a looser region of T cells and numerous APCs, lymphocytes destined to enter GALT have homing receptors that are specific for the HEVs of GALT

Front 426

Bronchus-associated lymphoid tissue (BALT)

Back 426

similar to Peyer’s patches except that it is located in the walls of bronchi, especially in regions where bronchi and bronchioles bifurcate, most are B cells although APCs and T cells may be present, lymphocytes destined to enter BALT have homing receptors that are specific for the HEVs of this lymphoid tissue

Front 427

tonsils

Back 427

incompletely encapsulated aggregates of lymphoid nodules that guard the entrance to the oral pharynx, react to airborne antigens by forming lymphocytes and mounting an immune response

Front 428

palatine tonsils

Back 428

located at the boundary of the oral cavity and the oral pharynx, its deep aspect is isolated form the surrounding CT by a dense capsule, superficial aspect is stratified squamous nonkeratinized epithelium, crypts are present that invaginate the tonsilar parenchyma (freq. contain food debris, dead leukocytes, bacteria and other antigenic substances

Front 429

pharyngeal tonsil

Back 429

single, is in the roof of the nasal pharynx, has a thinner incomplete capsule, has shallow pleats instead of crypts, superficial surface is PSCC that is interspersed with stratified squamous epithelium, composed of lymphoid nodules

Front 430

linguinal tonsil

Back 430

located on the dorsal surface of the posterior 1/3 of the tongue, covered by stratified squamous nonkeratinized epithelium, has a flimsy capsule that separates it from the underlying connective tissue, has numerous crypts, parenchyma is composed of lymphoid nodules, which freq. have germinal centers