Histo2

Front 1

central nervous system

Back 1

brain and spinal cord

Front 2

peripheral nervous system

Back 2

-cranial
-spinal
-peripheral nerves
-ganglia
-specialized nerve endings

Front 3

autonomic nervous system

Back 3

-sympathetic
-parasympathetic
The sympathetic division typically functions in actions requiring quick responses. The parasympathetic division functions with actions that do not require immediate reaction.
heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition - (the discharge of urine), and erection

Front 4

schwann cells

Back 4

provide myelination to axons in the peripheral nervous system (PNS). They also have phagocytotic activity and clear cellular debris that allows for regrowth of PNS neurons.

Front 5

satellite cells

Back 5

are small cells that line the exterior surface of PNS neurons and help regulate the external chemical environment

Front 6

ganglion

Back 6

sensory neurons in one spot

Front 7

sensory neurons

Back 7

convey impulses from receptors to the CNS.
Axons of these cells are called afferent fibers.

Front 8

motor neurons

Back 8

convey impulses from the CNS to effector cells. These are both somatic and visceral efferent fibers.

Front 9

interneurons

Back 9

elements of a communicating and integrating network interposed btwn the sensory and motor neurons.

More than 99% of the neurons of the nervous system are interneurons.

Front 10

neurons:
multipolar
bipolar
unipolar (pseudounipolar)

Back 10

bipolar neurons: spiral ganglion
pseudounipolar neurons:T-bifurcation

Front 11

neurons are ___ bodies?

Back 11

Nissle bodies

Front 12

Chemical synapses

Back 12

most common mode of communication btwn 2 nerve cells

Front 13

electrical synapses

Back 13

commonn in invertebrates but rare in mammals. they have been described in the brain stem, cerebral coretex, retina of mammals, and are like the gap junctions in smooth and cardiac muscle.
Current spreads directly from cell to cell due to ion flow.

Front 14

neurofilaments and microtubules

Back 14

microtubules play a role in transport.

Front 15

synaptic vesicles contain ? and accumulate where?

Back 15

synaptic vesicles containing neurotransmitters accumulate near the pre-synaptic membrane.

Front 16

pre-synaptic membrane is the cite where...

Back 16

On arrival of the action potential the vesicles dock with the membrane and release their contents into the synaptic cleft by exocytosis.

Front 17

synaptic cleft is where the...

Back 17

where the vesicles release their contents by exocytosis

Front 18

post synaptic membrane whose receptors are stimulated by?

Back 18

neurotransmitter diffuses across the synaptic cleft to stimulate the receptors in the post synpatic membrane.

Front 19

which neurotransmitters are excitatory?

Back 19

1.acetylcholine
2.norepinephrine
3.glutamic acid
4.serotonin

Front 20

which neurotransmitters are inhibitory?

Back 20

1.gamma-aminobutyric acid
2.dopamine
3.glycine
4.endorphins and enkephalins: inhibit pain

Front 21

80% of neurotransmitters dumped into the synaptic cleft will undergo?

Back 21

high affinity reuptake

Front 22

20% of neurotransmitters dumped into the synaptic cleft will undergo?

Back 22

degradation, e.g. acetylcholinesterase degrades acetylcholine

Front 23

axonal transport:

anterograde

Back 23

anterograde transport moves organelles, vesicles, macromolecules, and enzymes needed for neurotransmitter synthesis.

Front 24

retrograde

Back 24

moves protein building blocks for neurofilaments, subunits of microtubules, and enzymes.

Front 25

kinesis is?

Back 25

a microtubule-associated protein, in involved in aterograde transport

Front 26

central nervous system

Back 26

brain and spinal cord

Front 27

peripheral nervous system

Back 27

-cranial
-spinal
-peripheral nerves
-ganglia
-specialized nerve endings

Front 28

autonomic nervous system

Back 28

-sympathetic
-parasympathetic

Front 29

schwann cells

Back 29

form myelin sheath

Front 30

satellite cells

Back 30

form ganglia cells, dorsal root

Front 31

ganglion

Back 31

sensory neurons in one spot

Front 32

sensory neurons

Back 32

convey impulses from receptors to the CNS.
Axons of these cells are called afferent fibers.

Front 33

motor neurons

Back 33

convey impulses from the CNS to effector cells. These are both somatic and visceral efferent fibers.

Front 34

interneurons

Back 34

elements of a communicating and integrating network interposed btwn the sensory and motor neurons.

More than 99% of the neurons of the nervous system are interneurons.

Front 35

neurons:
multipolar
bipolar
unipolar (pseudounipolar)

Back 35

bipolar neurons: spiral ganglion
pseudounipolar neurons:T-bifurcation

Front 36

neurons are ___ bodies?

Back 36

Nissle bodies

Front 37

Chemical synapses

Back 37

most common mode of communication btwn 2 nerve cells

Front 38

dynein is involved with with axonal transport?

Back 38

microtubule associated protein is involved in retrograde transport.

Front 39

neuroglia: oligodendrocytes

Back 39

olgodendroglia/Oligodendrocytes are cells that coat axons in the central nervous system (CNS) with their cell membrane, called myelin, producing the so-called myelin sheath. The myelin sheath provides insulation to the axon that allows electrical signals to propagate more efficiently.
Glial cells provide support and protection for neurons, the other main type of cell in the central nervous system. They are thus known as the "glue" of the nervous system. The four main functions of glial cells are to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens and remove dead neurons.

Front 40

neuroglia:fibrous astrocytes

Back 40

are non-neuronal cells that provide support and nutrition, maintain homeostasis, form myelin, and participate in signal transmission in the nervous system. In the human brain, glia are estimated to outnumber neurons by about 10 to 1.
The most abundant type of glial cell, astrocytes (also called astroglia) have numerous projections that anchor neurons to their blood supply. They regulate the external chemical environment of neurons by removing excess ions, notably potassium, and recycling neurotransmitters released during synaptic transmission.

Front 41

chyroid plexus

Back 41

is the area on the ventricles of the brain where cerebrospinal fluid (CSF) is produced by modified ependymal cel

Front 42

meninges

Back 42

The meninges (singular meninx) is the system of membranes which envelop the central nervous system. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.

Front 43

blood is composed of? and is what kind of tissue?
-is derived from ?

Back 43

a specialized connective tissue composed of RBCs, platelets, suspended in a fluid matrix (blood plasma).
it is derived from mesenchyme

Front 44

total volume of blood in human is about ?
-has a pH of ?
-what is necessary to stop flow if the vascular tree is damaged? and how is it mediated?

Back 44

6 liters
-about 7.4
coagulation is mediated by platelets and blood borne factors that transform blood froma sol to a gel.

Front 45

what are the fxns of blood?
(4 fxns)

Back 45

-it is a vehicle for transport of material waste products to organs of elimination, hormones and other signaling molecules to cells, O2 from lungs to cells, and CO2 from cells to lungs.
-regulates body temp
-maintains acid-base and osmotic balance
-is a pathway for migration of white blood cells btwn the connective tisse comps. of body.

Front 46

what is plasma? (4 pts)

Back 46

a yellowish fluid with the solid elements, organic elements, and the electrolytes suspended or dissolved in it.
-H2O is 90%, proteins 9%, inorganic salts, ions, nitrogenous compnds and gases 1% of the vol.
-fluid component exits the vessels to become extracellular (tissue)fluid
-albumin doesn't exit

Front 47

albumin is responsible for?

Back 47

colloid osmotic pressure of blood that maintains normal blood and interstitial fluid volumes.

Front 48

erythrocytes are?
leucocytes are?

Back 48

RBCs
WBCs

Front 49

erythrocytes described...

Back 49

-biconcave disks
-organelles are expelled from the cell during maturation and development before entering the circulation.
-5mill. cells/cubic mm. of blood in males, 4.5 mill.cells/cubic mm. in females.

Front 50

erythrocytes...
-ave lifespan
-what determines blood type?
-what produces lysis?
-what is the Rh factor?

Back 50

-120 days
-aging RBCs develop a surface coating of oligosaccharide sugars and are destroyed by macrophages of the spleen, bone marrow, and liver.
-specific inherited carb chains in the plasmalemma determine the blood grp of the indiv. A, B, AB, or O.
-ppl who lack A, B or both have antibodies against the missing antigen which produces lysis
-Rh factor is a group of antigens, 3 of which (C,D,E) are common-85% of Americans-and are considered Rh + (Individuals either have, or do not have, the Rhesus factor (or Rh D antigen) on the surface of their red blood cells)

Front 51

what is lysis?

Back 51

the death of a cell by breaking of the cellular membrane, often by viral or osmotic mechanisms that compromise its integrity

Front 52

Leucocytes have two groups:
1.
2.

Back 52

granulocytes with conspicuous specific granules in the cytoplam
-agranulocytes which lack granules in cytoplasm
-both groups have nonspecific (azurophilic granules thought to be lysosomes) in their cytoplasm.

Front 53

neutrophils

Back 53

are the most abundant type of white blood cells and form an integral part of the immune system.
-these phagocytes during the acute phase of inflammation, particularly as a result of bacterial infection, leave the vasculature and migrate toward the site of inflammation in a process called chemotaxis. They are the predominant cells in pus, accounting for its whitish/yellowish appearance. Neutrophils react within an hour of tissue injury and are the hallmark of acute inflammation

Front 54

eosinophils

Back 54

only 5% of WBCs
-sausage shaped, bilobed nucleus connected by a thin strand
-has large eosinophilic specific granules
-nonspecific azurophilic granules
-found in large numbers in parasitic infections and in local allergic responses.

Front 55

basophils

Back 55

1% of WBCs
-S-shaped nuclues often masked by the large specific granules of the cytoplasm
-these are initiators of the inflammatory response and contribute to the anaphylactic rxn (Anaphylaxis is an acute systemic (multi-system) and severe Type I Hypersensitivity allergic reaction in humans and other mammals. )

Front 56

agranulocyte: monocyte

Back 56

largest cell
-large kidney shaped nucleus
-they stay in circulation only a few days and migrate thru the endothelium of venules to become macrophages
-2-6% of total WBCs

Front 57

agranulocyte: lymphocyte
T cells-
B cells-
Null cells-

Back 57

T cells are involved in cell-mediated immunity whereas B cells are primarily responsible for humoral immunity (relating to antibodies).
-Null cells-lymphocyte without T- or B-cell markers on its surface

Front 58

platelets
-described
-produced by?
-store what?
-key role?
-how many in blood?
-lifespan?

Back 58

small disk-shaped, non-nucleated cell fragments
-produced by megakaryocytes, giant cells of the red bone marrow, fragmentation of their cytoplasm.
-store serotonin in granules and platelet-derived growth factor in either granules.
-key role is to terminate hemorrhage (loss of blood)
-there are 250,000-400,000 platelets per cubic mm. of blood and their lifespan is less than 14 days.

Front 59

Hematopoiesis
-sites of, in adults?

Back 59

process by which mature blood cells develop from precursor cells. *development of blood cell compartments
-sites of hemopoiesis in adults, bone marrow of:
-skull
-ribs
-sternum
-vertebral column
-pelvis
-proximal ends of femora

Front 60

Hemopoiesis
-before birth hemopoiesis occurs in?
-active sites of hemopoiesis ___ with age...

Back 60

before birth this occurs in other places like the liver and spleen
-liver and spleen can be recalled to duty in times of need
-active sites of hemopoiesis decrease with age, but the potential remains

Front 61

bone marrow is...
-the stroma contains?...

Back 61

-a meshwork of vascular sinuses and branched network of reticular connective tissue
-heterogeneous pop of forming blood cells at their various stages of differentiation and maturation
-the stroma contains endothelial cells, macrophages, fibroblasts, and myeloid reticular cells. fat storing cells are plentiful.

Front 62

bone marrow fxns...

Back 62

in blood formation from the 5th month til death
-long bone diaphyses house only yell marrow after age 20
-vascular supply is from nutrient arteries

Front 63

prenatal hemopoiesis has four phases:

Back 63

1.mesoblastic (yolksac, 2 wks to 6th wk)
2.hepatic (6wks to birth)
3.splenic (2nd trimester to birth)
4. myeloid (end of 2nd trimester and increases in importance)

Front 64

erythropoiesis

Back 64

is the process by which red blood cells (erythrocytes) are produced. In human adults, this usually occurs within the bone marrow. In the early fetus, erythropoiesis takes place in the mesodermal cells of the yolk sac. By the third or fourth month, erythropoiesis moves to the spleen and liver. In humans with certain diseases and in some animals, erythropoeiesis also occurs outside the bone marrow, within the spleen or liver.

Front 65

•what are the components of The Cardiovascular System?

Back 65

The heart and blood vessels.

Front 66

The Lymph Vascular System:

Back 66

A system of vessels found throughout most of the body. It drains its contents into large veins of the cardiovascular system

Front 67

•Circuits consist of:

Back 67

* arteries
* capillaries
* veins
* arteriovenous shunts (anastomoses)

Front 68

ARTERIES CONSIST OF 3 TUNICS:

Back 68

-Tunica Intima: endothelium on a basal lamina and underlying connective tissue.
-Tunica Media: a muscular layer with some connective tissue fibers.
-Tunica Adventitia: an outermost coat of mostly loose connective tissue.

Front 69

ARTERIAL SYSTEM consists of 3 MAIN VESSELS *transition btwn these is gradual

Back 69

-elastic arteries
-muscular arteries
-arterioles

Front 70

elastic arteries

Back 70

the aorta, innominate artery, common carotid artery, subclavian & most pulmonary arterial vessels.

Front 71

muscular arteries

Back 71

the main distributing branches, e.g. the radial, femoral, and cerebral arteries.

Front 72

arterioles

Back 72

: terminal branches which supply the capillaries

Front 73

muscular distsributing arteries: tunica intima

Back 73

• Tunica Intima: Endothelium on the luminal border, resting upon the internal elastic lamina. The latter is a conspicuous wavy pink refractile line. The basal lamina of the epithelium lies in close apposition to this lamina.

Front 74

muscular distributing arteries: tunica media

Back 74

• Tunica Media: A thick circular layer of smooth muscle, consisting of smooth muscle cells and some elastic & collagen fibers as well.
-• The outer border of the media is marked by the external elastic lamina, which is less conspicuous and appears less continuous than the internal elastic lamina.

Front 75

muscular distributing arteries: tunica adventitia

Back 75

Thickness varies, and consists mostly of elastic fibers, but with some collagen. It is provided with vasa vasorum and lymphatic vessels too.

Front 76

elastic arteries: tunica intima

Back 76

• Tunica Intima: Thicker than in muscular arteries and appears paler than the media. Many fenestrated elastic laminae and elastic fibers lie in the subendothelial layer between the endothelium and the internal elastic lamina. Smooth muscle cells and fibroblasts are also present.

Front 77

elastic arteries: tunica media

Back 77

A thick wall of many fenestrated elastic membranes interleaved with smooth muscle cells and an indistinct external elastic lamina.

Front 78

elastic arteries: tunica adventitia

Back 78

This is thin, and is composed mostly of elastic and collagen fibers. It is provided with vasa vasorum and lymphatic capillaries.

Front 79

arterioles

thick or thin walls?
-intima is ?
-media is?
-adventitia is?

Back 79

Wall is thick relative to the lumen & is almost as wide as the diameter of the lumen.
•Intima is endothelium and basal lamina apposed to the internal elastic membrane.
•The media is only one to two layers of smooth muscle cells.
•The adventitia is only a few elastic & collagen fibers, and both elastic laminae may be lacking

Front 80

capillaries
-in most of the body endothelial cells are interconnected by ?
-in most of the brain endothelial cells are interconnected by ?
-in

Back 80

•Capillaries in most of the body: endothelial cells are interconnected by fascia occludens.
•In most of the brain: endothelial cells are interconnected by zonula occludens.

•Capillaries may be continuous or fenestrated; however, most are continuous.
•Fenestrated capillaries are found in most endocrine organs and the connective tissue of the absorptive lining of the intestine.
•Thin membranes fill these openings except in renal glomerular capillaries.

Front 81

pericyte is?

Back 81

•are intimately associated with the basal lamina of endothelial cells.
-is a mesenchymal-like cell, associated with the walls of small blood vessels. As a relatively undifferentiated cell, it serves to support these vessels, but it can differentiate into a fibroblast, smooth muscle cell, or macrophage as well if required.

Front 82

sinusoids are?

Back 82

are thin-walled, capillary-like venous blood vessels with an unusually wide lumen and an associated population of macrophages.
•They are common in myeloid tissue, the spleen, and the liver.

Front 83

venous system
• Postcapillary venules

Back 83

appear similar to capillaries, a thin endothelium surrounded by reticular fibers & pericytes.

Front 84

medium-sized veins

Back 84

the tunica adventitia is the thickest tunic, smooth muscle of the media is loosely organized & associated with collagen fibers.

Front 85

large veins

Back 85

Most large veins, except major vessels lack a t. media. They have a thick subendothelial layer and t. adventitia.

Front 86

lymphatic system
-a separate part of what system?
-it is a body wide network of ?
-it's role is to?
-collected lymph empties into the ? via the ?

Back 86

•a separate part of the circulatory system.
• It is a body-wide network of vessels with closely associated masses of encapsulated lymphoid tissue called lymph nodes.
• Its role is to withdraw excess tissue fluid from the intercellular fluid compartment, filter this through lymph nodes and return it to the blood.
• The collected lymph empties into the junction of the subclavian and internal jugular veins on the left and right sides of the body via the thoracic duct and the right lymphatic duct respectively.

Front 87

lymphatic capillaries
-they resemble ?
with these exceptions:
1. does not have a complete or any ?, which therefore...
2. one end of the capillaries ends ?
-matrix fibers hold vessels ? in face of ?

Back 87

• They resemble blood capillaries except:
• Interstitial macromolecules may pass into the lumen due to an incomplete or absent basement membrane.
• One end of lymphatic capillaries ends blindly.
• Fine extracellular matrix fibers hold the vessels open in the face of edema

Front 88

edema is?

Back 88

the increase of interstitial fluid in any organ — swelling

Front 89

lymphatic vessels
-resemble?
-do not have?
-made up of what tissues?
-which vessels have tunics?

Back 89

• They resemble small or medium-sized veins.
• Red blood cells are absent, but a few lymphocytes may be present.
• Small lymphatics have an endothelium and a thin connective tissue coat of loose connective tissue.
• Medium and large-sized vessels have 3 tunics, but they are hard to discern.

Front 90

the heart
-the heart wall is made up of ? similar to that of ?
-walls are primarily made up of ? and ?
-? is usually considered part of the pericardium.

Back 90

• The heart wall is made up of three layers or tunics, in some ways similar to that of the vessels.
• The walls of the heart are primarily made up of myocardium and endocardium.
• The epicardium is usually considered part of the pericardium.

Front 91

endocardium
-is the equivalent of which tunica?
-lines ?
-consists of ? and ? with underlying ? tissues and ? cells

Back 91

: The equivalent of the tunica intima.
• It lines the chambers of the heart, covers its various one-way valves, and is in continuity with the tunica intima of vessels entering or leaving the heart.
• It consists of a layer of endothelium and basement membrane, with underlying loose and then deeper dense connective tissue, followed by fat cells.

Front 92

Myocardium
-constructed primarily of ?
-the endomysial loose connective tissue supplies them with ?
-the branching chains of muscle cells are joined by ? junctions
-the junctions allow ?

Back 92

This is primarily constructed of cardiac muscle fibers.
• The endomysial loose connective tissue lying between muscle fibers supplies them with abundant capillaries and lymphatics.
• The branching chains of muscle cells are joined end to end by intercalated disks with adhering and gap junctions.
• The adhering junctions counteract cell separation and the gap junctions allow direct electrical continuity for the excitation waves.

Front 93

epicardium
-relative to which tunica layer?
-consists of ?

Back 93

corresponds to the tunica adventitia.
• It consists of a layer of fibroelastic connective tissue with blood and lymph vessels, nerves, and fat tissue that merges with the endomysium of the myocardium.
• This is overlain with a superficial meso- thelium of squamous epithelial cells.

Front 94

pericardium and epicardium
-the heart is enclosed by ?
-serous pericardium lines ?

Back 94

•The heart is enclosed by a 2-layered sac of connective tissue, the pericardium, with a fibroelastic outer layer, the fibrous pericardium, and an inner delicate mesothelial lining, the serous pericardium.
• The latter reflects over the surface of the heart as the epicardium or visceral serous pericardium. The serous pericardium lining the fibrous pericardium is called the parietal serous pericardium.

Front 95

SINOATRIAL & ATRIOVENTRICULAR NODES
& AV BUNDLE consists of ?

Back 95

• The SA and AV nodes are small masses of specialized cardiac muscle fibers and associated fibroelastic connective tissue.
• Both nodes are supplied with efferent postganglionic fibers from both autonomic divisions.
-• The AV Bundle (of His) consists of specialized cardiac muscle fibers that enter the interventricular septum, branch and become Purkinje fibers.

Front 96

purkinje fibers
-are located ?
-contain few ?
-have a central core around the nucleus that contains ?

Back 96

• They lie in the deepest layer of the endocardium.
• They are wider than ordinary ventricular fibers.
• They contain fewer myofibrils.
• They have a pale wide central core around the nucleus that contains much glycogen

Front 97

cardiac valves
-heart valve is ? and is vascular or avascular ?
-which fibers are present?

Back 97

• Each ventricle has inlet and outlet valves, both of the flap (leaflet) type.
• The heart valve leaflet is an intimal sheet with a core of dense irregular connective tissue that is mostly avascular.
• Elastic fibers are present.
• The fibrous core is attached to the cardiac skeleton.

Front 98

the immune system is composed of ?
-tissues are placed ?

Back 98

•Lymphatic Organs and Tissues
-tissues are places where the lymphocytes proliferate, differentiate, and mature.
-

Front 99

lymphocytes become immunocompetent where ?

Back 99

• In the thymus, bone marrow, and gut-associated lymphatic tissue (GALT)

Front 100

immunocompetent cells can ?

Back 100

can distinguish between “self” (molecules normally present within an organism) and “nonself” (foreign molecules).

Front 101

immune defenses are either:
1. non-specific
2.specific

Back 101

• These consist of physical barriers, e.g. the skin and mucous membranes, or:
1• Various chemical substances that neutralize foreign cells
2• The antibody or humoral response: The production of proteins that mark invaders for destruction by other immune cells.
• The cellular immune response: This targets transformed and virus-infected cells for destruction by lymphocytes.

Front 102

Lymphocyte T cells
-originate from ?
-there are ?% of blood lymphocytes
-how many types ?
-destroy antigens by activating ? cells

Back 102

• T lymphocytes arise from lymphocytes that are carried from the bone marrow to the thymus gland, where they mature and become immunocompetent.
• They are 60-80% of blood lymphocytes.
• There are 4 main types of T lymphocytes.
• T lymphocytes destroy antigens by cytotoxic action or by activating B-cells.

Front 103

B Cells
-comprise ?% of blood lymphocytes?
-are involved in?
-become immunocompentent where?

Back 103

• They comprise 20-30% of blood lymphocytes.
• They are involved in the production and secretion of circulating antibodies (immunoglobulins).
• They mature and become immunocompetent in the bone marrow and the GALT

Front 104

Natural Killer cells
-develop from?
-comprise ?% of blood lymphs
-recognize ?
-release ? which make these cells ?

Back 104

• Develop from same precursors as the others.
• Constitute 5-10% of blood lymphocytes.
• Genetically programmed during develop-ment to recognize virus-infected or tumor cells.
• They release perforins and fragmentins which induce these cells to self-destruct

Front 105

antigen presenting cells
-function?
-most APCs are ?nuclear ?

Back 105

• Interactions of antigens directly with B and T lymphocytes is not sufficient to destroy the antigen.
• APC’s break down antigens to peptides which bind to MHC II molecules, and the complex is displayed on the plasma membrane of the APC.
• Now the immune process can proceed.
• Most APC’s are mononuclear phagocytes.

Front 106

diffuse lymphatic tissue
-lymphocytes and other cells are located where?
-what does the presence of eosinophils and plasma cells indicate?

Back 106

The alimentary canal, respiratory passages, and genito-urinary tract are guarded by accumulations of lymphatic tissue not enclosed by a capsule.
-• Lymphocytes and other cells of this system are located in the lamina propria of these tracts.
-• Plasma cells and eosinophils in this tissue indicates antibody production and chronic inflammation and hypersensitivity respectively

Front 107

primary lymphoid organs
•Fetal Liver
•Prenatal & Postnatal Bone Marrow
•Thymus

Back 107

• These lymphoid organs are responsible for the development and maturation of lymphocytes into mature immuno- competent cells, not to facilitate immune responses.

Front 108

2ndary lymphoid organs

Back 108

•Lymph Nodes
•Spleen
•Mucosa Associated Lymphoid Tissue (MALT and GALT)
•Postnatal Bone Marrow

Front 109

thymus
-is a ? that lies mostly in the ?, but early on may extend into the ?

Back 109

• This is a bilobed endocrine gland that lies mostly in the superior mediastinum, but early on may extend into the anterior mediastinum.

Front 110

thymus
-during childhood is it active or inactive?
-from puberty to old age, it undergoes ? and produces more or less T cells?

Back 110

During childhood it is very active, but from puberty to old age undergoes progressive atrophy and produces declining numbers of T cells.

Front 111

thymus produces and contains ? that support proliferation and differentiation of ?
-also contains ? of ? epithelial reticular cells

Back 111

• The thymus also produces a number of hormones that support proliferation and differentiation of T cell progenitors (prothymocytes).
- • It contains densely packed differentiating T cells, as well as a loose network of thymic epithelial reticular cells (-supported by a connective tissue capsule)

Front 112

The outer region of the thymus is the cortex,which produces ?
-•The epithelial reticular cells of the cortex form three populations, which differentiate ?
and they leave the thymus via ? venules and ? lymphatics.

Back 112

• The cortex produces three hormones, thymosin, thymulin, and thymopoietin and some differentiation-inducing cytokines
-Types I, II, and III.

-• T cells differentiate in the cortex in response to the hormones.
-• Many of them pass into the medulla for further selection and maturation.
• T cells leave the thymus via medullary venules and efferent lymphatics.

Front 113

the inner region of the thymus is the ? and the epithelial cells within it are arranged in ? structures called ?

Back 113

• In the thymic medulla, the epithelial cells are partly arranged in spherical structures called thymic (Hassal’s) corpuscles.

Front 114

thymus is incompletely divided into ?

Back 114

incompletely subdivided into lobules by trabeculae that extend inward from the capsule.

Front 115

Type I cells of the cortex

Back 115

separate the capsule and trabeculae from the cortex and surround cortical vascular elements.
• The cells form occluding junctions with each other to isolate the cortex from the remainder of the body

Front 116

Type II cells of the cortex

Back 116

form desmosomal junctions with each other to form small compartments full of lymphocytes.

Front 117

Type III cells

Back 117

form occluding junctions that isolate the cortex from the medulla.
• These isolation measures are intended to prevent differentiating T cells from encountering foreign antigens until they are needed to react to an invader.
• The medulla stains lighter because it has mostly large lymphocytes, but has 3 more types of epithelial reticular cells.

Front 118

Types IV and V have ? roles

Back 118

structural

Front 119

Type VI is the ?, whose function is unknown

Back 119

• Type VI is the Hassal’s corpuscle, whose function is unknown.

Front 120

• The loose connective tissue of the epithelial linings of the digestive, respiratory, and urinary tracts commonly contains

Back 120

lymphoid follicles and nodules

Front 121

lymphoid follicles are mostly ? in size, dependent or independent, and discrete or indiscrete?

Back 121

Most are small, solitary and discrete.

Front 122

•At some places, lymphoid follicles are large, multiple and confluent.
•Places with large aggregates of follicles include:

Back 122

• The Tonsils
• Peyer’s Patches
• The Appendix

Front 123

large lymphoid follicular aggregations receive ? that penetrate ? and diffuse through the ?

Back 123

• Permanent large aggregations like this receive foreign antigens that penetrate the epithelium and diffuse through the lamina propria.

Front 124

a preliminary stage in the production of antibody-producing plasma cells:

Back 124

•The epithelia of the tonsils, Peyer's Patches, the Appendix contain flat epithelial cells (M cells or FAE cells) that ingest antigen and deliver them to APC’s of the GALT.

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lymph nodes are ? shaped structures with 3 things:

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• Kidney-shaped structures with a capsule, cortex, and medulla.

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lymph node cortex contains ? and ? passes to the medulla
-follicles that contain ? cells are present in the ? zone of the cortex
-the ? cortex, the deeper cortex, contains ? cells

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• Cortex contains follicles & B cell progeny pass to the medulla
-• B cell containing follicles are present in the outer zone of the cortex.
-•The deeper cortex (paracortex) contains T cells.

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•in lymph nodes, Numerous macrophages remove

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bacteria and particulate matter.

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? lymph vessels penetrate the capsule, ? lymph vessels leave the ?

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• Afferent lymph vessels penetrate the capsule, efferent lymph vessels leave the hilum (the junction at which the splenic vessels enter and leave the organ)

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? centers are sites of antigen-elcited B cell proliferation
-•Also present here are ? cells, a type of APC.

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•Germinal centers
-follicular dendritic cells

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these contain large numbers of plasma cells that live there for 3 days and release their antibodies into the efferent lymph:

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•Medullary cords

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? cells are also found in the medullary cords
-? cells are formed from activated ? cells in the cortex

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• Some B cells are also found there.
•Plasma cells are formed from activated B cells in the cortex.

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the spleen is ?
-like the thymus, it contains only ? lymphatics
-it has a loose or dense fibroelastic capsule?
-islands of white pulp are scattered within ? and are primarily ?
-red pulp is full of ? and serves as ?

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•The largest lymphoid organ.
•Like the thymus, it contains only efferent lymphatics.
•It has a dense fibroelastic capsule.
•It has red pulp, internally supported by reticular fibers and appears bright red.
•Islands of white pulp are scattered through the red pulp.
•Islands of white pulp are primarily lymphoid follicles.
•The red pulp is full of erythrocytes and serves as a blood filter.

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the spleen/red pulp cleans out:
and the internal circulatory system is a unique

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It removes:
• Worn out blood cells
• Platelets
• Suspended particulate matter.
• The internal circulation is a unique open system.

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red pulp is composed of ? and functions

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"sinuses" (or "sinusoids") which are filled with blood
* "splenic cords" of reticular fibers
* "marginal zone" bordering on white pulp
-Removes unwanted materials from the blood, including senescent red blood cells.

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white pulp is composed of ? and functions to ?

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Composed of nodules, called Malpighian corpuscles. These are composed of:
* "lymphoid follicles" (or "follicles"), rich in B-lymphocytes
* "periarteriolar lymphoid sheaths" (PALS), rich in T-lymphocytes Helps fight infections.

Other functions of the spleen
-helps to fight infection

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does the spleen create RBCs?

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yes and...
Production of opsonins, properdin, and tuftsin.
Creation of red blood cells. While the bone marrow is the primary site of hematopoeisis in the adult, up until the fifth month of gestation, the spleen has important hematopoietic functions.

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spleen's chief functions:
-formation of ? and destruction of ?

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• Antibody formation: splenic B cells make lots of plasma cells. It is the chief source of circulating antibodies.
• Disposal of defective red blood cells.