Histo - 9 Lymphatic System

Front 1

structures that produce the cell components of the immune system

Back 1

primary lymphoid organs

Front 2

examples of primary lymphoid organs

Back 2

bone marrow and thymus

Front 3

in these organs, lymphocytes differentiate from lymphoid stem cells, proliferate and mature into functional cells

Back 3

primary lymphoid organs

Front 4

structures that are the sites to trap antigen from defined tissues or vascular spaces where immune responses occur

Back 4

secondary lymphoid organs

Front 5

examples of secondary lymphoid organs

Back 5

lymph node, spleen, tonsils and aggregates of lymphocytes and antigen-presenting cells in lung and mucosa of digestive track

Front 6

major cells of the lymphatic system

Back 6

lymphocytes and macrophages

Front 7

cells found in peripheral blood, lymph nodes, spleen, thymus, tonsils, appendix, and scattered in many other tissues - have very little cytoplasm and round nucleus

Back 7

lymphocytes

Front 8

these cells originate in bone marrow, mature in fetal liver and bone marrow and migrate to secondary (peripheral) lymphoid organs

Back 8

B cells

Front 9

when B cells are activated, they differentiate into...

Back 9

plasma cells

Front 10

precursors of cells that produce immunoglobulins (antibodies)

Back 10

B cells

Front 11

these cells are located in CT and lymphoid tissues, but NOT found in circulation

Back 11

plasma cells

Front 12

these cells originate in bone marrow, mature in thymus, the migrate to secondary lymphoid organs like lymph nodes and spleen

Back 12

T cells

Front 13

macrophages are derived from

Back 13

blood monocytes

Front 14

macrophages in liver

Back 14

Kupffer cell

Front 15

macrophages in lung

Back 15

alveolar macrophage

Front 16

macrophages in brain

Back 16

microglia

Front 17

functions of macrophages

Back 17

phagocytosis and antigen presentation

Front 18

how are lymphatic capillary walls different from blood capillary walls?

Back 18

more permeable

Front 19

which organs lack lymphatics?

Back 19

brain, spinal cord, internal ear, cartilage, bone and bone marrow

Front 20

lymphatic vessels resemble veins with these exceptions:

Back 20

thinner walls
contain more valves
lymph nodes at intervals along course
intima, media and adventitia are poorly demarcated

Front 21

collecting vessels originate as microscopic blind-end vessels called

Back 21

lymphatic capillaries

Front 22

lymphatic valves originated by

Back 22

local folding of the tunica intima

Front 23

what are the two main lymphatic ducts?

Back 23

thoracic duct and right lymphatic duct

Front 24

structure that arises in the abdomen and travels up along vertebral column through the thorax and empties into superior vena cava

Back 24

thoracic duct

Front 25

structure that is short and carries drainage from the right upper portion of the body

Back 25

right lymphatic duct

Front 26

dense localized collections of lymphocytes arranged in rounded masses that are sharply defined but not encapsulated

Back 26

lymphatic nodules

Front 27

what type of lymph nodules do not have germinal centers

Back 27

those that are in a state of rest

Front 28

primitive reticular cells give rise to what?

Back 28

medium sized lymphocytes in addition to macrophages

Front 29

4 functions of lymphatic nodule

Back 29

1. production of new lymphocytes
2. functional differentiation of B lymphocytes
3. phagocytic potential of free and fixed macrophages
4. activity against bacteria and foreign matter

Front 30

aggregate nodules are a close grouping of lymph nodules that are present in lamina propria and are also called what?

Back 30

peyer's patches

Front 31

the top of the peyer's patch nodule facing the lumen is covered with what/

Back 31

intestinal epithelium

Front 32

aggregates of more or less encapsulated lymphatic tissue situated at the entrance of the oral and nasal pharynx

Back 32

tonsils

Front 33

structure located at the entrance to the throat

Back 33

palatine tonsil

Front 34

the palatine tonsil is composed of what types of tissue?

Back 34

diffuse and nodular lymphoid tissue

Front 35

what covers the free surface of the palatine tonsil?

Back 35

non-keratinized stratified squamous epithelium

Front 36

what lines the lingual tonsil?

Back 36

non-keratinized stratified squamous epithelium

Front 37

leukocyte infiltration is less in the lingual tonsil than in what?

Back 37

palatine tonsil

Front 38

clinical name for pharyngeal tonsils

Back 38

adenoids

Front 39

location of pharyngeal tonsils

Back 39

median dorsal wall of the nasopharynx

Front 40

epithelium of pharyngeal tonsils

Back 40

pseudostratified with cilia and goblet cells

Front 41

oval-shaped structures occurring in series along the lymphatic vessels

Back 41

lymph nodes

Front 42

what extends from the covering capsule of lymph nodes to the center of the node?

Back 42

fibrous septa or trabeculae

Front 43

trabeculae in lymph nodes separates what from each other?

Back 43

cortical nodules

Front 44

what lines both the cortical and medullary sinuses of lymph nodes?

Back 44

reticular cells and macrophages capable of phagocytosis

Front 45

cellular component/lymphoid tissue of lymph node

Back 45

parenchyma

Front 46

portion of cortical parenchyma that is adjacent to medulla and is free of nodules

Back 46

deep cortex, paracortex, or thymus-dependent cortex

Front 47

area of lymph node where lymphoid tissue is found in dense strands or cords

Back 47

medullary parenchyma

Front 48

medullary parenchyma is the chief site of what 3 structures?

Back 48

B lymphocytes, macrophages and plasma cells

Front 49

where are T lymphocytes most common in lymph node?

Back 49

paracortex (deep cortex)

Front 50

system of irregular channels lined with reticular cells

Back 50

lymphatic sinuses

Front 51

3 parts to the lymphatic sinus system

Back 51

subscapular sinus
trabecular sinus
medullary sinus

Front 52

the emigration of lymphocytes from the blood into the lymph nodes occurs only at these endothelial cells

Back 52

high endothelial venules

Front 53

largest of all lymphoid organs

Back 53

spleen

Front 54

2 types of parenchyma in spleen

Back 54

white pulp and red pulp

Front 55

channels that intervene between veins and arteries

Back 55

splenic sinuses

Front 56

surrounds and follows arteries, thickens into ovoid masses called splenic nodules

Back 56

white pulp

Front 57

what forms the periarterial lymphoid sheaths?

Back 57

white pulp

Front 58

PALS are mainly composed of what cells?

Back 58

T lymphocytes

Front 59

germinal centers are mainly composed of what cells?

Back 59

B lymphocytes

Front 60

transitional area bw white and red pulp that is looser in texture than white pulp

Back 60

marginal zone

Front 61

which area of the spleen receives the incoming arterial blood?

Back 61

marginal zone

Front 62

first site for blood borne cells and particulate matter with splenic parenchyma

Back 62

marginal zone

Front 63

this area of the splenic parenchyma consists of splenic sinuses separated by splenic cords

Back 63

red pulp

Front 64

density and firmness of red pulp depends on what?

Back 64

amount of blood present

Front 65

arterial blood flow into the spleen

Back 65

splenic artery --> trabecular arteries --> central artery (supplies white pulp) --> penicillar arterioles --> arterial capillaries --> splenic cords --> splenic sinuses

Front 66

splenic sinuses conduct blood to what structure?

Back 66

pulp veins

Front 67

splenic veins are lined with what?

Back 67

conventional epithelium and continuous basal lamina

Front 68

pulp veins converge to form what?

Back 68

trabecular veins (then splenic vein)

Front 69

7 major functions of spleen

Back 69

1. form RBCs during fetal life
2. Remove and destroy damaged RBCs
3. Retrieve iron from red cell hemoglobin
4. generate lymphocytes and monocytes
5. filter blood
6. actively phagocytize bacteria
7. produce antibodies

Front 70

broad, flat bilobed mass of lymphoid tissue enclosed by a connective tissue capsule

Back 70

thymus

Front 71

first organ to become lymphoid during embryonic life

Back 71

thymus

Front 72

cortex parenchyma of the thumus consists of what cells?

Back 72

lymphocytes, reticular cells and macrophages

Front 73

this area of the thymus consists of a concentric mass of epithelioreticular cells joined together by many desmosomes

Back 73

medulla

Front 74

distinguishing feature of the thymus

Back 74

hassall's corpuscles

Front 75

isolated mass of closely packed, concentrically arranged type VI epithelioreticular cells

Back 75

hassall's corpuscles

Front 76

hassall's corpuscles produce ______ that function in differentiation and maturation of T lymphocytes

Back 76

interleukins

Front 77

what protects developing T lymphocytes from exposure to antigens?

Back 77

blood-thymus barrier

Front 78

components of blood-thymus barrier

Back 78

1. endothelium and its basal lamina
2. macrophages in perivascular tissue
3. type I epithelioreticular cells with their basal lamina

Front 79

major function of the thymus

Back 79

differentiation and proliferation of t-lymphocytes

Front 80

thymus is eventually replaced by what?

Back 80

adipose tissue

Front 81

produce antibodies in response to cell-free and cell-bound antigens

Back 81

B lymphocytes

Front 82

20-30% of circulating lymphocytes

Back 82

B lymphocytes

Front 83

60-80% of circulating lymphocytes

Back 83

T lymphocytes

Front 84

respond to cell-bound antigens (viral, fungal infected, and tumors)

Back 84

T lymphocytes

Front 85

5-10% of circulating lymphocytes

Back 85

NK (natural killer) cells

Front 86

stroma

Back 86

reticular fibers and cells

Front 87

diffuse lymphatic tissue is mainly found where?

Back 87

GI tract and respiratory tract

Front 88

sites of B lymphocyte proliferation

Back 88

germinal centers

Front 89

aggregated lymphatic nodules in ileum

Back 89

peyer's patches