Lymphoid Organs

Question 1

macrophages and dendritic cells

Answer 1

APCs

Question 2

bone marrow, thymus, production of lymphocytes

Answer 2

primary/central lymphoid organs

Question 3

lymph nodes, spleen, tonsils, Peyer’s patches, microenv for lymphocytes and antigens

Answer 3

secondary/peripheral lymphoid organs

Question 4

(primary/secondary) lymphoid nodules have germinal centers

Answer 4

secondary

Question 5

loose lymphoid tissue

Answer 5

retucular cells

Question 6

dense lymphoid tissue

Answer 6

lymphocytes

Question 7

what happens in dark zone of germinal center

Answer 7

clonal expansion of B cells

Question 8

mantle zone of germinal center

Answer 8

storage of young plasma and memory B cells

Question 9

what happens in light zone of germinal center

Answer 9

• (+/-) selection of B cells

- differentiation of (+) selected B cells

Question 10

where are lymphatic nodules located in the lymph nodes

Answer 10

cortex

Question 11

medullary sinuses in lymph node

Answer 11

• no epithelial lining, loose lymphoid tissue

- permeable walls - free passage of wandering cells

Question 12

efferent lymphatics

Answer 12

• leave node at hilus

- valves point away from hilus

Question 13

afferent lympatics

Answer 13

• enter node at multiple sites on convex surface

- valved open toward node

Question 14

path of lymph through node

Answer 14

afferent lymphatics –> subcapsular sinus –> peritrabecular (intermediate) sinuses –> medullary sinuses –> efferent lymphatics

Question 15

reticular cells in lymph nodes

Answer 15

phagocytes

-failure leads to spread of infection, metastases

Question 16

where is lymph filtered

Answer 16

sinuses of node

Question 17

lymphocytes are produced in

Answer 17

germinal centers

Question 18

lymphocyte circulation once produced

Answer 18

production in gemrinal centers –> forces to periphery of nodules –> enter sinuses –> leave node via efferent lymphatics –> enter circ system via throracic duct

Question 19

lymphocytes enter circulatory system via

Answer 19

thoracic duct

Question 20

how does most lymph return to nodes

Answer 20

high endothelial venules (HEVs) (post-capillary venules)

Question 21

Where are HEVs found (high endothelial venules)

Answer 21

lymph nodes, Peyer’s patches, tonsils

-NOT spleen

Question 22

return lymph to node, permeable to small lymphocytes, cell adhesion molecules

Answer 22

HEVs

Question 23

most HEVs are found here, populated mostly by T lymphocytes, under thymin influence

Answer 23

boundary between cortex and medulla

-paracortical zone AKA deep/tertiary/inner cortex

Question 24

where are deep cortex units

Answer 24

openings of afferent lymphatic

Question 25

central vs peripheral deep cortex regions of lymph node

Answer 25

storage/prolif vs HEVs/migration of lymphocytes

Question 26

functions of paracortical zone

Answer 26

filter lymph, produce and select B lymphocytes, immune response to lymph-born antigens

Question 27

embryological origin of thymus

Answer 27

- 3rd and 4th branchial/pharyngeal pouches | - mesenchyme

Question 28

site of thymocyte proliferation, apoptosis, and selection

Answer 28

cortex of thymus

Question 29

site of thymocyte maturation

Answer 29

medulla of thymus

Question 30

epithelial reticular cells do not....

Answer 30

- not phagocytic | - do not manufacture reticular fibers

Question 31

epithelial reticular cells in thymus secrete

Answer 31

thymosins - pomote differentiation of T cells

Question 32

epithelial reticular cells form

Answer 32

Hassall's corpuscles

Question 33

what structures are unique to thymic medulla, concentrically arranged around epithelial reticular cells, kertinize/calcify, contributes to blood-thymus border, and decrease with age

Answer 33

Hassall's corpuscles

Question 34

where are desmosomes and tonofilaments found in the thymus

Answer 34

epithelial reticular cells

Question 35

reticular cells of mesenchymal origin

Answer 35

dendritic cells

Question 36

dendritic cells of thymus are identical to

Answer 36

reticular cells of lymph node | -phagocytic

Question 37

dendritic cells produce

Answer 37

thymopoietin (induction of CD90)

Question 38

dendritic cells support development of T lymphocytes under influence of

Answer 38

thymosin

Question 39

where is largest accumulation of lymph in the body

Answer 39

spleen

Question 40

where is smooth muscle in spleen

Answer 40

capsule and trabeculae

Question 41

red splenic pulp

Answer 41

splenic sinuses and splenic cords

Question 42

splenic cords and splenic sinuses

Answer 42

cords are between sinuses

Question 43

splenic sinuses

Answer 43

vascular channels, discontinuous basement membrane with macrophages for free exchange btw cords and sinuses

Question 44

splenic cords

Answer 44

cellular tissue between sinuses, destruction of RBCs, storage of blood

Question 45

RBCs destroyed and blood is stored here in sleen

Answer 45

splenic cords

Question 46

composed of lymphoid tissue, periarterial lymphatic sheath (PALS), lymphatic nodules

Answer 46

white splenic pulp

Question 47

junction of red and white splenic pulp, contains lymphocytes, dendritic cells, macrophages, site of initiation of immune responses to blood-born antigens

Answer 47

marginal zone

Question 48

blood flow through slpeen

Answer 48

splenic artery enters at hilus --> trabecular arteries --> central arteries/arterioles --> penicilli --> capillaries

Question 49

what artery enters hilus of spleen

Answer 49

splenic

Question 50

theory that states splenic capillaries go to cords then sinuses = slower

Answer 50

open theory

Question 51

theory that splenic capillaries go straights to sinuses (bypass cords) = faster

Answer 51

closed theory

Question 52

penicilli

Answer 52

branches into splenic red pulp

Question 53

in spleen, structures that are spaces between endothelial cells, have discontinuous basement membrane with macrophages within cords

Answer 53

splenic sinuses

Question 54

where are lymphocytes produced in the spleen

Answer 54

secondary lymphatic nodules

Question 55

immune response to blood born antigens in spleen

Answer 55

dendritic cells present antigen to lymphocytes --> activated B cells migrate to lymphatic nodules, differentiate --> activated T cells migrate to PALS, differentiate