Immune II

Question 1

describe MALT

Answer 1

mucosal-associated lymphoid tissue, nodules that are important in organs that are open to the external environment /high risk of pathogenic invasion

Question 2

where are MALT cells found

Answer 2

digestive, respiratory, urinary, genital

Question 3

what to MALT aggregates make

Answer 3

tonsils, appendix, peyers patches

Question 4

describe MALT

Answer 4

unencapsulated, lack collagenous capsule (may be covered in flattened reticular cells)

Question 5

2 major components of MALTS

Answer 5

1. GALTS (gut associated lymphoid tissue)

2. BALTS (bronchus associated lymphoid tissue)

Question 6

describe GALT

Answer 6

in small intestines as peyer’s patches, in lamina propria below mucosa, LYMPHOID NODULES FORM HALF CIRCLE (CLUMP)

Question 7

describe Peyer’s patches

Answer 7

large, unencapsulated aggregates in walls of ileum, clumps/dozens of lymphoid nodules in lamina propria of mucosa and extends into submucosa

Question 8

what cells cover peyers patches

Answer 8

simple columnar, follicle associated epithelium (FAE), contain microfold cells that can sample the antigen directly from the lumen

Question 9

functions of peyer’s patches

Answer 9

1. immune surveillance of interstitial lumen

2. facilitate immune response in mucosa

Question 10

what do microfold (M) cells do

Answer 10

sample antigens directly from lumen

Question 11

describe GALT in the appendix

Answer 11

surround entire lumen, goblet cells within epithelium, also has microfold cells, lymphoid nodules within lamina propria, NO VILLI

Question 12

compare GALT in appendix and ileum

Answer 12

ileum has VILI with simple columnar epithelium and microvili, appendix has microvilli (simple columnar epi) but NO VILI

Question 13

describe palatine tonsils

Answer 13

1. covered in stratified squamous epithelium NOT KERATINIZED
2. 10-20 CRYPTS
3. numerous lymphatic nodules - GALT - B cells, plasma cells, macrophages, surrounding nodules are T cells
4. band of dense CT separates tonsil from underlying tissue = barrier against spread of infections

Question 14

describe lingual tonsils

Answer 14

1. covered in stratified squamous epithelium NOT KERATINIZED
2. SINGLE crypt
3. numerous lymphatic nodules
4. may see muscle and mucosal cells

Question 15

describe pharyngeal tonsils

Answer 15

1. covered by ciliated pseudostratified columnar epithelium
2. NO CRYPTS
3. lymphatic nodules
4. thick respiratory folds, mucosa

Question 16

describe lymph nodes

Answer 16

continuous encapsulated lympoid nodules, small but numerous, has cortex, medulla, capsule, afferent lymph vessels and efferent lymph vessels, blood capillaries/artery/vein in hilum

Question 17

composition of cortex and medulla of lymph nodes

Answer 17

cortex: mostly B cells, nodules are here
paracortex: mostly T cells
medulla: lighter,macrophages, and plasma cells
medullary sinus: below medulla ans plasma cells and macrophages circulate here

Question 18

describe capsule of lymph node

Answer 18

1. dense CT, abundant lymphatics and vasculature
2. subcapsular sinus containing lymph traveling through cortex
3. cortex is deep

Question 19

what cells are found in cortex of lymph node

Answer 19

reticular cells, macrophages, APC, lymphocytes, lymphoid nodules of mostly B cells, some secondary, have cortical sinuses between nodules to connect to subcapsular sinus

Question 20

cells found in paracortex

Answer 20

mostly T cells, no lymphoid nodules and contains HEV (HIGH ENDOTHELIAL VENULES)

Question 21

what are HEV

Answer 21

IN PARACORTEX OF LYMPH NODES, high endothelial venules, entry site for lymphocytes moving from blood into lymph node, have dome like projections with spaces where T and B cells squeeze in

Question 22

contents of medulla

Answer 22

1. medullary cords

2. medullary sinuses

Question 23

composition of medullary cords

Answer 23

consists of mainly plasma cells and macrophages, plasma cells are resident and secrete Ab into circulation, branched extension of lymphoid tissue

Question 24

composition of medullary sinuses

Answer 24

spaces separate medullary cords that contain reticular cells, fibers, lymph, lymphocytes, macrophages, ARE CONTINUOUS WITH CORTICAL SINUSES AND HILUM TO DELIVER LYMPH TO EFFERENT VESSELS

Question 25

describe flow of lymph through node

Answer 25

flow into afferent lymphatic vessels into subcapsular sinus, into cortical sinuses, infiltrate between cortex and medullary cords, into the medullary sinuses into the hilum/efferent lymphatics