Lymphoid Tissue Flashcards Preview

HDM Midterm > Lymphoid Tissue > Flashcards

Flashcards in Lymphoid Tissue Deck (27)
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1
Q

primary lymphoid organs

A
thymus and (red) bone marrow
produce lymphocytes
2
Q

secondary lymphoid organs

A

tonsils, lymph nodes (cervical, axillary, inguinal) spleen, MALT in small intestine
diffuse, lymphocytes are activated in response to Ag

3
Q

Diffuse non-encapsulated LT

A

Reticular CT houses lymphocytes deep to epithelium

GI tract, Genitourinary tract, respiratory passages

4
Q

nodular non-encapuslated LT

A

primary nodule/follicle consists of only small
lymphocytes - inactive or naive, lack a germinal center

secondary nodule == activated version thats been presented - possesses germinal center - outer ring, mantle

5
Q

germinal center

A

B cells localized to follicle, germinal center and mantle

T cells surround follicle

6
Q

Tonsils: aggregate non-encapsulated LT

A

tonsils are large, irregular masses of LT - help protect against inhaled/ingested substances - can be partially encapsulated

7
Q

palatine tonsil

A

stratified squamous epithelium
10-20 tonsillar crypts == deep invaginations
dense CT acts as partial capsule
contains germinal centers

8
Q

pharyngeal tonsil

A

pseudostratified columnar ciliated
single structure at the posterior wall of nasopharynx
thin underlying capsule
shallow infoldings, no crypts

9
Q

lingual tonsil

A

stratified squamous
base of tongue
germinal centers
lacks a capsule but has crypts

10
Q

MALT: non-encapsulated aggregate nodular LT

A

single/clusters of nodules
found in GI tract (GALT), respiratory airways (BALT) and urinary tract
lumen open to external environment

11
Q

GALT: aggregate nodular tissue

A
simple columnar with goblet cells 
gut associated lymphoid tissue - prominent in small intestine (ileum**) 
peyer patches  
characterized by an abundance of villi 
single or clusters of nodules
12
Q

veriform appendix: aggregate nodule

A

simple columnar with goblet cells
short, small projection off cecum
filled with LT
crypts - no villi, no capsule

13
Q

thymus

A

in mediastinum
lymphoblasts invade and proliferate here
lymphocytes mature into T cells
characterized by involution (decreased activity as its replaced with adipose tissue)
capsulated - lobulated by septa
contains T lymphocytes, macrophages, thymic epithelial cells

14
Q

thymic epithelial cells

A

subcapsular (squamous) - form cortical compartment - some of these will form a sheet to separate cortex and medulla
cortical (stellate) - prdocue cytoreticulum of keratin and desmosomes - secrete cytokines for T cell development

15
Q

blood-thymus barrier

A

in cortex - formed by TECs, basal lamina, endothelial cells

macrophages prevent circulating Ag from reacting with developing T cells

16
Q

thymic medulla

A

houses mature T cells migrating from cortex

T cells enter postcapillary venules to exit thymus

17
Q

Hassall’s corpuscles

A

thymic - associated with medulla
closely packed whorls of TECs
secrete cytokines that aid in maturation of T cells

18
Q

thymus compartments

A

cortex - contain T lymphocytes - subscapular TECs, cortical TECs, macrophages
at side proximal to postcapillary venule, single-positive T cells, followed by double positive and double-negative most distal
medulla - mature T cells - medullary TECs, hassall’s corpuscles, DC, Mphage

19
Q

spleen

A

initiates immune response to blood Ag
reservoir for platelets
hematopoiesis/RBC recycling center

20
Q

spleen structure

A

surrounded by CT capsule - trebeculae incompletely separate
parenchyma with reticular fibers of white and red pulp
single splenic artery and vein

21
Q

white pulp of spleen

A

T and B cells, macrophages
lymphoid nodules - central arteriole
PALS - periarteriolar lymphoid sheaths - T cells surrounding arteriole
MnA - corona/mantle - small lymphocytes surrounding GC
MgZ- marginal zone - blend of lymphocytes

22
Q

red pulp of spleen

A

contains RBCs, platelets, macrophages, plasma cells
blood filtration/RBC turnover
splenic sinusoids and splenic cords

23
Q

splenic cords

A

reticular tissue rich in macrophages and lymphocytes

24
Q

stave cells

A

line sinusoids of red pulp

specialized endothelial cells that separate healthy and unhealthy RBCs

25
Q

splenic blood flow

A

splenic artery -> trabecular arteries -> central arteriole/ PALS -> white pulp -> penicillar arteries -> splenic sinuses -> splenic cords

26
Q

lymph

A

clear, yellow fluid comprised of interstitial fluid, solutes, foreign material

27
Q

lymph nodes

A

encapsulated- positioned along lymphatic vessels
400-450
filter lymph - remove debris, facilitate Ab production, produce lymphocytes