Functional lymphoid anatomy Flashcards Preview

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Flashcards in Functional lymphoid anatomy Deck (34):
1

Stromal cells

Provide signals that direct the development of progenitor cells and eventually B cells

2

Where do the final stages of B cell development occur?

In the periphery

3

Central tolerance

Immature B cells are tested in the bone marrow to test for self-reactivity

4

Course of B cells out of the bone marrow

Leave via sinusoids that enter the central sinus and are carried by veins to the spleen

5

Where/when do T cells develop?

In the thymus; migrate there as progenitor cells during embryogenesis

6

How are T cell numbers maintained?

Through long-lived T cells and division of mature T cells outside the central lymphoid organs

7

Thymic cortex

On the outside of the thymus; only contains immature T cells and most maturation happens here

8

Corticomedullary junction

Where T cell progenitors enter

9

Thymic medulla

Inner region where more mature single-positive T cells, as well as macrophages and dendritic cells

10

Thymic cortical stroma

Network of epithelium where the developing T cells reside; they have both MHCI and MHCII on them

11

Double-negative cells

The first portion of T cells have no CD3 or CD4/8 expression

12

Double-positive cells

As the T cells continue to move toward the medulla, they undergo receptor rearrangement until they are positive on all three

13

What happens if the double-positive cell does not recognize self-peptide:self-MHC?

They undergo apoptosis

14

What percentage of T cells die in the thymus?

98%

15

Positive selection

If the double-positive cell can recognize the self-peptide:self-MHC complex, then it will survive, drop a positive, and become either CD3+CD8+ or CD3+CD4+ and migrate to the medulla

16

Negative selection

If the single-positive cell recognizes the self-MHC:self-antigen complex too strongly, then it will be killed. If not, it can migrate out of the medulla and into the periphery

17

Peripheral lymphoid tissues

Aggregations of lymphocytes in non-leukocytic stromal cells that give out survival signals

18

Basic principles of peripheral lymph tissues

Trap the APCs and antigens in the same area as the lymphocytes so a secondary response can be elicited
Keep the lymphocytes that didn't encounter their antigen alive so they can recirculate

19

What mediates the homing of lymphocytes

Chemokines

20

How long does it take for the adaptive immune system's effects to be seen?

1 week

21

Steady state

When naive lymphocytes don't meet their match, they will recirculate until they do find their match or they die

22

High endothelial venules

In the paracortical areas; how the naive lymphocytes get into the lymph node

23

Follicles of lymph node

Where B cells are located in a lymph node

24

Cortical area of lymph node

Outer portion of the lymph node, where the follicles are

25

Paracortical area of lymph node

Deep cortex where T lymphocytes are

26

Passage of lymphocytes through the spleen

Enter in the marginal sinus of the red pulp, leave through the white pulp

27

PALS

Periarteriolar lymphoid sheath; mainly T cells

28

Follicles of the spleen

Next to the PALS; could be germinal centers,

29

Marginal zone of the spleen

Surrounds follicle; contains macrophages and resident, non-circulating B cells

30

GALT

Collect antigen from the endothelial gut tract

31

Microfold cells

Directly collects antigen from the lumen

32

B cells in the gut produce what antibodies?

IgM, but mostly IgA

33

BALT

In the bronchus/airway

34

What enzymes and antibodies are produced by BALT?

Defensin, IgM, IgA, IgG