Functional Lymphoid Anatomy Flashcards Preview

Immunology > Functional Lymphoid Anatomy > Flashcards

Flashcards in Functional Lymphoid Anatomy Deck (19):
1

What is central lymphoid tissue?

Bone Marrow
Thymus

2

What is peripheral lymphoid tissue?

Spleen
Lymph Nodes

3

What is the function of central lymphoid tissue?

• Responsible for lymphopoiesis
• Responsible for central tolerance

4

What is the function of peripheral lymphoid tissue?

• Mixture of B & T cells
• Supports circulating lymphocyte survival
• Activation of naïve lymphocytes
• Peripheral tolerance

5

What is the function of the bone marrow?

All lymphocytes develop from HSCs in the bone marrow

6

What factors does B cell development depend on?

Progression of B cell development depends on factors made by stromal cells:
-IL-7
-FLT3 Ligand
-SCF (stem cell factor)
-CXCL12

7

Where do the B cells move as the mature in the bone marrow?

They move toward the central sinus of the
marrow cavity, then into circulation, bound for the peripheral lymphoid organs

8

How does central tolerance play a role in B cell development?

Self-reactive B cells will die by apoptosis.

Soluble self with cross linking self molecules
are made anergic but do go to the periphery

9

What is found in the thymic cortex?

Cortex: contains only immature thymocytes & scattered macrophages

10

What is found in the thymic medulla?

Medulla: more mature thymocytes, dendritic cells & macrophages

11

What role does central tolerance play in T cells?

T cells will recognize Ag-MHC but only become activated when the Ag is NOT self

12

What attracts lymphocytes into the paracortical area of lymph nodes?

Chemokines

13

What occurs in the outer cortex/subcapsular area of the thymus?

Double negative (CD3+) cells are formed

14

What occurs in the deep cortex of the thymus?

Immature double positive cells are formed

15

What occurs in the medulla of the thymus?

Positive selection of the DP cells and negative selection of the SP cells that will generate cells with central tolerance.

16

What is the function of the spleen?

Responds to bloodborne pathogens and recycles RBCs

17

What is the red pulp of the spleen?

Site of RBC disposal

18

What is the white pulp of the spleen?

Collections of densely packed lymphocytes are found here

19

What is peripheral tolerance?

In the absence of an infection, mature B & T cells that encounter strongly crosslinking Ag in peripheral lymphoid organs will undergo clonal deletion or anergy.