Functional Lymphoid Anatomy Flashcards Preview

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Flashcards in Functional Lymphoid Anatomy Deck (19)
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1
Q

What is central lymphoid tissue?

A

Bone Marrow

Thymus

2
Q

What is peripheral lymphoid tissue?

A

Spleen

Lymph Nodes

3
Q

What is the function of central lymphoid tissue?

A
  • Responsible for lymphopoiesis

* Responsible for central tolerance

4
Q

What is the function of peripheral lymphoid tissue?

A
  • Mixture of B & T cells
  • Supports circulating lymphocyte survival
  • Activation of naïve lymphocytes
  • Peripheral tolerance
5
Q

What is the function of the bone marrow?

A

All lymphocytes develop from HSCs in the bone marrow

6
Q

What factors does B cell development depend on?

A

Progression of B cell development depends on factors made by stromal cells:

  • IL-7
  • FLT3 Ligand
  • SCF (stem cell factor)
  • CXCL12
7
Q

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

A

They move toward the central sinus of the

marrow cavity, then into circulation, bound for the peripheral lymphoid organs

8
Q

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

A

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
Q

What is found in the thymic cortex?

A

Cortex: contains only immature thymocytes & scattered macrophages

10
Q

What is found in the thymic medulla?

A

Medulla: more mature thymocytes, dendritic cells & macrophages

11
Q

What role does central tolerance play in T cells?

A

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

12
Q

What attracts lymphocytes into the paracortical area of lymph nodes?

A

Chemokines

13
Q

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

A

Double negative (CD3+) cells are formed

14
Q

What occurs in the deep cortex of the thymus?

A

Immature double positive cells are formed

15
Q

What occurs in the medulla of the thymus?

A

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

16
Q

What is the function of the spleen?

A

Responds to bloodborne pathogens and recycles RBCs

17
Q

What is the red pulp of the spleen?

A

Site of RBC disposal

18
Q

What is the white pulp of the spleen?

A

Collections of densely packed lymphocytes are found here

19
Q

What is peripheral tolerance?

A

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.