Lymphoid tissue Flashcards
What are primary lymph tissues?
those sites that support the generation of functionally mature, but antigen naïve, T and B cells
(bone marrow and thymus)
What are secondary lymph tissues?
locations where naive lymphocytes reside while waiting to be activated by their specific antigens. These funnel antigens through them.
(e.g. Lymph nodes, Peyer’s patches, spleen)
What are tertiary lymph tissues?
sites of the body where the elimination of antigen takes place (the “battlefield”)
e.g. skin, GI, lungs, vagina
What are the cells in bone marrow responsible for the generation of new cells?
Pleuripotent stem cells
The hematopoietic compartment of the marrow is supported by what?
the bone marrow stroma
The bone marrow stroma is composed of what? (3)
reticular stromal cells, macrophages, and adipocytes
What is the function of stromal cells in the stromal tissue of bone marrow?
provide for cell-to-cell contact as well as soluble factors required for the differentiation of the hematopoietic cells
Where do B lymphocytes mature? From where to where?
Mature from outer to inner part of bone marrow
The differentiation of immature B cells to mature B cells takes place where?
Secondary lymphatic tissue
Where do T lymphocytes originate from? Where do they go to mature?
Bone marrow, go to thymus
Stem cells differentiate into what precursor of T cells?
Prothymocyte
Once in the thymus, the prothymocytes are called what?
Thymocytes
Where are autoreactive T cells deleted?
Thymus
Why does it not matter that the thymus degenerates in adults?
Once the T lymphocyte repertoire is established, T cell immunity is maintained by long-lived memory T cells and division of mature peripheral T cells.
Do thymocytes express TCR, CD3, CD4, or CD8 proteins?
No
True or false: during the development of thymocytes, there is a point where they express both CD4 and CD8
True
Once the T lymphocytes reach the thymus, what proteins are they expressing?
the TCR, CD3 and either CD4 or CD8 proteins
What are Hassall’s corpuscles?
Graves of dead thymocytes
What cells are the “teachers” of thymocytes? How do they do this (3)?
Cortical epithelial cells, which provide:
- Cell-to-cell contact
- Cytokines
- Peptide hormones
What ensures that lymph only moves in one direction?
One-way valves on lymph vessels
What tissues are the main immunologic responders?
Lymph nodes
The thoracic duct empties its contents into what?
Left subclavian
What vessles bring in lymph to lymph nodes? Away?
Afferent = bring in Efferent = take out
The cortex of lymph nodes has what type of cells? Paracortex? Medulla?
Medulla and cortex = B cells
Paracortex = T cells