Histology: Lymphoid Organs Flashcards
What are the primary lymphoid organs?
- Bone Marrow
- Thymus
What are the secondary lymphoid organs?
- Lymph Nodes
- Spleen
- Mucosal Associated Lymphoid Tissue
What are the components of the thymus?
Cortex
Medulla
What cells predominate in the cortex?
T- cells with fewer epithelial cells
What are Hassall’s Corpuscles?
Concentric structure - thought to be degenerated epithelial cells
How does the thymus change in the adult?
Most of the thymus becomes replace with adipose tissue
What are the 3 parts of the lymph node?
Capsule
Cortex
Medulla
What is the space right below the capsule?
Subcapular Sinus
What are germinal centers?
Sites of B cell proliferation - follicle with germinal center is referred to as a secondary follicle
What is the periarteriolar lymph sheath?
They are a portion of the white pulp of the spleen. They are populated largely by T cells and surround central arteries within the spleen; the PALS T-cells are presented with blood borne antigens via myeloid dendritic cells.
What are the components of the red pulp?
- Open sinuses
- Cellular cords
What is MALT and where are they found?
It is a diffuse system of small concentrations of lymphoid tissue found in various sites of the body, such as the gastrointestinal tract, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages.
