Lymphoid System Flashcards
Where is the thymus located?
- chest cavity/thorax
- below thyroid gland
- overlying the heart
Where is the spleen located?
- upper-left quadrant of abdomen
- below diaphragm
where cells develop
primary lymphoid organs
Large lymphoid organ surrounded by connective tissues
spleen
Comprises immune cells located below the skin
cutaneous immune system
consist of diffusely distributed lymphoid cells and follicles that underlie all regions coated with mucosa
Mucosa-Associated Lymphoid Tissue
(MALT)
Small encapsulated structures located at the junction of the main lymphatic tracts
lymph nodes
Give the 4 secondary lymphoid organs
- spleen
- lymph nodes
- mucosa-associated lymphoid tissue (MALT)
- cutaneous immune system
Filters out worn-out RBCs, microorganisms, RBC antigens
red pulp
Lymphocytes spend about _____ in the blood before
they proceed to their specific secondary lymphoid organs
30 minutes
Special T-cells and APC located in the epidermis
cells of Langerhans
Give the 3 lymph nodes’ divisions
- cortex
- paracortex
- medulla
Give the spleen’s division with percentages
- red pulp (80%)
- white pulp (20%)
Contains antigen-presenting cells (APC)
(dendritic cells, macrophages)
white pulp
weighs 1300-1500 g
bone marrow
Main source of hematopoietic stem cells
bone marrow
Increases in size until it reaches peak development during adolescence and gradually atrophies
thymus
storage of cells
secondary lymphoid organs
largest tissue of the body
bone marrow
- cascade
- lymphocytes go to specific secondary lymphoid tissues
lymphocyte homing
Continuous flow of lymphocytes going to the blood and to the lymphatic system and back into the blood
lymphocyte recirculation
Lymphocytes have receptors that are specific to ligands found in the tissues
lymphocyte homing
Give the 2 primary lymphoid organs
- thymus
- bone marrow
