Organs in the immune system Flashcards
What are the primary lymphoid organs
The bone marrow and thymus
What do the primary lymphoid organs provide for lymphocyte maturation
growth factors and self-antigens for the selection of self-antigens for maturing lymphocytes
Where do B lymphocytes mature
in the bone marrow, then migrate to spleen
Where to D lymphocytes mature
in the thymus
What are the secondary lymphoid organs
Lymph nodes, spleen, mucosal immune system
Where do lymphocytes see self-antigens
in the primary lymphoid organs where they have self-tolerance
Where do lymphocytes encounter foreign antigens
Secondary lymphoid organs
Where do the lymphocytes go after bone marrow?
Mature in primary lymphoid organs (B cells in bone marrow, T cells in thymus), then circulate to secondary lymphoid organs
What happens if a naieve lymphocyte encounters a foreign antigen?
they may respond in the secondary lymphoid tissues, or return by lymphatic drainage to blood/other secondary lymphoid organs
Where are naieve lymphocytes activated by antigens
Secondary lymphoid organs
What are the B lymphocyte effector cells
antibody-secreting plasma cells
What do CD4 cells turn into
T helper cells, cytokine-producing
What do CD8 cells turn into
Cytotoxic T lymphocytes
Where do effector T cells go from secondary lympoid organs
migrate to infected tissues
What does the lymphatic system consist of
Vessels called lymphatics that drain fluid from tissues for immune responses
What do lymphatic capillaries absorb
interstitial fluid formed in tissues (accumulates during infection)
What is the fluid in the lymphatic drainage system
Lymph
How much lymph is circulating in the system
2 liters
What are in lymph nodes
naive b and t cells that get to respond to antigens collected by the lymph from tissues
Where are b and t cells in lymph nodes
B cells are in follicles
T cells are in paracortex
What does segregation of B and T cells in the lymph node ensure
Each cell encounters the correct signals and antigens for an effective immune response
What is the main function of the spleen
remove damaged blood cells and opsonized microbes, initiate adaptive immune responses to blood antigens
What do red pulp macrophages do
filter for blood, removing microbes, damaged cells, and opsonized cells
What does white pulp contain
densely packed lymphocytes with zones for T and B cells
What is the cite of antigen presentation for B and T cells
the marginal zone in the spleen between red pulp and white pulp
What is a tell sign on a blood smear that a patient has a dysfunctioning (or lacks) a spleen
Red blood cells with nuclei in them (the spleen removes these nuclei)
Describe the innate response at a site of injury
1.Microbes enter the skin through a break in the skin
2. Sentinel cells (macrophages and dendritic cells) are activated and secrete inflammatory mediators
3. Activation of complement system and microbes tagged for destruction
4. Neutrophils are recruited to site of infection and phagocytose microbes
Describe the adaptive response sequence
- Dendritic cells take pathogen from injury and bring to lymph nodes
- Dendritic cells display peptides to naive T cells
- T cells proliferate and differentiate into effector T cells
- CD4 cells activate B cell
- CD8 t cells travel to site of infection and kill infected cells
- Helper T cells activate b cells and APCs
- B cells produce IgM memory antibodies
What are effector cells
Actively involved in killing a cell (T cells (helper and CT, becuase they both are involved), and macrophages, neutrophils
