Immune System Flashcards
What are the two divisions of the Adaptive immune system?
1) Humoral
2) Cellular
What type of cells make up the Humoral Immune system?
-B Lymphocytes
What is the main job of B Lymphocytes?
-Create plasma cells to secrete antibodies
What differentiates into plasma cells?
B Lymphocytes
What stimulates B Lymphocytes?
Interleukins
What antibodies do B lymphocytes have on their surface?
- IgM
- IgD
What is an antigen?
a non-self substance
What portions of antibodies are different between different types of Abs?
- Antigen Binding site
- Fc region (Heavy Chain)
What do IgM antibodies do?
- Activate Complement
- Activaet B cells
What is complement?
A cascade of proenzymes/proteases involved in mediating the immune response
What do IgG antibodies do?
Activate Macrophages and neutrophils
-Can also activate complement
What do IgA antibodies do?
- Agglutinates antigen
- Activates effector cells
What do IgE antibodies do?
- Bind to mast cells and basophils
- Stimulate release of histamine, heparin, and cytokines
What do IgD antibodies do?
Activate the B lymphocyte (receptor)
What do T-Lymphocytes do?
Mediate cellular immunity
What stimulates T-Lymphocytes?
Major Histocompatability Complex (MCH’s)
What do Cytotoxic T Lymphocytes (CD8+) do?
Induce programmed cell death or lysis
What MHC class do Cytotoxic T Lymphocytes recognize?
MHC-I
What do Helper T Lymphocytes (CD4+) do?
Secrete cytokines to stimulate other immune cells
What MHC class do Helper T Lymphocytes Recognize?
MHC-II
What do Regulatory T Cells do?
-They are capable of suppressing immune response
What do Natural Killer Cells do?
Kill viral infected cells and tumor cells in a nonspecific (innate) manner
-Don’t use MHC presentation
What do Macrophages and Neutrophils do?
Phagocytose material coated with IgG and IgM antibodies
What do mast cells and basophils do?
- Release Histamine and Heparin
- Also release chemotactic agents
What constitutes the Lymphoid tissues?
- Thymus
- Bone Marrow
- Lymph Nodes
- Spleen
What occurs in the cortex of the thymus?
-T lymphocytes Proliferate and program in cortex (positive selection process for MHC
What happens to T lymphocytes that do not bind an MHC?
The die via apoptosis
What happens to T lymphocytes that DO bind an MHC?
- migrate to medulla of Thymus where they are negatively selected for recognition of self antigens
- Dendritic cells present self antigens
What does a Hassall’s Corpuscle do?
Makes interleukins and cytokines
Where are Hassall’s Corpuscles located?
Medulla of the Thymus
What part of the IgE antibody stimulates the release of histamine, heparin, and cytokines?
The Fc Region
What are the 5 layers that form the blood-thymic barrier?
- Endothelial cell (Tight)
- Basal Lamina (Tight)
- Some connective tissue
- Basal Lamina of Reticular Cell (Tight)
- Thymic epithelial cell (Tight)
Do thymic epithelial cells make fibers?
no, they are a type of epithelial cell
What do lymph nodes do?
Filter regional lymph fluid
What type of collagen do reticular cells of the lymph node make?
Collagen Type III
What is happening in Lymphoid (B cell) nodules in lymph nodes?
B cell Proliferation
What does the HEV do?
Point of entry for lymphocytes into the lymph node
Where are HEVs located?
The paracortex region of the lymph node
Which lymphatic tissues have reticular cells that make fibers?
Lymph node and Spleen
What is the primary purpose of the spleen?
a blood filter
What makes up the white pulp of the spleen?
- lymphoid nodules
- periarteriolar lymphoid sheaths (PALS)
What makes up red pulp of the spleen?
- sinusoids rich in blood
- splenic cords of Billroth
Where are MALT tissues found?
Digestive, Respiratory, and Genitourinary Tracts
What is MALT?
- Mucosa-Associated-lymphoid-Tissue
- Tonsils
What is the purpose of tonsils?
Survey substances brought into the mouth, throat, pharynx
What is contained within medullary cords of the lymph node?
T and B lymphocytes-Many Plasma cells
What is contained within medullary sinuses of the lymph node?
meshwork of processes from reticular cells-Many macrophages and neutrophils if draining an infected region
What do the splenic trabeculae do?
Carry branches of the splenic artery, vein, lymphatics, and nerves into the splenic pulp
What happens in the red pulp of the spleen?
Effete RBC’s are removed
What is contained within the splenic cords of Billroth?
A network of reticular cells and fibers filled with T and B lymphocytes, macrophages, other leukocytes, and RBCs
What are Stave Cells?
cells that make up the splenic sinusoids, resembling a loosely organized wooden barrel
