Immunology Flashcards
First line of defense
Mechanical barriers such as the skin and mucous membranes.
All other non-specific defenses are part of the second line of defense.
Second line of defense: Chemical barriers
- Enzymes in body fluids such as pepsin in the stomach and lysozyme found in tears that ruptures bacterial cell walls.
- Inferferons block viral replication
- Defensins are produced by neutrophils that make holes in bacterial cell walls.
- Collectins are proteins that protect against my bacteria, yeast, and virus. Precursor to complement.
- Complement is a group of proteins in plasma that stimulates inflammation.
Interferons and complement both
Play a roll in stimulating or attracting phagocytes for phagocytosis.
Are NK cells innate or active immunity?
Innate. They defend against viruses and cancer cells by secreting performs that lyse cell membranes.
Perforins
Secreted by NK to lyse cell membranes of cells with cancer or viruses inside.
The 4 signs of inflammation
Rubor- redness
Dolor- pain
Calor- Heat
Tumor- Swelling
Sepsis
When infection spreads to other parts of the body
Major 6 actions of an inflammation response
- Blood vessels dilate, causing tissues to show 4 signs of inflammation.
- White blood cells invade. Neutrophils.
- Clotting factors seep into the area, forming clot of fibrin,
- Fibroblasts arrive to form a CT sac around the injured tissues.
- Phagocytes are active and remove bacteria/dead cells.
- Cells divide to replace old injured cells.
The most active phagocytic cells are
Neutrophils and monocytes (macrophages and dendritic cells)
Chemotaxis
Chemicals from damaged tissue attract phagocytic cells to site of injury.
Monocytes that leave the blood become
Macrophages- can either be free or fixed in tissues.
What stimulates a fever
Interleukin-1 (IL-1). Stimulated when infection stimulates lymphocytes to proliferate.
How many T, B, and NK cells in the blood
70-80% are T cells
20-30% are B cells
1% are NK cells
T cell origin
Created in the bone marrow and mature in the thymus. Most go on to roam in the blood, but some settle in lymph nodes, thoracic duct, and white pulp of spleen.
B cell origin
Created in the bone marrow and mature in the bone marrow. Go to the blood, lymphatic organs, and intestinal linings and tonsils.
T helper cells interacts with cytotoxic T cell that has been combined with an identical antigen by
Interleukin-2. This activates cytotoxic T cells to proliferate into memory T cells and more cytotoxic T cells.
T helper cell interacts with B cell that has been combined with an identical antigen by
Cytokines. This activates the B cell so it is able to proliferate into plasma (effector) cells and memory cells.
4 types of cytokines
CSF- stimulates bone marrow to produce more lymphocytes.
Interferons- Block viral replication and attack viral cells/cancer cells.
Interleukins- Control lymphocyte differentiation and proliferation. Also can cause fever. Controlled by T cells.
TNF- Stops tumor growth and releases growth factors
Once B cells bind to their Ag, what happens?
They have to wait for approval by T helper cells. T helper cells also activated will release cytokines that allow the B cell to proliferate into plasma (effector) and memory cells.