Immune system Ch 21 Flashcards
2 types of immunity
Innate
Adaptive
Innate immunity/non-specific
First line defense, skin and body membranes.
Second line: hallmark is inflammation and consists of antimicrobial proteins, phagocytes and other cells that inhibit invaders.
Involves lectins
Adaptive Immunity/specific
Third line of defense, consists of humoral and cellular immunity
Involves antibodies
Attack specific invaders and is slower to respomd
Protective materials in skin and mucous membranes
Acid mantel of the skin
Enzymes: found in saliva, respiratory mucus and eye.
Mucin: lines the digestive and respiratory tracts
Defensins: broad spectrum antimicrobial peptides secreted by the skin and mucus membranes
Other chemicals: in the skin sebum and eccrine sweat are toxic to bacteria.
Phagocytes
Neurophils: most abundant
Macrophages: most voracious and derive from monocytes
Opsonization
Any pathogen that is coated with complement proteins called opsonins. These are markers to identify them as an invader.
Natural Killer cells
Police the blood and immune system to find and lyse cancer and virus infected cells before the adaptive immune system is activated.
Inflammation response
Triggered when ever there is tissue damage
Prevents the spread of damaging agents to surrounding tissue
Disposes of cell debris and pathogens
Alerts adaptive immune system
Sets the stage for repair
Mast cells are a key component and release histamine
Phagocyte mobilization
Leukocytosis: Neurophils enter the blood from bone marrow
Margination: Neurophils cling to capillary wall
Diapedesis: They then flatten and squees out of the capillary
Chemotaxis: neutophils follow chemical trail.
Chemotaxis
Inflammatory chemicals act as homing devices and WBC migrate to the site of inflammation
Interferons
Small proteins that help protect cells that have not yet been infected. IFN’s diffuse to nearby cells from infected cells and interfer with viral replication of DNA and blocking protein synthesis
Complament System
The major mechanism of destroying foreign substances in the body. A group of 20 plasma proteins that normally circulate in the blood. When activated they lyse and kill invaders
Complements both active and innate immune systems
3 important factors of adaptive response
It is specific
It is systemic
it has memory
Humoral immunity
Antibody mediated immunity, provided by antibodies present in the bodies fluids.
Cellular Immunity
Cell-mediated immunity: when lymphocytes themselves rather than antibodies, defend the body.
Directly: by killing infected cells
Indirectly: by releasing chemicals that enhance the inflammatory response and activate other WBCs