Studied by 3 people
immune system
A system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response; Provides resistance to disease
Two intrinsic systems of the immune system
Innate (nonspecific) defense system (first and second lines of defense)
Adaptive (specific) defense system (third line of defense)
Innate (nonspecific) defense system
constitutes first and second lines of defense; First line of defense: external body membranes (skin and mucosae); Second line of defense: antimicrobial proteins, phagocytes, and other \n cells (inhibit spread of invaders; inflammation most important mechanism)
Adaptive (specific) defense system
Third line of defense attacks particular foreign substances (takes longer to react than innate)
First line of defense
external body membranes (skin and mucosae); Innate/nonspecific
Second line of defense
antimicrobial proteins, phagocytes, and other cells (inhibit spread of invaders; inflammation most important mechanism); Innate/nonspecific
Third line of defense
attacks particular foreign substances (takes longer to react than innate); Adaptive/specific
pathogens
disease causing agents (microorganisms
Surface barriers
-Skin, mucous membranes, and their secretions \n -Physical barrier to most microorganisms \n -Keratin is resistant to weak acids and bases, bacterial enzymes, and \n toxins \n -Mucosae provide similar mechanical barriers
Pattern Recognition Receptors (PRRs)
proteins on or in cells that recognize specific compounds unique to microbes or tissue damage, allowing the cells to sense the presence of invading microbes or damage
Phagocytes
A type of white blood cell that ingests invading microbes (phagocytosis)
Neutrophils
most abundant phagocytes, but die fighting; become phagocytic on \n exposure to infectious material
Macrophages
develop from monocytes and are chief phagocytic cells; most robust phagocytic cell
Natural Killer (NK) Cells
-Nonphagocytic, large granular lymphocytes that police blood and lymph \n -Can kill cancer and virus-infected cells before adaptive immune system is activated \n -Attack cells that lack "self" cell-surface receptors \n -Kill by inducing apoptosis in cancer cells and virus-infected cells \n -Secrete potent chemicals that enhance inflammatory response
Inflammation
a localized response to an injury or to the destruction of tissues; triggered whenever body tissues are injured
Cardinal signs of inflammation
redness, swelling, heat, pain, sometimes loss of function
benefits of inflammation
-Prevents spread of damaging agents \n -Disposes of cell debris and pathogens \n -Alerts adaptive immune system \n -Sets the stage for repair
stages of inflammation
Inflammatory chemical release
Vasodilation and increased vascular permeability
Phagocyte mobilization
histamine
Chemical stored in mast cells that triggers dilation and increased permeability of capillaries; key inflammatory chemical
kinins, prostaglandins, cytokines and complement
Inflammatory mediators; cause vasodilation of local arterioles, makes capillaries leaky; many attract phagocytes to area
Phagocyte mobilization
-Neutrophils flood area first; macrophages follow \n -If inflammation is due to pathogens, complement is activated; adaptive immunity elements arrive
Pus
creamy yellow mixture of dead neutrophils, tissue/cells, and living/dead pathogens
Abscess
Collection of pus underneath the skin bc collagen fibers are laid down; may need to be surgically drained
