body defences and innate immunity Flashcards
immunity
specific resistance to disease
immune system
is a functional system rather than an organ system
innate (nonspecific) immunity- first line of defence
-skin
-mucous membranes
-secretions of skin and mucous membranes
innate (nonspecific) immunity- second line of defence
-phagocytic cells
-natural killer cells
-antimicrobial proteins
-inflammatory response
-fever
adaptive (specific) immunity
-lymphocytes
-antibodies
-macrophages and other antigen-presenting cells
what is the second line of defence?
-cells and chemicals
systemic response is triggered by?
-triggered by pyrogens
-inhibits multiplication of bacteria
what regulates the body, and at what temperature?
-the hypothalamus regulates body temperature at 37
how can the body temperature reset?
-the hypothalamus thermostat can be reset higher by pyrogens
-these are secreted by white blood cells
what do high temperatures inhibit?
-the release of iron and zinc from the liver and spleen
what can hemocytoblast stem cells develop into?
-myeloid stem cells
-lymphoid stem cells
what can myeloid stem cells develop into?
-basophils
-eosinophils
-neutrophils
-monocytes
-platelets
-erythrocytes
what can lymphoid stem cells develop into?
-lymphocytes
what are myeloid used for?
-they play a role in the innate immune system
what are lymphocytes used for?
-they play a role in the adaptive immune system
what is phagocytosis?
-when cells engulf foreign materials
step 1 of phagocytosis
-phagocyte adheres to pathogens
step 2 of phagocytosis
-phagocyte engulfs the particles, forming a phagosome
step 3 of phagocytosis
-lysosome fuses with phagocytic vesicle, forming a phagolysosome
step 4 of phagocytosis
-lysosomal enzymes digest the pathogens or debris, leaving a residual body
step 5 of phagocytosis
-exocytosis of the vesicle removes indigestible and residual material
phagocyte mobilization during inflammation
-neutrophils
-natural killer cells
-antimicrobial proteins
neutrophils- step 1
-neutrophils migrate to the area of inflammation by rolling along the vessel wall
neutrophils- step 2
-neutrophils squeeze through the capillary walls by diapedesis to sites of inflammation
neutrophils- step 3
neutrophils gather in the precise site of tissue injury (positive chemotaxis) and consume any foreign material present
natural killer cells
-first lymphocytes to react to infection
-roam the body in blood and lymph
what do natural killer cells do?
-lyse (burst) and kill cancer cells, virus-infected cells, and some other non-specific targets
-release chemicals called perforin and granzymes to degrade target cell contents
-release powerful inflammatory chemicals
antimicrobial proteins
-group of antimicrobial proteins found in plasma
-enhances phagocytosis by opsonization
-intensifies inflammatory response
-hinders reproduction of microorganisms
antimicrobial proteins
- interferons
- iron-binding proteins
interferons
-small proteins secreted by virus-infected cells
-bind to membrane receptors on healthy cells surfaces to interfere with the ability of viruses to multiply
-do not help fight bacterial or fungal infections
iron-binding proteins
-reduce iron available to bacteria, inhibits their ability to reproduce
-ferritin- found in the liver, spleen and red bone marrow
-haemoglobin
-myoglobin- found in muscle tissue
