E1 Ch 5 Inflammation Flashcards
body defenses
first line of defense
- nonspecific
- mechanical barriers such as intact skin and mucous membranes block entry of bacteria and harmful substances into the tissues
- body secretions such as saliva or tears contain enzymes or chemicals that inactivate or destroy potentially damaging material
second line of defense
- nonspecific
- phagocytosis (neutrophils and macrophages randomly engulf and destroy bacteria, cell debris, or foreign matter)
- inflammation (sequence of events intended to limit the effects of an injury or a dangerous agent in the body)
- interferons (nonspecific agents that protect uninfected cells against viruses)
third line of defense
- specific
- antibody/lymphocyte production provides protection by stimulating the production of unique antibodies or sensitized lymphocytes following exposure to specific substances
normal capillary exchange
- not all capillaries are open in a particular capillary bed unless the cell’s metabolic needs are not being met
- movement of fluid, electrolytes, oxygen, and nutrients out of the capillary at the arteriolar end is based on the net hydrostatic pressure
- at the venous end of the capillary, osmotic pressure facilitates the movement of fluid, carbon dioxide, and other wastes into the blood
physiology of inflammation
- inflammation is the body’s response to a tissue injury
- results in redness, swelling, warmth, pain, and sometimes loss of function
- disorders are named using the ending -itis
- normal defense mechanism in the body
- intended to localize and remove an injurious agent
- not the same as infection (infection has microbes present)
causes of inflammation
- direct physical damage (cuts or sprains)
- casuistic chemicals (acids or alkali)
- ischemia
- infarction
- allergic reactions
- extreme heat or cold
- foreign bodies (splinters or glass)
- infection
steps of inflammation
- bradykinin is released from injured cells
- bradykinin activates pain receptors
- sensation of pain stimulates mast cells and basophils to release histamine
- bradykinin and histamine cause capillary dilation
- this results in an increase of blood flow and increased capillary permeability
- break in skin allows bacteria to enter the tissue
- this results in the migration of neutrophils and monocytes to the site of injury
- neutrophils phagocytize bacteria
- macrophages leave the bloodstream and phagocytose microbes
acute inflammation
rapid onset; severity of the inflammation varies with the specific cause and duration of exposure; chemical mediators affect blood vessels and nerves in the damaged area causing:
- vasodilation
- hyperemia
- increase in capillary permeability
- chemotaxis to attract cells of the immune system
chronic inflammation
may develop following an acute episode of inflammation; less swelling and exudate; more lymphocytes, macrophages, and fibroblasts; more tissue; more collagen is produced, causing more fibrous scar tissue forming
histamine
immediate vasodilation and increased capillary permeability
chemotactic factors
for example, attract neutrophils to site
platelet activating factor
activate neutrophils, platelet aggregation
cytokines (interleukins, lymphokines)
increase plasma proteins and erythrocyte sedimentation rate, induce fever, chemotaxis, leukocytosis
leukotrienes
later response; vasodilation and increased capillary permeability, chemotaxis, leukocytosis
prostaglandins
vasodilation, increased capillary permeability, pain, fever, potentiate histamine effect
kinins (ex. bradykinin)
vasodilation and increased capillary permeability, pain, chemotaxis
complement system
vasodilation and increased capillary permeability, chemotaxis, increased histamine release