unit 9 Flashcards
Innate body defenses (first line of defenses)
Non aggresive-
Intact skin
mucous membrnaes
Normal flora
GI tract
Blood brain barrier
Oyxgen tensions
Iron levels
Defecation/vomitting
Fever
aggressive-
Lysozyme
Sebum
Cydal agents
Intact skin
physical/chemical barrier
Mucous membranes
hair
saliva
ciliated cells
tears
mucous
Normal flora
Barrier/bacteriocin production
GI tract
Stomach (low pH)
Digestive juice /biles
Blood brain barrier
ependymal cells/ astrocytes
microglial cells (phagocytes) in the region
Oxygen tensions
aerobic (lungs
anaerobic (intestines)
Iron levels (microbes requiring iron)
- during infection -> hypoferremia decreases low iron levels
-hypoferremia/low iron levels inhibits growth
Defecation / vomitting (ridding microbes)
body defense mechanism
Fever
release of pyrogens
Benefits of low grade fever
-increase immune mechanism
-increase in phagocytes
-increase in interferons
- inhibits growth of certain microbes
Lysozyme
- gram + bacteria manly
-capsules resist it
-found in tears, saliva, perspiration, granules of neutrophils
Sebum
-fatty acids toxic to gram -‘s
-protective film around skin
Complements (cydal agents)
-complement: gram -‘s / viruses
- serum protein
- exists in inactive state
- once activated, attaches to microbe / kills it
What activates complements?
presence of fever
viral infection
presence of bacterial antigen
Interferon (cydal agents)
-anti viral protein
- all cells produce small amounts of interferons
- protects uninfected cells from being infected by virus
- given in large doses for various therapeutic reasons (HIV/HIB)
Leukins (cydal agent)
produced by wbc’s (leukocytes)
Plakins (cydal agent)
platlets
Lactoferrin (cydal agent)
breast milk, tears, neurophils
Transferrin (cydal agent)
serum protein
regulates absorption , transportation , metabolism of iron
2nd line of defense
phagocytosis (phagocytic defenses)
what is phagocytosis?
cells capable of ingesting microbes/ debris / foreign matter
What cells are phagocytic?
WBC’s and their derivatives
5 steps of phagocytosis
1- chemotaxis
2-adherance = opsonization (opsonin proteins
3-ingestion
4- digestion
5- release or discharge
What is the purpose of opsonnin protein?
allows phagocytic cell to bind to cell
M. leprae and M.Tubercolosis are not effected by what?
phagocytosis
Types of phagocytic cells (wandering or free phagocytes)
Granulocytes ( neutrophils , Eosinophils , Basophils)
Agranulocytes ( monocytes , lymphocytes)
Neutrophils
- 60 -> 70% of total WBC
- very phagocytic
- scavenger cells
-Granules = lysozyme /lactoferrin
-Leukocytosis = acute infections/ neutrophilia
Eosinophils
- 2 -> 4% of total wbc
- some phagotcytic activity
- role in allergies
- granules = histamines
- eosinophilia = allergies / parasistic infections
Histamine purpose
widens blood vessels
Basophils
- 0.5 -> 1% WBC’s
- some phagocytic activity
- important role in graft rejection / viral immunity
- granules = heparin , serotonin , histamine
- least abundant phagocytic cell
Monocytes
- 3 -> 8 % of wbc
- not phagocytic in blood
- macrophage when -> tissue
- Monocytosis = certain bacterial infections (TB , Rickettsial infections) , protoza and fungal infections
-no granules
Fixed phagocytes or Histiocytes
alveolar macrophages (lungs)
kupffer cells (liver)
lymphocytic macrophages (lymph nodes)
microglial cells (brain / CNS)
osteoclasts (bones)
what is inflammatory response
sum of reactions in the body incited by injury
Vasodilation
- increase in diameter of blood vessels
- increase vascular pearmability
-inc blood flow from capillaries -> damage tissue,
edemea
Types of vasodilation
- histamines
- bradykin
-kinin
Hemostatic plug
fibrin clot (wall-off)
Pus formation
dead cells/ body fluids
Chemotaxis
phagocytes move -> injured area
Margination
wbc cling to lining of blood vessels
Diapedesis
phagocytes move from blood -> tissue
fever starts the process
takes only 2 minutes
Neutrophil duration
- lots arrive within hrs
Monocyte
- arrive in 12 hrs
- enters tissue/ become macrophages
Eosinophils / basophils appear
- provides vasodilators
Tissue repair
Fibrinolysis / Fibrinoblasts
Fibrinolysis
plasminogen -> plasmin which breaks down fibrin clot
Fibroblasts
formation of scar tissue