Flashcards in Lecture 10 Deck (45):
Innate immunity refers to..
defences that are present at birth
Innate immunity are non specific defences acting against...
most microbes in the same way
Innate immunity has no memory component so it cannot
recall previous contact w/ foreign microbe
Innate immune system is always present as it..
-responds rapidly to an infection
-active before an infection
Innate immune system includes..
Types of leukocytes
large granules in their cytoplasm and are under light microscope
3 sub groups of granulocytes
weak phagocytes, they secrete chemo-attractants and release histamine which causes allergies and inflammation
destroy large pathogens which as pathogenic worms, produce extracellular digestive enzymes to attack parasite
strong phagocytes, leave the blood and enter infected tissue, destroy foreign microbes and particles by phagocytosis
have granules in their cytoplasm which are visible under high microscope
3 types of agranulocytes
initially not phagocytic, are immature. they leave the blood, enter into tissue and become macrophages
mature monocytes and strong phagocytes, often found in organs and filter out invading pathogens as blood passes through
present foreign material to cells of the adaptive immune system, antigen presentation
3 types of lymphocytes
-natural killer cells (NK cells)
Natural killer cells
responsible for killing infected body cells and tutor cells, they attack any body cell that displays unusual proteins in the plasma membrane
B and T lymphocytes
part of adaptive immunity
during infection monocytes and granulocytes migrate to the infected area
4 main phases of phagocytosis
phagocytes are attracted to foreign particles, damaged cells etc
phagocyte attaches to a foreign particle
pseudopods extend and engulf the particle, the particle is trapped in the phagosome
digestive enzymes enter the phagosome, takes 10-30 min to kill bacterium
Inflammation signs and symptoms
-loss of function
Inflammation functions to..
destroy an injurious agent and prevent the spreading of an injurious agent, it repairs and replaces damaged tissue
Stages of inflammation
blood vessels dilate more blood reaches affected area, this allows white blood cells to access the area, brings nutrients for fast healing
reddening, swelling (edema), increased temp and pain (due to tissue damage)
fibrinogen to clot formation, this segregates the affected area and prevents spread of infection
phagocytes destroy invading microbes
increase in body temp, controlled by hypothalamus
Fever is triggered by..
toxins, LPS, and chemical produced by the immune system (reset the bodies thermostat)
Fever results in..
-increased temp (faster metabolism, promotes healing)
-slows growth of heat limited microbes
-up to a certain temp, fever is defence against disease
composed of 30 proteins that circulate in the blood, work together as a cascade (the action of one protein triggers the action of the next)
Complement can be triggered by..
surface molecules of invading microbes
Result of complement cascade
C proteins attach to microbes and act as a flag to attract phagocyte, this increases phagocytosis by 1000x.
increases blood vessel permeability, attracts phagocytes to the infection site
formation of the membrane attack complex (MAC), pokes holes in the bacterial cell membrane
produced upon infection with a virus, interferes with viral replication, can be toxic to organs, released by infected cells to warn neighbouring cells. doesn't help cells already infected w/ virus
IFN allows neighbouring cells..
time to produce anti-viral proteins
IFN is effective only..
for short periods of time