Ch 15: The Immune System (Inflammation and IN

innate immunity

first line of defense

immediate response

not specific

present before birth

always “on” (from time of infection, thru incubation period, and until infection ends)

adaptive immunity

specific to its target

slower to activate

must “see” the antigen

generates memory cells

hematopoietic precursor cell (bone marrow)

all blood cells originate from

t cell and b cell

types of lymphocytes

eosinophil, basophil, neutrophil

also called granulocytes

type of polymorphonuclear leukocytes (PMNs)

neutrophil

most abundant white blood cell in the blood

acts like first responder

can engulf microbes via phagocytosis

basophil and eosinophil

releases granules with toxic substances when encountering pathogen

also releases vasoactive chemical mediator (important for inflammation)

mast cell

has granules with histamine/heparin and doesn’t circulate in bloodstream

stays in connective tissue and mucosa

neutrophil

which white blood cell dominates during the initial phase of a bacterial infection?

monocyte

circulates in the blood

differentiates into macrophages and dendritic cells

macrophage

type of monocyte but does NOT circulate in the blood

widely distributed throughout the body

“presents” antigens on cell surface of T cells

when monocytes circulate in the blood and enter tissue they develop into the macrophage

once they become a macrophage, they don’t circulate

process of monocyte to macrophage

1) bacterium binds to phagocytic cell surface

2) phagocyte pseudopods extend and engulf the organism

3) phagosome is formed

4) lysosome fuses and deposits toxic substances/enzymes into phagosome

5) contact with pathogen causes destruction

phagocytosis steps