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what are granulocytes?
- visible cytoplasmic graules that stain with Wright's stain
- lobed nulei
- all phagocytic to some degree
- neutrophils, eosinophils, basophils
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what are agranulocytes?
- lack visible cytoplasmic granules
- have spherical or kidney shaped nuclei
- lymphocytes, monocytes
- lymphocytes repond to specific individual pathogens
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what are two categories of leukocytes?
agranulocytes and granulocytes
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decreasing abundance in blood of granulocytes and agranulocytes
never let monkeys eat bananas
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Describe neutophil
- pale red nd blue
- dense, contorted multilobular nucleus
- first WBC to arrive at injry
- granules contain hydrolytic enzymes
- phagocytic, attacking and digesting bacteria
- numbers increase during acute bacterial infections
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eosinophil
- red cytoplasmic granules
- two obed nucleus
- phagocytic, also exocytotic
- allergies and asthma
- modulates immune response
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basophil
- purplish black
- rarest WBC
- smaller than neutophils and eosinophil
- contain histamine (acts as vasodilator to attract WBC to inflamed sites)
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monocytes
- largest WBC with large, kidney bean shpaed nucleus
- pale blue
- migrate into tissues and become macrophages
- aggressive phagocytes-crucial against viruses, parasites and infections
- activate lymphocytes to mount an immune response
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lymphocyte
- slightly larger than RBC; nucleus taking up most of cell
- large numbers are migrating in and out of tissues and lymphoid tissue
- few circulates in blood
- some attack foreign cells, others secrete antibodies into circulation
- two types: T cells and B cells
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what are the phases to halt bleeding and prevent blood loss?
vascular, platelet, and coagulation
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vascular phase
- vascular spasm: vasoconstriction of damaged blood vessel (blood vessels contain smooth muscle lined with endothlium)
- endothelial cells beocme sticky
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what is vascular phase triggered by?
- direct injury to vascular smooth muscle
- chemicals released by endothelial cells and platelets
- pain reflexes
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the platelet phase
- platelets attach to sticky endothelium and exposed collagen fibers
- platelets release chemical messngers
- more platelets arrive and stick to each other forming a platelet plug (pos. feedback)
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coagulation phase
- fibrinogen converts to fibrin
- fibrin mesh grows, trapping cells and more platelets forming a blood clot
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what does the extrinsic and intrinsic paths begin with in the clotting factors
extrinsic path begins with damaged tissue releasing tissue factor; intrinsic path begins with activation of proenzymes exposed to collagen fibers
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how does blood clotting begin?
- when either extrinsic or intrinsic pathways activate Factor X
- forms enzyme prothrombinase, which converts prothrombin into thrombin
- thrombin converts fibrinogen into fibrin and stimulates tissue factor and platelet facts
- positive feedback loop prevents blood loss
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what is factor XIII
thrombin with Ca activates this fibrin stabilizing factor which cross links fibrin and strengthens/stabilizes clot
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what is the importnace of clot retraction?
- after fibrin traps platelets and RBC, platelets contract to pull tissue close together (actin and myosin contract)
- contraction pulls on fibrin strands and squeezes serum from clot and draws ruptured blood vessel edges
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platelet derived growth factor (PDGF)
stimulates division of smooth muscle cells and fibroblasts to rebuild blood vessel wall
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vascular enothelial growth factor (VEGF)
stimulates endothelial cells to multiply and restore endothelial lining
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what are the coverings of the heart
- surrounded by pericardial cavity (air space); lined by serous membrane, the pericardium
- -visceral pericardium or epicardium covers the heart (inner wall)
- -parietal pericardium (outer wall) lines inner surface of pericardial sac
- perdiadial fluid found between layers, reduces friction
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what are the three layers of the heart wall?
- epicardium outer surface
- myocardium: prodces twisting and squeezing during contraction
- endocardium: covers inside chambers and heart valves
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cardiac muscle contraction
- depolarization: due to Na influx through fast channels. pos feedback opens many Na channels, reversing the membrane potential. channel inactivation ends this phase
- plateau phase: due to Ca influx through slow Ca channels, keeps the cell depolarized due to few K channels open
- repolarization: Ca channels inactivating and K channels opening. This allow K efflux
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