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32 Cards in this Set
- Front
- Back
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pressure gradient inversely propotional resistance
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different pressures at the 2 ends of the pipes
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Flow =
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Pressure / resistance = del P / R = P pi r^4 / 8 L visc
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Blood flow (ml/min)
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amt of blood moving thru an area OR amt of blood in the entire cardiovascular system in a given time
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cardiac output
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amt of blood heart pump in 1 minutes
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Blood flow regulation
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by diameter of blood vessels at different areas
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Factors affect resistant
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radius ------ length ---------- viscosity
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Radius
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vasoconstriction (plague) causes small radius (more frictional drag around the wall) --------- vs dilation
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length
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longer --- more resistant (more friction) --- gain weight or growing
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Viscosity
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determined by amt of hematocrit (RBC -- ratio 1/3 Hb / Hct) --- plasma proteins ------ platelets ----------- WBC
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Peripheral resistance
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r = 8Lvis / pi r^4
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Laminar flow
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free flowing blood affect greatly by radius (r^4)
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factor affect viscosity
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dehydration --- polycythemia --- anemua
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Form elements -------------- (are not plasma proteins)
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RBC - WBC - platelets
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larger arteries close to heart valve have more ______________
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elastic tissue in their tunics to accommodate these changes
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Normal heartbeat
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70 bpm
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Diastole vs Systole
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Dilate vs Contract
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EDV depends on ______________
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the filing time (End Diastolic Volume)
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Stroke volume
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the volume ejected per ventricular contraction -
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ESV
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the vol remaining in the ventricle after contraction (End Systolic Volume)
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CO (Cardiac Out = Blood Flow) vs BP
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CO = HR x SV and P = flow x R ==== HR x SV x R ==== HR x SV x 8Lvis / (pi r^4)
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SV =
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EDV - EDV (100-60=40)
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Factors affect SV
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preload ------- contractility and afterload
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Frank-Starling law
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more blood comes back from venous system --- heart stretches more ---- pump stronger
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Preload
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degree of stretching by the EDV ----------- amt of ventricular filling b/t strokes (EDV magnitude) -------------- inc by SLOW HR ---- more time to fill ----------- OR exercising more venous blood return --> inc EDV ---- vs dehydration and blood loss
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Contractility
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refer to the cardiac muscle strength (ventricle) and ability to generate force ========
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Intrinsic mechanism
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sympathetic -- hormones --- contractility (inside the heart)
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Length tension
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more volume ------- stretch out more ---------- more force
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Afterload
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back Pressure of blood in the Aorta and pulmonary trunk on Aorta and Pulmonary valves
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Stroke volume increases by
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inc venous return (inc EDV) ------- sympathetic/ epi hormone (inc contract) ------------- DEC afterload (aterial pressure) ---> opposite wt HTN (too much afterload) reduce SV
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CO (mL/ min) and Total blood flow
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are proportional --- to keep P in a normal range if SV dec --- HR inc
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Aortic valve stenosis ...........
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partial blockage of aortic valce ---- inc resistant to blood flow and LV afterload -----> heart contract stronger --- build more muscle ---- (bad for valve stenosis - more muscle less vol) --- (good for athlete -- more volume pump stronger)
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Atherosclerosis --- plaque and lost elasticity
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incr resistant ---- decrease flow rate ------- lead to heart disease
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