1 dr. abbas foroutan cardiac mechanics heart physiology heart as a pump 1384-85oct.2005 by: dr....
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1D
r. abbas Foroutan
Cardiac M
echanics
Heart PhysiologyHeart PhysiologyHeart as a pumpHeart as a pump
1384-851384-85Oct.2005Oct.2005
By: Dr. Abbas ForoutanBy: Dr. Abbas ForoutanShaheed Beheshti Univ. Med. Sci.Shaheed Beheshti Univ. Med. Sci.
20D
r. abbas Foroutan
Cardiac M
echanics
Cardiac OutputCardiac Output
CO = SV * HRCO = SV * HRPreloadPreloadContractilityContractilityAfterloadAfterloadHRHR
21D
r. abbas Foroutan
Cardiac M
echanics
Part 3Part 3
PreloadPreload Frank –StarlingFrank –Starling
LawLaw
22D
r. abbas Foroutan
Cardiac M
echanics
No spatial summationNo spatial summation No Time domain summation (no No Time domain summation (no
tetanus)tetanus)
76D
r. abbas Foroutan
Cardiac M
echanics
CARDIOVASCULAR CHANGES CARDIOVASCULAR CHANGES DURINGDURING
EXERCISE EXERCISE Cardiac outputCardiac output
heart rate heart rate ( ( sympathetic adrenergic and sympathetic adrenergic and parasympathetic parasympathetic activity)activity)
stroke volume stroke volume ( ( CVP; inotropy; lusitropy) CVP; inotropy; lusitropy) Mean arterial pressureMean arterial pressure and and pulse pressurepulse pressure
CO increases more than SVR decreaseCO increases more than SVR decrease stroke volume increases pulse pressurestroke volume increases pulse pressure
Central venous pressureCentral venous pressure Venous constriction Venous constriction ( ( sympathetic adrenergic activity) sympathetic adrenergic activity) Muscle pump activityMuscle pump activity Abdominothoracic pumpAbdominothoracic pump
Systemic vascular resistanceSystemic vascular resistance Metabolic vasodilation in active muscle and heartMetabolic vasodilation in active muscle and heart Cutaneous vasodilation Cutaneous vasodilation (( sympathetic adrenergic activity) sympathetic adrenergic activity) Vasoconstriction in splanchnic, nonactive muscle, and renal Vasoconstriction in splanchnic, nonactive muscle, and renal
circulationcirculation ( ( sympathetic adrenergic activity) sympathetic adrenergic activity)CVP, central venous pressure; CO, cardiac output; SVR, systemic vascular resistanceCVP, central venous pressure; CO, cardiac output; SVR, systemic vascular resistance
83D
r. abbas Foroutan
Cardiac M
echanics
Return of blood to the heart through veins from the extremities occurs by low ∆P, but also, as in lymphatics, by one-way valves, "milking action" of skeletal muscles, and — within the torso — by lowered thoracic pressure each time the diaphragm is lowered (no valves within torso).
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