HHP 3500 Lecture Notes - Lecture 25: Myocyte, Troponin, Afterload

• School: University of Iowa
• Department: Health and Human Physiology
• Course: HHP 3500
• Professor: Peterson Clayton

Document Summary

Cardiac output-measure of blood flood throughout body: stroke volume= 70 ml at rest, ejection fraction-% of blood ejected during systole - >50% at rest, cardiac output-volume of blood pumped by each ventricle per minute (l/mi) Determined by heart rate and stroke volume (co= hr x sv) Typical resting is 72 beats/min x 70 ml/beat = 5000 ml/min = 5 l/min. During max endurance exercise: 195 beats/min x (200- Controlled by hr- controls act in opposition (para slows, sym speeds)-parasympathetic controls more. Intrinsic hr (heart beating with no external influence) is 100 beats/min. But sympathetic neurons influence sa node, av node, Ventricular myocardium: increases hr and speeds conduction velocity, increases na permeability through f type channels, and more rapid depolarization. Parasympathetic neurons influence sa node and av node: causes hyperpolarization of sa cells by increasing k permeability, hyperpolarizing; also reduced na permeability through influencing f- type na channels, parasympathetic slows hr and slows conduction velocity.