PSL301H1 Chapter Notes - Chapter 5: Inotrope, Stroke Volume, Myocyte
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PSL301H1 Full Course Notes
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Length of muscle fibers at the beginning of contraction. Contractility: intricacies ability of a cardiac muscle fibre to contract at any given fibre length. Length-tension relationships and the frank-starling law of the heart. Longer the muscle fibre, greater the strength. Preload degree of myocardial stretch before contraction begins. Starling curve depicts relationship between tech and force. X: end-diastolic volume: a measure of stretch in the ventricles -->determined sarcomere length. Y: stroke volume (cid:314) indicate force of contraction. Frank-starling law of the heart: more blood (cid:314) contracts stronger to eject more blood: the heart pumps all the blood. End-diastolic volume determined by venous return: the amount of blood than enter the heart from the venous circulation. Contraction of veins returning blood to the hear. Pressure changes in the thorax during breathing. Skeletal pump: return blood to the heart. Contractility is controlled by the nervous and endocrine systems. Note that contractility is distinct from the length-tension relation tipno.
