EXSS2028 Lecture Notes - Lecture 9: Sucks Blood, Thoracic Diaphragm, Afterload

• School: University of Sydney
• Department: Exercise and Sport Science
• Course: EXSS2028
• Professor: Kieron Rooney

Document Summary

Muscle metabolites & local vasodilation: blood metabolites (adenosine, low po2, high pco2, high h+, high k+) act on arterioles. Cause vasodilation increase blood flow: chemical substances from endothelium (nitric oxide is a vasodilator & release is stimulated by catecholamines from endothelium) act on arterioles cause vasodilation. Dynamic & isometric exercise [types]: dynamic: alternating contraction & relaxation of muscles, running, walking, cycling, swimming, upper body vs. lower body exercise. Cardiac output: graph (for one person, not several subjects) should be linear; otherwise several subjects = curvilinear. Determinants of exercise stroke volume: need high preload (volume in left ventricle at end of diastole) high preload causes greater stretch of ventricle, increased diastolic filling (preload) Afterload: blood into the aorta: force (cid:523)(cid:498)myocardial stress(cid:499)(cid:524) which the ventricle must generate & sustain in order to eject, end diastolic load / ventricular load, how hard the myocardium contracts to overcome vascular resistance in the aorta/arterial system.