PNB 2265 Lecture 10: Lecture 10
8 Feb 2017
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The second heart sound (s2, dupp), occurs: Variations in heart rate and stroke volume change cardiac output. Pacemaker are innervated autonomic and are adrenergic hormones. Can control both stroke volume and heart rate speed. Not good at changing stroke volume, only heart rate. If you block parasympathetic: increase in basal heart rate in a person. The vagus nerve decreases heart rate by decreasing the rate of sa node filling. In the heart, ne/e bind beta adrenergic receptors g-protein coupled receptors (gs) Beta receptors on heart to respond to epi and norepi*** Aorta has the most volume, going to smaller arterioles and capillaries, where exchange occurs veins (decrease pressure) Opposition to flow caused b friction between blood and walls of blood vessels. If you had thicker blood (polycythemia), more resistance. Very small changes in r big change in r. More tension on walls of very large vessels aneurisms ( swelling of bv ) tend to occur in large vessels.
