BIOL 2002C 1st Edition Lecture 9 Outline of Current Lecture I Exam 2 for first hour II Cardiac Output Activity Current Lecture Stroke Volume EDV ESV Example EDV 120 mL beat ESV is 50 mL beat what is the stroke volume 120mL 50mL 70 mL Stroke Volume is 70 mL beat Cardiac Output Stroke Volume x Heart Rate Example HR is 72 beats minutes stroke volume is 70 mL beat what is the cardiac output 72 beats minute x 70 mL beat 5040 mL minute How does exercise affect Heart Rate It increases heart rate due to activation of the sympathetic nervous system How does exercise affect Stroke Volume It increases stroke volume because exercise promotes increased venous return This also would cause EDV to increase thus increasing the stroke volume Sympathetic stimulation also increased cardiac contractility which decreases the ESV therefore also increasing SV How does exercise increase the cardiac output Since Cardiac Output HR X SV and both HR and SV increased CO must also increase How does severe blood loss affect stroke volume It would decrease the stroke volume because EDV preload would decrease How would severe blood loss affect heart rate Increase the HR because the body is trying to compensate for the reduced stroke volume to maintain cardiac output These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute How did blood loss affect the cardiac output The cardiac output would decrease if blood loss continues even though HR is trying to compensate for the decreased SV How does verapamil which is a calcium channel blocker that affects cardiac muscle cells effect SV and CO SV will decrease because contractility will be decreased due to the calcium channel being blocked in contractile cells this increases the ESV HR will also decrease because calcium is needed for depolarization in autorhythmic cells thus will decreased HR and decreased SV CO will also decrease Who would this drug be prescribed for Tachycardia patients and Patients with congestive heart failure because it keeps the damaged heart from over working How does atherosclerosis affect stroke volume Atherosclerosis is the narrowing of the arteries so the heart is trying to force blood out a smaller diameter which increases the resistance which increases the blood pressure The increased BP will increase the afterload factor ESV The increased ESV therefore decreases the SV How does atherosclerosis affect the HR Once SV begins to decrease the body will try and compensate by increasing HR to maintain proper CO How does atherosclerosis affect the HR Since this is a chronic condition the body will do its best to maintain CO by increasing HR to compensate for the decreased SV