lecture 13 Cardiovascular sq key - Short Answers to Lecture...

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Short Answers to Lecture 13 Study Questions 1. a. What events in the heart cause the ‘Lub-dub’ heart sounds S1 and S2? S1 (Lub) is caused by the atrioventricular (AV) valves closing, and S2 (dub) is caused by the aortic and pulmonary valves closing. b. Can you estimate the durations of systole and diastole at rest from your own heart sounds? Yes, and you should right now if you didn’t! Systole is the period between S1 and S2, and diastole is the period between S2 and the next S1. For me, the period between one lub and the next is about 1 second at rest, and systole lasts about ¼ of a second (I clap four times for per heartbeat, with lub on 1 and dub on 2). c. How would you expect the durations of systole and diastole to change as heart rate increases (e.g. during exercise)? Both systole and diastole should get faster, but the duration of diastole has more scope for change, as it is longer at rest. During hard exercise, the period between my heartbeats is about 3/8 second, and the lubs and dubs are more equally spaced, so
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This note was uploaded on 05/07/2010 for the course INTEG BIO 132 taught by Professor Lehman during the Spring '10 term at University of California, Berkeley.

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lecture 13 Cardiovascular sq key - Short Answers to Lecture...

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