Cardiac Cycle & Control of Rhythm

Cardiac Cycle & Control of Rhythm - 5 Basic...

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AP Biology Cardiac Cycle & Control of Rhythm - Cardiac Cycle = One rhythmic cycle of the heart contraction and relaxation is heart cycle – 0.8 seconds 1) It consists of systole and diastole a) Systole = contraction stage b) Diastole = relaxation stage 2) This is controlled by pacemaker (SA node), which is located right under the right atrium. 3) Pulse = the direct measure of the arteries for heart beat 4) Two hormones are involved in cardiac cycle by medulla a) Epinephrine increases the heart beat from sympathetic nervous system b) Acetylcholine decreases the heart rate from parasympathetic nervous system
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Unformatted text preview: 5) Basic Mechanism of Heart Cycle a) Ventricle contraction Ventricle contracts Atrium relaxes → Blood will come in b) Atrium contraction Atrium contracts → Blood will exit Ventricle relaxes c) SA valve opens / AV valve closes Atrium Relax Atrium and ventricles contract SA valve closes / AV valve opens-Control of Rhythm a) Pacemaker (SA node) generates the electrical signal b) Signals are delayed at AV node c) Signals reach to heart apex d) Signals spread throughout ventricles by Purkinje fibers...
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