Summer Lecture Circulation 1 final

friday july 20 12 modulaon of the heart rate

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Unformatted text preview: e – The EKG is an important diagnostic tool since the signal is directly related to the performance of specific nodal, conducting, and contractile components of the heart Friday, July 20, 12 Myogenic Hearts • While all heart muscle can undergo rhythmic depolariza(ons specialized cardiac muscle cells acts as a pacemaker – Cells in S- A node have poorly developed contrac(le proper(es – However, the cells of the S- A node exhibit a high frequency of spontaneous depolariza(ons Pace maker Friday, July 20, 12 Start and Spread of Depolariza(on During a Heartbeat • Depolariza(on starts in the S- A node • Spreads rapidly through atrial muscle • Signal blocked from spreading into the ventricular muscle by a layer of non- conduc(ve (ssue • Signal can only spread to the ventricular muscle via the A- V node a`er a delay • The A- V node routes the depolariza(on to the most ventral region of the ventricles???? Friday, July 20, 12 Modula(on of the Heart Rate • Sympathe(c and parasympathe(c neur...
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