Intrinsic Cardiac Activity : The First Peak Of The Electrocardiogram Graph

766 Words Mar 30th, 2016 4 Pages
Intrinsic Cardiac Activity: The first peak of the electrocardiogram graph corresponded to the atrial contraction of the heart. The second peak of the electrocardiogram graph corresponded to the ventricular contraction of the heart. The third peak observed corresponded to the relaxation of the heart.
Frank-Starling Mechanism: There was no significant trend observed in ventricular contractile force in response to increasing imposed length of the heart (Fig 1a). A maximum ventricular contractile force of 0.0032 + 0.001039 N (N=3) was generated at an imposed length of 4 mm. A minimum ventricular contractile force of 0.00137 + 0.0000577 N (N=3) was generated at an imposed length of 0 mm.
There was no significant trend observed in heart rate in response to increasing imposed length of the heart (Fig 1b). A minimum heart rate of 31.7 + 0.577 beats/min (N=3) was generated at an imposed length of 7 mm. A maximum heart rate of 36.7 + 0.577 beats/min (N=3) was generated at an imposed length of 6 mm.
Autonomic Control of the Heart: A significant decrease in ventricular contractile force was observed in the heart after the addition of epinephrine, eserine, and acetylcholine to the heart, however, no significant change in ventricular contractile force was observed after the addition of atropine (Fig. 2a). A maximum ventricular contractile force of 0.00137 + 0.0000577 N (N=3) was observed upon no additions. Following the addition of epinephrine, a significant decrease of ventricular…

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