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 contractile force from 0.00137 + 0.0000577 N (N=3) to 0.00103 + 0.000153 N (N=3) was observed. A significant decrease of ventricular contractile force from 0.00137 + 0.0000577 N (N=3) to 0.000833 + 0.0000577 N (N=3) was observed after the addition of eserine. After the addition of atropine, no significant difference in ventricular contractile force was observed when compared to the baseline value. Following the addition of acetylcholine, a significant decrease in ventricular contractile force from 0.00137 + 0.0000577 N (N=3) to 0.000767 + 0.000153 N (N=3) was observed. This was also the minimum ventricular contractile force observed. A significant increase in heart rate was observed after the addition of epinephrine and atropine to the heart, but not after the addition of eserine and acetylcholine (Fig. …show more content…
2b). A minimum heart rate of 33.7 + 0.577 beats/min (N=3) was observed with no additions. After the addition of ephinephrine, a significant increase in heart rate from 33.7 + 0.577 beats/min (N=3) to 37.7 + 0.577 beats/min (N=3) was observed. After the addition of eserine, no significant difference in heart rate was observed relative to the baseline value. Following the addition of atropine, a significant increase in heart rate from 33.7 + 0.577 beats/min (N=3) to 37.7 + 0.577 beats/min (N=3) was observed. No significant difference in heart rate was observed after the addition of acetylcholine relative to the baseline value. The maximum heart rate of 37.7 + 0.577 beats/min (N=3) was both observed after the addition of ephinephrine and atropine. Influence of Temperature on Cardiac Activity: A significant increase in ventricular contractile force was observed following the addition of Ringer’s solution at a temperature of 40⁰C to the heart (Fig 3a). A maximum ventricular contractile force of 36.7 + 2.52 N (N=3) was observed after the addition of Ringer’s solution at a temperature of 40⁰C. A minimum ventricular contractile force of 32 + 1 N (N=3) was observed after the addition of Ringer’s solution at a temperature of 4⁰C. A significant increase in heart rate was observed in response to increasing Ringer’s solution temperature applied
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 contractile force from 0.00137 + 0.0000577 N (N=3) to 0.00103 + 0.000153 N (N=3) was observed. A significant decrease of ventricular contractile force from 0.00137 + 0.0000577 N (N=3) to 0.000833 + 0.0000577 N (N=3) was observed after the addition of eserine. After the addition of atropine, no significant difference in ventricular contractile force was observed when compared to the baseline value. Following the addition of acetylcholine, a significant decrease in ventricular contractile force from 0.00137 + 0.0000577 N (N=3) to 0.000767 + 0.000153 N (N=3) was observed. This was also the minimum ventricular contractile force observed. A significant increase in heart rate was observed after the addition of epinephrine and atropine to the heart, but not after the addition of eserine and acetylcholine (Fig. …show more content…
2b). A minimum heart rate of 33.7 + 0.577 beats/min (N=3) was observed with no additions. After the addition of ephinephrine, a significant increase in heart rate from 33.7 + 0.577 beats/min (N=3) to 37.7 + 0.577 beats/min (N=3) was observed. After the addition of eserine, no significant difference in heart rate was observed relative to the baseline value. Following the addition of atropine, a significant increase in heart rate from 33.7 + 0.577 beats/min (N=3) to 37.7 + 0.577 beats/min (N=3) was observed. No significant difference in heart rate was observed after the addition of acetylcholine relative to the baseline value. The maximum heart rate of 37.7 + 0.577 beats/min (N=3) was both observed after the addition of ephinephrine and atropine. Influence of Temperature on Cardiac Activity: A significant increase in ventricular contractile force was observed following the addition of Ringer’s solution at a temperature of 40⁰C to the heart (Fig 3a). A maximum ventricular contractile force of 36.7 + 2.52 N (N=3) was observed after the addition of Ringer’s solution at a temperature of 40⁰C. A minimum ventricular contractile force of 32 + 1 N (N=3) was observed after the addition of Ringer’s solution at a temperature of 4⁰C. A significant increase in heart rate was observed in response to increasing Ringer’s solution temperature applied