Cardiovascular Physiology Exercise 6

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Explan why the larger waves seen on the oscilloscope represent ventricular contraction| the ventricle contraction is of greater force than the atrial contraction, this is due to the fact that ventricle's fxn is to send blood throughout the body.| Explain why the amplitude of the wave did not change when you increased the frequency of the stimulation in cardiac muscle.| amplitude does not change because the cardiacs long refractory period prevents summation.| Why is it only possible to induce an extrasystole during relaxation?| the extrasystole can not occur until relaxation and so we could not achieve wave summation tetanus| Explain why wave summation and tetanus are not possible in cardiac muscle tissue.| Cardiac cells have longer APs and twitches than any other muscle cells,therefore they do not show temporal summation| explain the effect that extreme vagal stimulation had on the heart.| the HR decreases and stopped the heart temporarily| Explain two ways that the heart can overcome excessive vagal stimulation.| 1: Sympathetic reflexes 2: initiation of a rhythm by the Purkinje Fibers|

Describe how the sympathetic and parasympathetic nervous system work together to regulate heart rate| Sympathetic increases HR Parasympathetic decreases HR|
What do you think would happen to the HR if the vagus nerve was cut?| It would increase and go back to the 100bpm| Explain the effect that decreasing temperature had on the frog heart.| It slows the HR| Describe why Ringer's solution is required to maintain heart contractions.| it contains all the ions, pH, glucose, ATP need to keep the heart beating.| Explain the effect that increasing the temperature had on the frog heart.| it increase the HR| describe the effect that pilocarpine had on the heart and why it had this effect| -It decreases the HR -it stimulates the parasympathetic nerves|

Atropine is an acetylcholine antagonist. Does atropine inhibit or enhance the...
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