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1.Explain why the larger waves seen on the oscilloscope represent ventricular contraction?
2. Explain why the amplitude of the wave did not change when you increased the frequency of the stimulation?
3. Why is it only possible to induce an extrasystole during relaxation?
4. Explain why wave summation and tetanus are not possible in  cardiac muscle tissue?
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1.  The ventricular contraction is of greater force than the atrial contraction, since the ventricular contraction functions to send blood throughout the entire body (systemic circulation), where as the contraction of the atrium send blood only to the lungs and rest of the the heart (pulmonary circulation).
2. The maximum threshold will not change in cardiac muscle cells (as with any other cells), which is determined by the X amount of voltage needed for calcium channels to open.  After this point, no additional voltage can cause the channels to open more, or again, prior to depolarization.
3. cardiac is able to depolarize only after repolarization
4. Cardiac cells have long action potentials and long twitches, therefore do not show temporal summation
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5 years ago
@cotypatricie: Great answer.

@jj889: Please mark as solved.
- Master of Science in Biology
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