The cardiac muscle is capable of which of the following? - ANSautorhythmicity
Phase 2 of the cardiac action potential, when the Ca channels remain open and potassium
channels are closed, is called the... - ANSPlateau Phase
Which of the following is true of cardiac action potential? - ANSThe cardiac action potential is
longer than the skeletal muscle action potential
The main anatomical difference between the frog heart and the human heart is that the frog
heart has.... - ANSa single, fused ventricle
What is true about contractile activity? - ANSThe smaller waves represent the contraction of the
atria
When you increase the frequency of stimulation to the frog heart, what will happen to the
amplitude (height) of the ventricular systole wave? - ANSThe amplitude will not change
During which portion of the cardiac muscle contraction is it possible to induce an extrasystole? -
ANSDuring relaxation
If you deliver multiple stimuli to the heart (20 per second) what do you think will happen? -
ANSneither wave summation nor tetanus
The amplitude of the ventricular systole did not change with more frequent stimulation
because... - ANSA new contraction could not begin until the relaxation phase
Which of the following do you think contribute to the inability of cardiac muscle to be tetanized -
ANSthe long refractory period of the cardiac action potential
Given the function of the heart, why is it important that cardiac muscle cannot reach tetanus? -
ANSThe ventricles must contract and relax fully with each beat to pump blood
An extrasystole corresponds to... - ANSan extraventricular contraction
The effect of the parasympathetic nervous system on the heart is to... - ANSDecrease the heart
rate (not decrease the force of contraction)
The branch of the autonomic nervous system that dominates during exercise... - ANSthe
sympathetic branch