6.2 PEx: Cardiovascular Physiology Lab Part 2

Part A

When vagus nerve stimulation was applied to the frog heart, _______.
    the force of contraction decreased and the heart rate slowed and eventually stopped
    the heart rate slowed and eventually stopped
    the force of contraction increased and the heart rate slowed and eventually stopped
    the force of contraction increased
    the force of contraction decreased

Part B

What part of your tracing illustrates vagal escape?
    the part where the force of contraction decreased
    the part where the heart rate slowed down
    the part where the heart resumed beating
    the part where the heart stopped

Part C

Research shows that in the absence of neural and hormonal influences, the SA node generates action potentials at a frequency of about 100 times per minute. However, the resting heart rate is about 70 beats per minute. What would the approximate heart rate be if the vagus nerve were severed?
    slower than 70 beats per minute
    about 100 beats per minute
    about 70 beats per minute
    faster than 100 beats per minute

Part D

Which of the following has the fastest rate of spontaneous depolarization?
    AV bundle branches
    the SA node
    the AV node
    Purkinje fibers