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4 years ago
Does anyone have the answer to Physioex 9.0 Exercise 6 Cardiovascular Physiology Activities 1 & 2 questions 1-16?? anything would be greatly appreciated!!! Thanks!!

ACTIVITY 1:  Investigating the Refractory Period of
Cardiac Muscle
1.   Which of the following types of muscle tissue can depolarize spontaneously in the absence of any external stimulation:
a.   Skeletal muscle
b.   Smooth muscle    
c.   Cardiac muscle
d.   All of the above
2.   Look at Figure 6.1, the cardiac action potential.  The period of time between the beginning of the cardiac action potential and the approximate middle of phase 3 is the __________________ refractory period of cardiac muscle.
3.   In this simulation, when you delivered several single stimuli very rapidly, you saw a double peak.  The second peak is called an ______________.
4.   True or False:  In order for the heart to function the most effectively in pumping blood, the ventricles must contract and then relax fully with each beat.
5.   Explain why the larger waves seen on the oscilloscope represent ventricular contractions.
6.   Explain why the amplitude of the wave did not change when you increased the frequency of the stimulation.  (HINT: Relate your response to the refractory period of the cardiac action potential.)
7.   Why is it only possible to induce an extra systole during relaxation.
8.   Explain why wave summation and tetanus are not possible in cardiac muscle tissue.
ACTIVITY 2:  Examining the Effect of Vagus Nerve Stimulation
9.   Cranial nerve 10, the vagus nerve, is an important part of which nervous system…the sympathetic or parasympathetic?

10.   True or False:  Both the sympathetic nervous system and the parasympathetic nervous system can cause the heart rate to change and affect the strength of contraction of the heart. 
11.   In this simulation, at rest the frog heart was “beating” at ______ beats/minute.  After stimulation with the vagus nerve at 50 times/minute, the heart rate ___________.
12.   Both the vagus nerve and a branch of the sympathetic nervous system innervate the
a.   heart muscle.
b.   sinoatrial (SA) node.
c.   bundle of His.
d.   Purkinje fibers.
13.   Explain the effect that extreme vagus nerve stimulation had on the heart.
14.   The SA node of the heart is located in the muscle of the ______  _______.  (HINT:  Which chamber?)
15.   Describe how the sympathetic and parasympathetic nervous systems work together to regulate the heart rate.
16.   What do you think would happen to the heart rate if the vagus nerve were surgically cut?
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Staff Member
4 years ago
Best to follow the forum rules and post one question per thread. Otherwise you won't get the attention of trusted members.
- Master of Science in Biology
- Bachelor of Science (Biology)
- Bachelor of Education
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