Exercise 6: Cardiovascular Physiology: Activity 2: Examining the Effect of Vagus Nerve Stimulation Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. The effect of the parasympathetic nervous system on the heart is to You correctly answered: a. decrease the heart rate. 2. The branch of the autonomic nervous system that dominates during exercise is You correctly answered: b. the sympathetic branch. 3. Parasympathetic stimulation reaches the heart through You correctly answered: d. vagus nerves, which are cranial nerves. 4. The usual pacemaker of the heart You correctly answered: c. is the sinoatrial node.
Experiment Results Predict Question: Predict Question: What do you think will happen if you apply ...view middle of the document...
signals that decrease the heart rate. 3. Enter the number of ventricular contractions per minute (from the heart rate display) in the field below and then click Submit Data to record your answer in the lab report. You answered: 59 beats/min The response that resumed the heartbeat after the vagus nerve stimulation is called You correctly answered: b. vagal escape. Experiment Data:
Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. Extreme vagus nerve stimulation affects the heart by You correctly answered: a. stopping the heart completely. 2. Vagal escape probably involves You correctly answered: c. sympathetic reflexes. 3. Research shows that, in the absence of neural and hormonal influences, the SA node generates action potentials at a frequency of approximately 100 times per minute. However, the resting heart rate is approximately 70 beats per minute, which suggests that You correctly answered: b. the parasympathetic nervous system has more control over heart rate. 4. The SA (sinoatrial) node in the human heart is located You correctly answered: c. in the right atrium
Review Sheet Results 1. Explain the effect that extreme vagus nerve stimulation had on the heart. How well did the results compare with your prediction? Your answer: The HR decreased and stopped temporarly. 2. Explain two ways that the heart can overcome excessive vagal stimulation. Your answer: 1. Initiation of ta rythm by the purkinge fiber 2. Sympathetic reflexes 3. Describe how the sympathetic and parasympathetic nervous systems work together to regulate heart rate. Your answer: Smpathetic increases HR Parasympathetic decreases HR 4. What do you think would happen to the heart rate if the vagus nerve was cut? Your answer: It would increase and go back to 100bpm