Question

1) If Lucy had all of the pacemaker cells in her AV node die off, what would happen?

A. Her heart would still beat at a normal rate as if nothing happened.
B. Her heart would stop beating and she would die.
C. Her heart rate would be controlled by the pacemaker cells of the Bundle of His . Her heart rate would start depolarizing from the apex.
D. Her heart would still beat, but the ventricles would contract right before the atria, instead of the opposite.

2) Which of the following is a true statement about capillaries?

A. At the efferent end, osmotic pressure is usually less than hydrostatic pressure.
B. They are leaky to everything but plasma and red blood cells.
C. Most of the water that leaves the capillary via ultrafiltration is brought back into the capillary via reabsorption.
D. All of the above are true.
E. None of the above is true.

3) Which of the following is a true statement?

A. The endocardium is the muscle layer of the heart.
B. The epicardium is a thick fibrous layer that is filled with fluid.
C. Without any autonomic N.S. influence, a heart would contract at ~70-80 beats per minute.
D. All of the above are true.
E. None of the above is true.

4) If Brown was injected with a drug that blocked all autonomic signalling to the heart, what would happen to him?

A. His heart would stop beating and he would die.
B. His heart would still beat, but much slower than a normal person's.
C. His heart would beat at about 50-60 beats per minute
D. He would be unaffected because the autonomic nervous system doesn't go to the heart.
E. His heart rate would remain a constant 70-80 beats per minute regardless if he was resting or exercising.

5) Brown is injected with a drug that blocks all of the voltage-gated Ca2+ channels, but only on his myocardial cells. What will happen to Brown?

A. His heart rate will increase dramatically.
B. His heart will contract with more force.
C. The pacemaker cells will no longer be able to fire action potentials.
D. His heart would stop contracting at all.
E. He would be unaffected, because there are no voltage-gated channels on myocaridal cells.

Answer 1

Answer:

1) If Lucy had all of the pacemaker cells in her AV node die off, what would happen?

C. Her heart rate would be controlled by the pacemaker cells of the Bundle of His . Her heart rate would start depolarizing from the apex.

2) Which of the following is a true statement about capillaries?

C. Most of the water that leaves the capillary via ultrafiltration is brought back into the capillary via reabsorption.

3) Which of the following is a true statement?

E. None of the above is true.

4) If Brown was injected with a drug that blocked all autonomic signalling to the heart, what would happen to him?

E. His heart rate would remain a constant 70-80 beats per minute regardless if he was resting or exercising.

5) Brown is injected with a drug that blocks all of the voltage-gated Ca2+ channels, but only on his myocardial cells. What will happen to Brown?

E. He would be unaffected, because there are no voltage-gated channels on myocaridal cells.

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