2. The Heart Part Three

Question 1

What is the internodal tract?

Answer 1

connects the SA node to the AV node to allow action potentials to spread down the special conduction pathway

Question 2

What are Purkinje fibers?

Answer 2

fibers that allow impulse to spread rapidly and evenly over both ventricles

Question 3

How does the parasympathetic nervous system affect the heart?

Answer 3

continually inhibits depolarization of the SA node

Question 4

What is the vagus nerve?

Answer 4

cranial nerve; will release acetylcholine that inhibits the depolarization of the SA node by binding to receptors on the cells of the SA node

Question 5

What is the vagal tone?

Answer 5

constant level of inhibition provided by the vagus nerve

Question 6

How does the sympathetic nervous system influence the heart?

Answer 6

stimulatory by increasing heart rate and force of contraction during fight or flight

Question 7

What are baroreceptors?

Answer 7

special receptors that monitor pressure of the heart

Question 8

What will occur if baroreceptors realize pressure is too high?

Answer 8

tells the CNS which will increase vagal tone and decrease sympathetic output

Question 9

What will occur if baroreceptors realize pressure is too low?

Answer 9

tells the CNS which will decrease vagal tone and increase sympathetic output