Mammalian Heart and Blood Vessels

Review Questions

The heart’s internal pacemaker beats by:

  1. an internal implant that sends an electrical impulse through the heart
  2. the excitation of cardiac muscle cells at the sinoatrial node followed by the atrioventricular node
  3. the excitation of cardiac muscle cells at the atrioventricular node followed by the sinoatrial node
  4. the action of the sinus

Hint:

B

During the systolic phase of the cardiac cycle, the heart is ________.

  1. contracting
  2. relaxing
  3. contracting and relaxing
  4. filling with blood

Hint:

A

Cardiomyocytes are similar to skeletal muscle because:

  1. they beat involuntarily
  2. they are used for weight lifting
  3. they pulse rhythmically
  4. they are striated

Hint:

D

How do arteries differ from veins?

  1. Arteries have thicker smooth muscle layers to accommodate the changes in pressure from the heart.
  2. Arteries carry blood.
  3. Arteries have thinner smooth muscle layers and valves and move blood by the action of skeletal muscle.
  4. Arteries are thin walled and are used for gas exchange.

Hint:

A