03b Cardiac Cycle

What is the average heart rate for an adult?

• 50 beats per minute

• 60 beats per minute

• 70 beats per minute

• 80 beats per minute

How long does a complete cardiac cycle take at an average heart rate?

• 0.6 seconds

• 0.8 seconds

• 1 second

• 1.2 seconds

What is the main function of the cardiac cycle?

• To regulate blood pressure

• To circulate oxygen

• To fill the heart with blood and pump it out to the pulmonary and systemic circuits

• To control heart rate

During atrial systole:

• The ventricles contract

• The atria relax

• Blood is pumped into the aorta

• Blood is forced into the ventricles

What happens when the ventricles contract during ventricular systole?

• Blood is ejected into the atria

• The AV valves open

• The semilunar valves open

• Blood flows passively into the ventricles

What occurs during cardiac diastole?

• The atria contract

• Blood is ejected from the ventricles

• The heart chambers relax and fill with blood

• The semilunar valves close

The contraction of the heart muscle is known as:

• Diastole

• Systole

• Isovolumetric contraction

• Relaxation

The relaxation of the heart muscle is referred to as:

• Diastole

• Systole

• Isovolumetric contraction

• Ventricular ejection

What percentage of blood in the atria flows passively into the ventricles during cardiac diastole?

• 50%

• 60%

• 70%

• 80%

What is the function of the semilunar valves?

• To prevent backflow into the atria

• To allow blood to flow from the ventricles into the aorta and pulmonary artery

• To prevent blood from entering the pulmonary veins

• To regulate heart rate