Understanding Cardiac Output

Cardiac output is the volume of blood the heart pumps to maintain health, determined by heart rate and stroke volume. Stroke volume is influenced by the blood volume in the heart before contraction, heart size, and stretchability. Ejection fraction, the percentage of blood pumped out during a heartbeat, depends on the heart's strength and the resistance in arteries. The remaining blood post-contraction is termed end-systolic volume.

What two main factors determine cardiac output?

• Arterial pressure and heart elasticity

• Heart rate and stroke volume

• Blood pressure and heart size

• Ejection fraction and venous return

Which factor influences the amount of blood in the heart before it contracts?

• Ejection fraction

• Venous return

• Heart rate

• Blood pressure

How does heart size affect stroke volume?

• Larger hearts have lower stroke volume

• Smaller hearts have higher stroke volume

• Heart size does not affect stroke volume

• Larger hearts can accommodate more blood, increasing stroke volume

What is the term for the blood remaining in the heart after it contracts?

• Ejection fraction

• End-systolic volume

• Stroke volume

• Cardiac output

What does ejection fraction measure?

• The total blood volume in the body

• The proportion of blood pumped out of the heart

• The heart's contraction strength

• The blood pressure in arteries