LO9: Define cardiac output and factors that influence it

What is cardiac output (CO)?

The volume of blood the heart pumps per minute.

What is the equation for cardiac output?

CO = Heart Rate (HR) × Stroke Volume (SV).

What does Heart Rate (HR) mean in the cardiac output equation?

The number of heartbeats per minute.

What does Stroke Volume (SV) mean in the cardiac output equation?

The amount of blood pumped by the left ventricle with each beat.

What happens to cardiac output if heart rate increases?

Cardiac output increases (if stroke volume stays the same).

What happens to cardiac output if stroke volume decreases?

Cardiac output decreases (if heart rate stays the same).

Name some factors that can increase stroke volume.

Increased venous return, stronger heart contractions, and decreased afterload.

How does increased venous return affect cardiac output?

It increases stroke volume and thus cardiac output.

How does very high heart rate affect cardiac output?

It can decrease cardiac output because ventricles don’t have enough time to fill.