Cardiac output

Question 1

What 4 factors affects cardiac output?

Answer 1

1. ) Preload
2. ) Afterload
3. ) Contractility
4. ) Heart rate (CO = SV X HR)

Question 2

What is preload?

Answer 2

The force in the heart when in diastoli and blood is entering the heart. Left ventricular end diastolic pressure = pressure in left ventricle when filling - to do with sarcomere length.
THIS IS CARDIAC FILLING PRESSURE - regulated by venous tone which is regulated by the SNS

Question 3

What is afterload?

Answer 3

The force the heart must overcome in order to pump blood out of the heart = needs to overcome the force of the systemic circulation
connected to SV = How much blood is being pumped out
Afterload is to do with TPR - THE GREATER THE RESISTANCE VESSEL TONE (tone in systemic circ) the greater the resistance/pressure when ejecting.

Question 4

What is contractility?

Answer 4

The hearts ability to contract and pump blood out