Question

Match each definition to the appropriate term. Not all definitions will be used. Preload Afterload Venous return Answer Bank amount of pressure a ventricle must produce to eject blood amount of blood in a ventricle during diastole amount of blood returning to the heart extent of cardiac muscle cell stretch before a contraction

Answer 1

Answer

1) Preload -- Extent of cardiac muscle stretch before a contraction

• The amount of blood in the ventricle before it starts to contract s called end diastolic volume. EDV determines the preload.
• Increased EDV increases preload.

2) Afterload -- Amount of pressure a ventricle must produce to eject the blood

• In order for a ventricle to contract, it need to produce a pressure greater than the atrial pressure.
• Hence, the amount of pressure ventricle produces to overcome the atrial pressure is called afterload.

3) Venous return -- Amount of blood returing to the heart

• The amount of blood that heart receives back is venous return.
• Normally venous return has to be equal to the cardiac output.