Question

Discuss the influence of the venous system and arterial system on cardiac function and the mechanisms by which a denervated heart can increase its output during exercise.

Answer 1

Cardiac function implies cardiac output .
Cardiac output = Heart rate x stroke volume
Basically Cardiovascular system also known as Circulatory system is closed system .It consists of heart and vascular system whose main function is to distribute the blood to different parts of body .

Effect of venous sytem on cardiac function - Venous sytems consits of venous vessels which are capacitance vessels means they can accomadate more amount of blood in it so if venous return to heart increases it will increase the Flow of blood of blood to heart and further increasing cardiac output and vice versa.

Effect of arterial system on cardiac function -Arterial vessels are resistance vessels means they will not allow more amount of blood to accomodate in it so if pressure increases in arterial system cardiac output decrease and vice versa

Normally during exercise sympathetic activity increases which will increase the heart rate in normally healthy individuals.
In case of denervated individual ( Heart transplanted pateint ) Resting heart rate is more as Vagal inhibition of Sinoatrial node is not present and further increase during exercise is due to release of cathecholamones ( Adrenaline ) from adrenal glands which act on receptors of heart and Increase the heart rate but increase in heart rate is less as compared to normal healthy heart .