In: Anatomy and Physiology
1. Explain the following.
a. Compare the right and left ventricular pressures and right and left ventricular volumes.
b. What will happen to cardiac output during exercise? Explain what physiological changes occur that cause this change in cardiac output?
Answer 1:
a: The pressure in the left ventricle is more than the right ventricle. The walls of left ventricle is thicker than the right ventricle as the left ventricle has to pump blood to all parts of the body against high pressure and hence left ventricular pressure is more.
On the other hand right ventricular volume and left ventricular volume is almost same and there is not much of a difference. The stroke volume of right and left ventricle is approximately 70 ml for a healthy 70 kg man.
b: During exercise the oxygen demand by the exercising muscle increases and the muscles requires more oxygenated blood. To supply more blood to the exercising muscles the sympathetic activity increases due to which contractility of the heart increases which increases the heart rate and the stroke volume. The increased heart rate and increased stroke volume increases the cardiac output reqiured to supply more oxygenated blood to the muscles during exercise. Hence the cardiac output increases during exercise.
Cardiac output depends upon heart rate and stroke volume:
Cardiac output(CO)= Heart rate (HR) x Stroke Volume (SV)