Question

What compensatory measures does the body employ in an attempt to restore cardiac output? What are the effect of these compensatory measures?

Answer 1

CARDIAC OUTPUT: Cardiac output is the amount of blood your heart is able to pump in 1 minute.

HEART FAILURE AND COMPENSATION: Heart failure is a chronic, progressive condition in which the heart muscle is unable to pump enough blood to meet the body's need for blood and oxygen. Because the heart cannot pump well, the heart and body try to make up for it. This is called as compensation. With heart failure, the weekened heart supply less blood to the cells which results in fatigue, shortness of breath and some people complaints of having cough.

HOW DOES THE BODY COMPENSATE? With heart failure, the heart does not pump as well as it should which results in less amount of blood and oxygen supply in the body. When this occurs, the body's hormone and nervous system try to supply enough blood and oxygen to the body by a) increasing blood pressure b) holding water and salt in the body and c) by increasing heart rate.

NERVOUS SYSTEM : If your body senses that there is less amount of blood supply in the body, the brain and in other major vital organs, the sympathetic nervous system releases a substance called catecholamines into the bloodstream. This substance cause the blood vessels to constrict and increases the heart rate. On the other side, the arteries supplying the blood to the brain and other vital organs widen to carry the increased blood flow.

HORMONES: When the body needs more fluid in its blood vessels, it releases specific chemicals like renin, angiotensin and aldosterone which causes the blood vessels to constrict. Moreover, these hormones retain more sodium ( salt) and water resulting in more amount of fluid in the circulatory system. This fluid becomes part of the blood circulating throughout the system.

WHAT ARE THE EFFECT OF THESE COMPENSATORY MEASURES? A) Compensation can make heart failure worse by further enlarging the heart and reduces the pumping ability of the heart over time.