Question

Assertion (A): There is no mixing of oxygenated and deoxygenated blood in the human heart.

Reason (R): Valves are present in the heart which allows the movement of blood in one direction only.

Options

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer 1

Both A and R are true but R is not the correct explanation of A.

Explanation:

The assertion is true because the human heart is structurally divided into completely separate right and left sides by muscular walls called septa, preventing any mixing of oxygenated and deoxygenated blood. The reason is also true because internal valves (like the bicuspid, tricuspid, and semilunar valves) ensure that blood flows strictly in a unidirectional path, blocking any backflow. However, the reason is not the correct explanation of the assertion, as a valve's function is to prevent backflow within a chamber or vessel, whereas the interatrial and interventricular septa physically keep the two distinct types of blood from mixing.