Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The cardiac output is generally represented in relation to the body's surface area (cardiac output/body surface area).
Reason (R): The cardiac output increases in direct proportion to the surface area of the body.
In the light of the above statements, choose the most appropriate answer.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Cardiac Index = CO BSA Used to compare heart function across different body sizes

Answer 1

The Correct Option is A

Concept:
Cardiac Output (CO) is the volume of blood pumped by the heart per minute. To compare individuals of different body sizes, CO is often normalized using Body Surface Area (BSA), giving: \[ \text{Cardiac Index} = \frac{\text{Cardiac Output}}{\text{Body Surface Area}} \]

Step 1: Understanding Assertion (A).
The assertion states:
• CO is represented relative to body surface area This is correct because:
• It standardizes values across individuals
• Known as Cardiac Index

Step 2: Understanding Reason (R).
The reason states:
• Cardiac output increases with body surface area This is also correct because:
• Larger individuals require more blood supply
• Hence, CO is higher

Step 3: Linking A and R.
Since CO varies with body size:
• It is normalized using BSA Thus:
• Reason correctly explains Assertion

Step 4: Conclusion.
\[ \boxed{\text{Both A and R are correct and R explains A}} \]