Question

Which of the following would have the same $O_2$ content?

• A. Blood entering the lungs and blood leaving the lungs.
• B. Blood entering the right side of the heart and blood leaving the right side of the heart.
• C. Blood entering the right side of the heart and blood leaving the left side of the heart.
• D. Blood entering the tissue capillaries and blood leaving the tissue capillaries.

Answer 1

The correct option is B

Blood entering the right side of the heart and blood leaving the right side of the heart.

Blood entering the right side of the heart i.e., the right atrium is deoxygenated blood having $P{O}_2–40$ mmHg. Blood leaving the right side of the heart i.e., from the right ventricle will also have the same partial pressure as no exchange of gases occurs in this path.