Question

Study the given diagram of the heart, with blood vessels marked '1' and '2'.
From the following statements, establish the relationship between heart and/or the two blood vessels:
(i) Blood vessel 1 - It carries carbon dioxide rich blood to the lungs.
(ii) Blood vessel 2 - It carries oxygen rich blood from the lungs.
(iii) Blood vessel 2 - Left atrium relaxes as it receives blood from this blood vessel.
(iv) Blood vessel 1 - Right atrium has thick wall as it has to pump blood to this vessel.

The option with correct statements is:

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (ii), (iii) and (iv)
• D. (i), (ii) and (iii)

Hint:

Heart anatomy facts:

• Pulmonary artery: Carries deoxygenated blood \textbf{to} lungs (exception: artery carries deoxygenated blood)
• Pulmonary vein: Carries oxygenated blood \textbf{from} lungs (exception: vein carries oxygenated blood)
• Atria are thin-walled receiving chambers
• Ventricles are thick-walled pumping chambers

Answer 1

The Correct Option is D

Step 1: Identify the blood vessels based on their functions.
Based on the descriptions:

• Blood vessel 1: Carries carbon dioxide rich blood to the lungs \(\Rightarrow\) This is the pulmonary artery.
• Blood vessel 2: Carries oxygen rich blood from the lungs \(\Rightarrow\) This is the pulmonary vein.

Step 2: Analyze each statement.

• (i) Blood vessel 1 - It carries carbon dioxide rich blood to the lungs: Correct. Pulmonary artery carries deoxygenated blood from right ventricle to lungs.
• (ii) Blood vessel 2 - It carries oxygen rich blood from the lungs: Correct. Pulmonary vein carries oxygenated blood from lungs to left atrium.
• (iii) Blood vessel 2 - Left atrium relaxes as it receives blood from this blood vessel: Correct. During atrial diastole, left atrium relaxes and receives blood from pulmonary veins.
• (iv) Blood vessel 1 - Right atrium has thick wall as it has to pump blood to this vessel: Incorrect.
  • Right atrium does NOT have a thick wall; it is a thin-walled chamber.
  • Right atrium receives blood from venae cavae, not pumps blood to pulmonary artery.
  • It is the right ventricle that pumps blood into the pulmonary artery, and it has a thick muscular wall.

Step 3: Identify the correct combination.
Statements (i), (ii), and (iii) are correct. Statement (iv) is incorrect. Therefore, the correct option is (i), (ii) and (iii). Final Answer: (D) (i), (ii) and (iii)