The given figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its functions? [figure]
- A - Pulmonary vein - takes impure blood from body parts, pO2 = 60 mm Hg
- B - Pulmonary artery - takes blood from heart to lungs, pO2 = 90 mm Hg
- C - Vena cava - takes blood from body parts to right auricle, pCO2 = 45 mm Hg
- D - Dorsal aorta - takes blood from heart to body parts, pO2 = 95 mm Hg
Answer
(3) C - Vena cava - takes blood from body parts to right auricle, pCO2 = 45 mm Hg
Solution
In the figure, the upper loop is the pulmonary circulation and the lower loop is the systemic circulation.
D (carrying blood from the heart to the lungs) is the pulmonary artery and A (bringing blood from the lungs to the heart) is the pulmonary vein; A carries oxygenated blood, not impure blood.
B (carrying blood from the heart to the body parts) is the dorsal aorta, not the pulmonary artery.
C brings deoxygenated blood from the body parts to the right atrium (auricle); it is the vena cava.
As per NCERT, partial pressure of CO2 in deoxygenated blood = 45 mm Hg (and pO2 = 40 mm Hg).
Answer: (3)