MHT CET Medical202626 April 2026Morning ShiftBiologyBreathing and Exchange of GasesActual
Select the INCORRECT statement.
Options
- AThe _ pp CO ₂ of blood in pulmonary capillaries is 40 mm Hg before oxygenation.
- BThe _ pp CO ₂ of blood entering the pulmonary capillaries is 45 mm Hg.
- COxyhaemoglobin decreases the pH of blood.
- DIncrease in _ pp CO ₂ of blood and decrease in pH of blood allows HbO ₂ to dissociate, and release O ₂ in tiss
Correct answer
A. The _ pp CO ₂ of blood in pulmonary capillaries is 40 mm Hg before oxygenation.
Step-by-step solution
Blood entering the pulmonary capillaries is deoxygenated blood returning from the systemic circulation. The partial pressure of carbon dioxide ( p CO ₂ ) in this deoxygenated blood is 45 mm Hg . After gas exchange in the alveoli, the oxygenated blood leaves with a p CO ₂ of 40 mm Hg . Thus, before oxygenation, the p CO ₂ in the pulmonary capillaries is 45 mm Hg . This makes statement (1) incorrect and statement (2) correct. Oxyhaemoglobin is a stronger acid than deoxyhaemoglobin. The formation of oxyhaemoglobin rel