NEET PG DENTAL EXAM

Detailed explanation-1: -Answer and Explanation: The correct answer: The site of actual oxygen and carbon dioxide exchange in the lungs is at the a) alveoli. The alveoli are the structure present at the lower part of the respiratory system and that is where the exchange of gases takes place.

Detailed explanation-2: -Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.

Detailed explanation-3: -The respiratory system works with the circulatory system to provide this oxygen and to remove the waste products of metabolism. It also helps to regulate pH of the blood. Respiration is the sequence of events that results in the exchange of oxygen and carbon dioxide between the atmosphere and the body cells.

Detailed explanation-4: -Earthworms exchange oxygen and carbon dioxide directly through their skin. The oxygen diffuses into tiny blood vessels in the skin surface, where it combines with the red pigment hemoglobin. Hemoglobin binds loosely to oxygen and carries it through the animal’s bloodstream.