H⁺ generated from CO₂ at the tissue level is A) the major source of hydrogen ion in the body B) normally buffered in transit between the tissues and the lungs by hemoglobin C) responsible for the fact that the pH of the venous blood is higher than the pH of the arterial blood D) the major source of hydrogen ion in the body and normally buffered in transit between the tissues and the lungs by hemoglobin E) all of these

Question

Quizplus · Accepted Answer

H⁺ is the chemical equation for the dissociation of carbonic acid (CO₂) in the presence of water. This process generates hydrogen ions (H+) which are potentially acidic. Therefore, choice A is correct as H⁺ is a major source of hydrogen ions in the body. However, these hydrogen ions are typically buffered in transit between tissues and lungs by hemoglobin, meaning that hemoglobin acts as a sponge to absorb and release these hydrogen ions as needed to maintain pH balance in the blood. Choice B is therefore also correct. The pH of venous blood (blood returning to the heart) is typically more acidic than arterial blood (blood flowing away from the heart). This is due in part to the generation of hydrogen ions from the breakdown of carbonic acid, but also because tissues produce other acidic waste products. However, the buffering capacity of hemoglobin helps to keep the pH of both venous and arterial blood within a relatively narrow range. Choice C is therefore incorrect. Overall, choice D is the best answer because it accurately captures both the major role of H⁺ as a source of hydrogen ions and the important buffering function of hemoglobin. Choice E is incorrect because it includes the incorrect statement in choice C.

H+ Generated from CO2 at the Tissue Level Is

H⁺ Generated from CO₂ at the Tissue Level Is