Certified Cardiovascular Technician Practice Exam

What is the gas produced by cellular metabolism that accumulates in tissues?

1. Oxygen

2. Nitrogen

3. Carbon monoxide

4. Carbon dioxide

The correct answer is: Carbon dioxide

The gas produced by cellular metabolism that accumulates in tissues is carbon dioxide. During the process of cellular respiration, cells convert glucose and oxygen into energy, resulting in carbon dioxide as a byproduct. This carbon dioxide is then transported from the tissues to the bloodstream, where it is carried to the lungs to be exhaled. When metabolism occurs, especially in active tissues where energy demand is high, the production of carbon dioxide increases. If not adequately removed from tissues, it can accumulate, leading to increased acidity in the local environment. This accumulation can signal the body to increase respiration or alter blood flow to maintain homeostasis. In contrast, oxygen is consumed during metabolism, nitrogen is not a metabolic byproduct in this context, and carbon monoxide is generally not produced during cellular metabolism and is rather a harmful gas that can be produced by incomplete combustion of carbon-containing fuels.