Carbon dioxide

Definition

Carbon dioxide is a colorless, odorless gas that is a natural component of Earth's atmosphere and is produced by the respiration of animals and plants, as well as by combustion processes. It plays a crucial role in the process of gas exchange in living organisms, particularly in the respiratory system where it is exchanged for oxygen during respiration and is also involved in maintaining the acid-base balance in the body.

5 Must Know Facts For Your Next Test

1. Carbon dioxide is produced as a waste product during aerobic respiration, where glucose is broken down for energy.
2. In the lungs, carbon dioxide diffuses from the blood into the alveoli, where it is expelled from the body during exhalation.
3. The concentration of carbon dioxide in the blood influences the rate of breathing; higher levels can stimulate increased respiratory rates.
4. Carbon dioxide plays a key role in maintaining blood pH levels through its interaction with bicarbonate ions in a buffer system.
5. Excessive carbon dioxide levels can lead to respiratory acidosis, which occurs when the body cannot eliminate CO2 effectively, resulting in a decrease in blood pH.

Review Questions

• How does carbon dioxide function in the process of gas exchange within the lungs?
  • In the lungs, carbon dioxide is exchanged for oxygen during gas exchange. When blood flows through pulmonary capillaries surrounding the alveoli, carbon dioxide diffuses from the blood into the alveoli due to a higher concentration gradient. This allows oxygen to be taken up by red blood cells while carbon dioxide is expelled from the body when we exhale.
• What are the physiological effects of elevated carbon dioxide levels in the bloodstream?
  • Elevated carbon dioxide levels in the bloodstream can lead to increased respiratory rates as the body attempts to eliminate excess CO2. This condition can also result in respiratory acidosis, where increased CO2 lowers blood pH, potentially disrupting normal cellular functions and leading to symptoms like confusion, headache, and shortness of breath. If not corrected, severe acidosis can be life-threatening.
• Evaluate the role of carbon dioxide in maintaining acid-base balance within the human body and its implications for overall health.
  • Carbon dioxide plays a critical role in maintaining acid-base balance through its conversion to bicarbonate ions in a reversible reaction that helps buffer changes in pH. This balance is vital for normal physiological functions and overall health. Disruption of this balance due to high or low levels of carbon dioxide can lead to metabolic disturbances, impacting organ function and leading to conditions such as respiratory acidosis or alkalosis. Effective regulation of CO2 levels is essential for homeostasis.

Related terms

Oxygen:

A colorless, odorless gas essential for the respiration of aerobic organisms, which is taken up by the blood in the lungs and delivered to tissues.

Respiration:

The biochemical process by which cells convert glucose and oxygen into energy, producing carbon dioxide and water as byproducts.

Hematocrit: The proportion of blood volume that is occupied by red blood cells, which can influence the blood's capacity to transport oxygen and carbon dioxide.