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Red blood cells (RBCs) play a crucial role in the transport of carbon dioxide (CO鈧�) in the body. These cells contain a protein called hemoglobin, which is primarily known for carrying oxygen, but it also participates in transporting CO鈧�.

When CO鈧� enters the bloodstream, a portion of it diffuses into RBCs. Inside these cells, CO鈧� binds with hemoglobin to form carboaminohemoglobin. This process facilitates the transport of CO鈧� from the tissues back to the lungs, where it can be exhaled.

RBCs are highly efficient in handling gases, not only because of hemoglobin but also due to their flexible, biconcave shape. This unique form increases the surface area for gas exchange, making them indispensable in maintaining the body's physiological balance.

• CO鈧� binds with hemoglobin forming carboaminohemoglobin
• Efficient transport back to the lungs
• Vital for removing CO鈧� from the body

In addition to transportation by RBCs, carbon dioxide is also converted into bicarbonate ions in the blood. This transformation is an important aspect of maintaining acid-base balance in the body.

When CO鈧� reacts with water ( >H鈧侽) in the presence of the enzyme carbonic anhydrase, carbonic acid (H鈧侰O鈧�) is formed. This weak acid quickly dissociates into bicarbonate (HCO鈧冣伝) and hydrogen (H鈦�) ions. Most of the CO鈧� in the blood is carried in this way, as bicarbonate, which is highly soluble in plasma.

This bicarbonate mechanism not only helps in CO鈧� transport but also plays a key role in buffering the blood pH. By controlling the levels of bicarbonate, the body can regulate the acidity of the blood effectively.

• CO鈧� reacts with water forming carbonic acid
• Dissociates into bicarbonate (HCO鈧冣伝) and H鈦� ions
• Crucial for acid-base balance

The third method by which carbon dioxide is transported in the blood is through its dissolution in blood plasma. Although a smaller proportion compared to other methods, it is still significant for the process of gas exchange.

Dissolved CO鈧� in plasma accounts for about 5-7% of the total CO鈧� transported. This dissolved form can easily diffuse out of the blood into the alveoli in the lungs, where it is expelled from the body during exhalation.

The presence of dissolved CO鈧� in plasma contributes to maintaining a gradient that facilitates the movement of CO鈧� from tissues into the blood. This is essential, as it ensures a continuous removal of carbon dioxide from metabolically active tissues.

• Accounts for a smaller fraction of CO鈧� transport
• Important for maintaining CO鈧� gradients
• Essential for efficient gas exchange in lungs