Acid-Base Balance

Definition

Acid-base balance is the physiological process that regulates the pH of the body's fluids, particularly the blood, to maintain a slightly alkaline state. This delicate balance is essential for the proper functioning of cells, tissues, and organs throughout the body.

5 Must Know Facts For Your Next Test

1. The normal pH range for arterial blood is between 7.35 and 7.45, which is slightly basic.
2. The kidneys and lungs work together to regulate acid-base balance by excreting or retaining acids and bases as needed.
3. Imbalances in acid-base status can lead to serious conditions such as acidosis (excess acidity) or alkalosis (excess basicity).
4. Buffers, such as the bicarbonate-carbonic acid system, help maintain a stable pH by neutralizing excess acids or bases.
5. Respiratory regulation of acid-base balance involves adjusting the rate and depth of breathing to control the levels of carbon dioxide (an acid) in the blood.

Review Questions

• Explain the role of the kidneys and lungs in maintaining acid-base balance.
  • The kidneys and lungs work together to regulate acid-base balance in the body. The kidneys filter the blood, reabsorbing bicarbonate (a base) and excreting excess acids, such as hydrogen ions, to help maintain a slightly alkaline pH. The lungs, on the other hand, control the levels of carbon dioxide (an acid) in the blood by adjusting the rate and depth of breathing. This respiratory regulation helps remove excess carbon dioxide and prevent the blood from becoming too acidic.
• Describe how the bicarbonate-carbonic acid system acts as a buffer to maintain pH homeostasis.
  • The bicarbonate-carbonic acid system is a crucial buffer in the body that helps maintain a stable pH. This system involves the reversible reaction between carbon dioxide (CO2), water (H2O), and bicarbonate (HCO3-) ions. When excess acid enters the body, the bicarbonate ions can neutralize the acid by converting it to carbonic acid (H2CO3), which then dissociates into CO2 and H2O. Conversely, when there is an excess of base, the system can produce more bicarbonate ions to neutralize the excess. This buffering action helps keep the blood pH within the narrow, slightly alkaline range required for proper physiological function.
• Analyze how imbalances in acid-base status can lead to serious health consequences, and discuss the role of respiratory regulation in restoring balance.
  • Imbalances in acid-base status can have severe health consequences. Acidosis, characterized by an excess of acid in the body, can lead to a variety of problems, including confusion, fatigue, and even coma. Conversely, alkalosis, an excess of base, can cause symptoms such as muscle spasms, confusion, and seizures. To restore balance, the body relies on respiratory regulation, which adjusts the rate and depth of breathing to control the levels of carbon dioxide (an acid) in the blood. For example, in response to acidosis, the body will increase the rate and depth of breathing to exhale more CO2, thereby reducing the acidity of the blood. Likewise, in alkalosis, the body will slow down breathing to retain more CO2 and restore the slightly alkaline pH. This respiratory regulation, combined with the kidneys' ability to excrete or retain acids and bases, is crucial for maintaining the delicate acid-base balance required for optimal physiological function.

Related terms

pH: A measure of the acidity or basicity of a solution, with a range from 0 (highly acidic) to 14 (highly basic), and a neutral pH of 7.

Buffers: Substances that help maintain a relatively stable pH by neutralizing excess acids or bases in the body.

Respiratory Regulation: The process by which the lungs adjust the rate and depth of breathing to help maintain proper acid-base balance.