Acid-base balance

Definition

Acid-base balance refers to the mechanisms the body uses to maintain a stable pH level in the blood and other fluids, which is essential for proper physiological function. This balance is crucial because even slight deviations from the normal pH range (7.35 to 7.45) can lead to significant health issues. The kidneys play a vital role in regulating acid-base balance by excreting hydrogen ions and reabsorbing bicarbonate from urine, influencing overall blood acidity.

5 Must Know Facts For Your Next Test

1. The kidneys help maintain acid-base balance by filtering blood, selectively excreting hydrogen ions, and reabsorbing bicarbonate.
2. Buffer systems, including bicarbonate and phosphate buffers, are present in the blood to quickly respond to changes in pH levels.
3. Respiratory function also contributes to acid-base balance; increased carbon dioxide levels can lead to respiratory acidosis.
4. Metabolic acidosis occurs when there is an excess of acid in the body due to conditions like kidney disease or uncontrolled diabetes.
5. The body's normal pH range of 7.35 to 7.45 is tightly regulated; any significant deviation can result in serious health problems like coma or cardiac arrest.

Review Questions

• How do the kidneys contribute to maintaining acid-base balance in the body?
  • The kidneys maintain acid-base balance by regulating the excretion of hydrogen ions and the reabsorption of bicarbonate during the filtration process. By selectively allowing these substances to enter or exit the bloodstream, the kidneys can influence blood pH levels directly. This means that when there is an excess of acid, the kidneys will excrete more hydrogen ions, while reabsorbing more bicarbonate to help neutralize acidity.
• Discuss the role of buffer systems in maintaining acid-base balance and how they interact with renal function.
  • Buffer systems, such as bicarbonate and phosphate buffers, play a critical role in quickly adjusting pH levels in response to acidosis or alkalosis. These buffers work alongside renal function by neutralizing excess acids or bases immediately. While buffers provide immediate responses to pH changes, the kidneys provide a more long-term regulation by adjusting the levels of bicarbonate and hydrogen ions over time, ensuring that the body's acid-base homeostasis is maintained effectively.
• Evaluate how disturbances in acid-base balance can affect overall health and discuss potential consequences.
  • Disturbances in acid-base balance can lead to serious health issues such as metabolic acidosis or alkalosis, each affecting cellular functions and organ systems differently. For instance, metabolic acidosis may arise from conditions like kidney failure or diabetic ketoacidosis, leading to symptoms such as fatigue, confusion, and even shock if untreated. In contrast, respiratory alkalosis may occur due to hyperventilation, which can cause muscle twitching and cardiac arrhythmias. Thus, maintaining a proper acid-base balance is essential for preventing systemic complications and ensuring overall physiological stability.

Related terms

pH: A measure of acidity or alkalinity of a solution, with lower values being more acidic and higher values more alkaline.

Bicarbonate: A key buffer in the blood that helps maintain acid-base balance by neutralizing excess acids.

Renal Tubules: Small structures in the kidneys where reabsorption of bicarbonate and secretion of hydrogen ions occur, playing a crucial role in regulating blood pH.