University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

160

Pages:

5
Author:

Sheha A.

Regulation of Body pH by Kidney The kidneys play a significant role in the regulation of body pH. The primary function of the kidneys is to excrete acids. Mechanism: The kidneys regulate pH by excreting H+ ions and reabsorbing bicarbonate (HCO3-). The pH of the urine can vary from 4.5 to 8.0. The kidneys can excrete large amounts of acid in the form of titratable acid (e.g., phosphoric acid) and ammonium ions. This is possible by renal tubular secretion and reabsorption of bicarbonate and hydrogen ions. Kidneys cannot excrete Fixed acids like HCl, phosphoric acid, and sulfuric acid. These acids are eliminated by the lungs as CO2 and water. These acids are buffered by bicarbonate in the blood. The kidneys play a crucial role in maintaining the pH of the blood by regulating the excretion of bicarbonate and hydrogen ions. The kidneys can also regulate the reabsorption of bicarbonate in the distal tubules. When the excess acid production is compensated with increased excretion of H+, the pH is maintained. When acid is in excess, the kidneys excrete NH4+ which is an acidic cation. When alkali is in excess, the kidneys excrete HCO3- which is an alkaline anion. The kidneys can change the pH by manipulating the reabsorption of bicarbonate and the excretion of H+ ions. Renal tubular acidosis: This is a condition where the kidneys cannot properly excrete acid. This can lead to metabolic acidosis. Potassium: Potassium is a major intracellular cation. It is essential for maintaining the resting membrane potential of cells. The kidneys play a crucial role in regulating potassium balance. Hyperkalemia: This is a condition where the potassium level in the blood is too high. It can be caused by kidney failure, diabetes, and certain medications. Hypokalemia: This is a condition where the potassium level in the blood is too low. It can be caused by diuretics, vomiting, and diarrhea. There are 4 possibilities of acid-base disturbances: Metabolic Acidosis Metabolic Alkalosis Respiratory Acidosis Respiratory Alkalosis In both acidosis and alkalosis, the body tries to compensate for the abnormal pH by changing the HCO3-/H2CO3 ratio by changing the pulmonary elimination of CO2 or renal bicarbonate elimination. If it succeeds to compensate, the normal pH is restored. If it fails to compensate, the acidosis or alkalosis is said to be uncompensated.