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

2024
Views:

106

Pages:

5
Author:

Sheha A.

Acid and Base Acids are defined as proton donors and bases as proton acceptors (Bronsted). Strong acids (e.g., HCl, H2SO4) dissociate completely even in acidic solution and weak acids (e.g., acetic acid) dissociate only partially in acidic solution. Strong bases (e.g., KOH, NaOH) dissociate completely and weak bases (e.g., Ca(OH)2) dissociate partially in alkaline solution. Many biochemical intermediates, including amino acids, are weak acids. Measurement of pH and Diagnostic Test: The pH of an aqueous solution can be approximately measured using various indicators like litmus, phenolphthalein, and phenol red, which undergo color change as a proton dissociates from the dye molecules. Accurate Measurement of pH in Clinical Laboratories Accurate measurement of pH is made with a glass electrode that is selectively sensitive to H+, K+, and other cations. In a pH meter, the signal from such an electrode is amplified and compared with the signal generated by a solution of actively known pH. Measurement of pH is most important because the catalytic activity of enzymes is strongly dependent on pH, and it may affect the structure and activity of biological molecules. Measurement of the pH of blood and urine are commonly used in medical diagnosis. Example: pH of blood plasma below the normal value of 7.4 is called acidosis (e.g., with severe uncontrolled diabetes) and above this value is called alkalosis. Acid-Base Balance The overall acid-base balance of the body is normally maintained by controlling the H+ concentration of the body fluids, especially ECF. The normal pH of systemic arterial blood is 7.35-7.45 Homeostasis of pH is maintained by: Buffer system via exhalation of carbon dioxide Kidney via secretion of H+ and reabsorption of HCO3-