Electrolytes An electrolyte in any chemical that dissociates to ions when dissolved in a solution. Ions can be positively charged (cations) or negatively charged (anions). The major electrolytes found in the body are sodium, potassium, calcium, magnesium, chloride, phosphate, sulphate and bicarbonate. The primary electrolytes of the ECF are sodium, chloride and bicarbonate and in […]

Fluid and electrolyte balance Regulation of fluid by the body is necessary to maintain homeostasis. If the water or electrolyte equilibrium is affected, many body functions fail to proceed at normal rates. Water Water is a major constituent of all living things. Most of the ions and molecules that make up living matter have chemical

Acid Base balance disturbances The pH of the ECF is determined by the rate of conju­gate base to their weak acids. The total amount of buffer base in whole blood including HCO3, Hb and other bases of lesser importance is called buffer base (B.B). These bases are known as metabolic components determining blood pH. Acid

Renal control of acid base balance The kidneys regulate acid-base balance by excreting either an acidic or basic urine. Excretion of either an acidic or a basic urine removes acids or basic from the ECF. Large numbers of HCO3– ions are filtered in the urine and if they are excreted into the urine, it removes base

Respiratory regulation of acid base balance The respiratory system acts as the second line of defense against acid base disturbances. An increase in PCO2 of ECF, decreases the pH, while a decrease in PCO2, increases the pH. Therefore, by adjusting the PCO2, the lungs effectively regulate the H+ ion concentration of the ECF. An increase in ventilation

Chemical acid base buffer systems When there is a change in the H+ ion concentration,  the body fluids react immediately to minimize the change. Chemical buffers act by converting either strong acids or bases into weaker acids or bases. The various chemical buffers are- Bicarbonate This is the most important buffer system in the body. Bicarbonate

Acid base balance The normal blood pH is 7.4. Maintenance of normal blood and extracellular pH within the narrow limits is essential for homeostasis. The pH usually refers to the hydrogen ion (H+)  concentration and has a widespread effect on the function of  the body systems. Any disturbance in the H+ ion concentration leads to imbalance of

Hormonal regulation of renal function ADH and water conservation ADH is synthesised in the cell bodies of hypothalamic nuclei (supraoptic nuclei) and transported to nerve fibre endings in the posterior lobe of the pituitary where it is stored in the secretory granules. Its release in the blood is controlled by osmoreceptors in the hypothalamus that

Excretion of dilute and concentrated urine Excretion of dilute urine When there is excess of water in the body and a reduction in plasma osmolarity, kidneys can excrete a dilute urine with a concentration as low as 50 mOsm/L. This can be achieved by reabsorbing only the solutes and not water in the distal parts

Counter current mechanism of kidney A counter current system of tubules or vessels exists where the inflow of fluid runs parallel to, counter to, and in close proximity to the outflow for some distance. These characteristics are common to the anatomical arrangements of the Loops of Henle and vasa recta. In the kidney, two counter