The kidneys contribute to homeostasis more extensively than any other single organ. They regulate the electrolyte composition, volume, osmolarity, and pH of the internal environment and eliminate all the waste products of bodily metabolism except for respiration-removed CO2. They accomplish these regulatory functions by eliminating in the urine substances the body doesn’t need, such as metabolic wastes and excess quantities of ingested salt or water, while conserving useful substances. The kidneys can maintain the plasma constituents they regulate within the narrow range compatible with life, despite wide variations in intake and losses of these substances through other avenues. Illustrating the magnitude of the kidneys’ task, about a quarter of the blood pumped into the systemic circulation goes to the kidneys to be adjusted and purified, with only three quarters of the blood being used to supply all the other tissues.

Homeostasis depends on maintaining a balance between the input and the output of all constituents in the internal fluid environment. Regulation of fluid balance involves two separate components: control of extracellular fluid (ECF) volume, of which circulating plasma volume is a part, and control of ECF osmolarity (solute concentration). The kidneys control ECF volume by maintaining salt balance and control ECF osmolarity by maintaining water balance. The kidneys maintain this balance by adjusting the output of salt and water in the urine as needed to compensate for variable input and abnormal losses of these constituents. Similarly, the kidneys help maintain acid–base balance by adjusting the urinary output of hydrogen ion (acid) and bicarbonate ion (base) as needed. Also contributing to acid–base balance are the buffer systems in the body fluids, which chemically compensate for changes in hydrogen ion concentration, and the lungs, which can adjust the rate at which they excrete hydrogen ion–generating CO2.

At the end of the course,students will earn about

1. The Body Fluid Compartments: Extracellular and Intracellular Fluids; Edema

2. Functional Anatomy of the Urinory System and Urine Formation by the Kidneys

3. Glomerular Filtration, Renal Blood Flow, and Their Control

4. Renal Tubular Reabsorption

5. Renal Tubular Secretion

6. Urine Concentration and Dilution; Regulation of Extracellular Fluid Osmolarity and Sodium Concentration

7. Renal Regulation of Potassium, Calcium, Phosphate, and Magnesium; Integration of Renal Mechanisms for Control of Blood Volume and Extracellular Fluid Volume

8. Acid-Base Regulation, Renal Mechanisms

9. Diuretics, Kidney Diseases

The following Books are recommended for this course;

TEXTBOOK OF MEDICAL PHYSIOLOGY, GUYTON,A.C, 11TH Edition

REVIEW OF MEDICAL PHYSIOLOGY ,GANONG,W.F, 22ND Edition

PHYSIOLOGY BOARD REVIEW SERIES, COSTANZO, LINDA S,6TH Edition

ESSENTIALS OF MEDICAL PHYSIOLOGY, SEMBULINGHAM,K, 7TH Edition

 Assessment Criteria:

Assessment schedule: 5 tests & one send-up written examination including objective & subjective (SEQs, LEQs) type questions
Internal Assessment (based on class tests, class performance and attendance): 20 Marks
Written: 80 Marks