Renal System Physiology

Renal System Physiology: The renal system is composed of kidneys. Kidney’s perform the functions such as excretion of waste products from metabolic processes, regulation of constancy of blood fluids, constant blood pH and blood pressure maintenance, regulation of various blood chemicals etc.

Kidney Failure:




Renal disease is classified as primary diseases and secondary diseases depending on the fact that whether the affected part is internal to kidneys or external to kidneys. Renal or kidney failure results in little or no urine formation. Due to this toxic substances such as urea accumulate in body causing symptoms such as head ache, dizziness etc. In critical cases it may also lead to death. If the kidney is not functioning enough, kidney stones will be formed due to calcium deposits and it will cause kidney blockage. When kidney failure occurs, kidney transplantation may be undertaken. But it is much expensive method. So the peritoneal dialysis or hemodialysis is recommended, than kidney transplantation.

Dialysis is broadly classified into two types, peritoneal dialysis and hemodialysis

1. Peritoneal dialysis:

This is a type of dialysis which is performed under emergency condition. This type of dialysis is done by puncturing two needles through the abdominal (peritoneum) and washing out the peritoneal cavity with a saline solution. Hence it is called peritoneal dialysis. The saline solution flows through a semi-permeable membrane outside the body and hence toxic substances are thus removed.

2. Hemodialysis:

Hemodialysis is a process for take away the waste stuff such as potassium and urea from the blood when kidneys are in failure. The chemical substances are removed from the blood by passing it through tubes surrounded by semi-permeable membrane. It is done by puncturing two needles through artery and vein and circulating the patient’s blood through a coiled plastic tube. The coiled tube is immersed in a dialysate solution (solution containing salts of Ca, Mg, K, Na etc). The dialysed solution utilized is a pure solution of mineral ions. Sodium bicarbonate is mixed in a more concentration compared to plasma to exact blood acidity. A little quantity of glucose is too added to the dialysate. As told, hemodialysis contains diffusion of solutes a semi-permeable membrane. It uses counter current pass where the dialysate is passing in the opposite direction to blood flow. Fluid removal is attained by varying the hydrostatic pressure of the dialysate section reasoning free water and various melt solutes to go across the membrane along a produced pressure gradient. Toxins such as urea, uric acid gradually pass through plastic tube into dialysate solution. The semi-permeable membrane does not allow blood cells and large protein molecules.


Sreejith Hrishikesan

Sreejith Hrishikesan is a ME post graduate and has been worked as an Assistant Professor in Electronics Department in KMP College of Engineering, Ernakulam. For Assignments and Projects, Whatsapp on 8289838099.

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