KIDNEYS

We have two kidneys. Kidneys are located on either side of spine at the lower level of rib cage. In appearance they resemble kidney bean and are about the size of the human fist (about 10 cms. long). Each kidney weighs about 120 - 180 gms. Sometimes a person is born with one kidney but still can live normal life.

Internal structure of the kidney

The kidney consists approximately one million functioning units called NEPHRONS. Each Nephron has the same structure and function . Thus the work of the kidneys may be considered be the sum total function of all the Nephrons put together. A Nephron consist of a tuft of tiny blood vessels called a Glomerulus and a long microscopic tube called Tubule. This tubule winds through the kidney substance until it lends into a common sac called the kidney pelvis, (upper part of ureter) located on the hollow side of the kidney. A much larger Ureters connects the kidney pelvis with bladder. Each kidney has a renal artery a renal vein. We need about 5,00,000 Nephrons to maintain 'normal' renal function. Thus one kidney would be sufficient for normal life. IMPURE BLOOD enters the kidney via renal artery and passes into the Nephrons where excess fluid and waste products are removed. The filtered (or cleaned) blood than leaves the Nephrons and exist via the renal vein. Kidneys receive about 1200 ml., 20% of total blood volume per minute, inspite of it's small size indicating it's important role. Large amount of fluid is filtered through Glomeruli (normal functioning unit). About 120 ml. Per Minute ( 99% ) of this fluid is reabsorbed or modified as per body's requirements in tubules. The excess fluid and waste product (URINE) enter the ureter and pass into the bladder (on average 1 ml of urine is produced per minute). Where they are extracted as urine. The entire process is repeated 24 hours a day, 7 days / week (so that body's total blood supply is constantly being filtered).

       
Internal Structure Of The Kidney

Food ingested by us (protein, carbohydrate and fat) is metabolized to produce energy with the help of oxygen which we breath. With metabolism waste products are generated (liquid, solid and gaseous). Gaseous products are removed through lungs. Solid through intestine. While liquid waste products are removed mainly through kidneys.

Function of the Kidney

1. It cleans the blood about 500 to 600 gallons per day by removing excess of waste which consist of urea, creatinine, potassium, salt phosphorus etc.
2. It maintains the salt & water composition of total body fluids by removing excess fluid with waste called URINE.
3. It maintains the acid base balance of the body.
4. It controls the normal Blood Pressure through production of liberated Hormones called ANGIOTENSINOGEN.
5. It controls the normal haemoglobin by producing hormone called ERYTHROPOIETIN. Erythropoietin controls the rate of red blood cells made by the bone marrow.
6. It helps in proper calcium metabolism by activating Vitamin D. (Vitamin D helps in proper calcium metabolism).

One will hear following words in kidney disease.

NEPHROLOGIST

A medical physician who specializes in the medical treatment of urinary system diseases (kidneys, ureters, bladder urethra and stones in urinary tract ). Nephorologist will also guide & take care for dialysis, planning of kidney transplantation and post transplantation care and follow up.

UROLOGIST

A surgeon who specializes in surgical treatment of urinary systems (kidneys, ureters, bladder, urethra) removal of stones in urinary tract. He also take care of surgical part of kidney transplantation & prostate gland.

BLOOD UREA ( BUN ) :

It is waste product of protein metabolism. Normal range is 7 - 21 mg/dl.

CREATININE :

It is end product of muscle metabolism. Normal range is 0.5 to 1.5 mg/dl.

DIALYSIS:

Artificial treatment of cleaning the blood (removal of waste products and excess of water).

Contents Of Urine : 95% ----- Excess of water 02% ----- Urea 01% ----- Sodium Chloride 02% ----- Creatinine, Uric acid salts, potassium, magnesium, calcium & ammonia pigments 100%----- Total