Structure and function of kidney

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The study and awareness of structure and function of kidney is very important for everybody because kidney play very important role in all the activities of human body. If kidney is working properly no doubt the person will be healthy and if there is any disease or any problem then this may cause to death because if kidney are damaged or not working properly, other organs are also affected. So, in order to keep your kidneys safe from any disease you must aware of the structure and function of kidney. In this article we will tell you all about the structure and function of kidney.

You must study the excretory system of human body if you want to know the structure and function of kidney.

Excretory System

Cells produce nitrogenous materials, salts and carbon dioxide as by-products of metabolic bread down of sugar, fats and proteins. If these toxic wastes accumulate in the body, they may cause damages. The process of removing the waste products from the body is called excretion. The organ system responsible for this excretion is known as excretory system. The excretory system removes non-solid wastes through sweat, urine and exhalation.

The human excretory system consists of one pair of kidneys and associated structure, i.e. a urethra, a urinary bladder and two ureters.

Human kidney

The human body has two kidneys in the abdominal region, one on either side of the vertebral column and its shape is like a dark brown bean. The outer surface of kidneys is convex while the inner surface is concave.

Human excretory system Internal structure of kidney

The tube, which arises from each kidney and enters the urinary bladder, is called a ureter. It moves urine from the kidneys to the bladder. Urinary bladder is a muscular sac, which collects urine from both kidneys through ureters. From the urinary bladder the urine is released outside the body through a fine tube is called urethra.

Internal structure of kidney

Internally, each kidney is divided into three region i.e. renal cortex renal medulla and renal pelvis. Renal cortex is the outermost region. Renal Medulla is the middle region and Renal pelvis is the inner area where urine is drained. The urine from renal pelvis flows into ureter.


Nephrons are the structure and functional units of kidneys. Each kidney has over one million nephrons. Each nephron has two parts. I.e. renal corpuscle and renal tubules.

Renal Corpuscle is called the first part of nephrons. It consists of two structures i.e. Glomerulus and Bowman’s capsule. Glomerulus is a cluster of blood capillaries formed by the division and sub division of small arteries. Bowman’s capsule is a cup shaped structure, enclosing the glomerulus. The tube like structure of the nephrons connected to the Bowman’s capsule at its tip is called the Renal Tubule. Urine is formed in these tubules. The renal tubule consists of three parts. Proximal tubules are called the first coiled part of the renal tubule. Loop and Henle is the next part and is made in U-shaped. The third and last part of the renal tubule is again coiled and is called distal tubule. Many nephrons’ distal tubules open in a collecting duct. Many collecting ducts join and drain the urine out of the nephrons into the Renal pelvis.

Internal structure of nephron and kidney


Role of kidney

Incoming blood arteries called arterioles transport blood to the kidneys that is transporting nitrogenous waste products from the body. Blood that contains nitrogenous waste travels to the Glomerulus inside the kidneys. Here most of the excess water and waste materials filtered from the blood into the Bowman’s capsule. The blood after losing waste material goes into the outgoing arteriole, which ultimately with many other arterioles forms the renal artery. The primary circulatory system receives the clean blood.

Through the Bowman’s capsule, waste and surplus water enter the renal tubule. From here, waste and surplus water travel through the proximal tubule, the Henle loop, and then through the distal tubule into the collecting duct as urine. The renal pelvis, which opens into each kidney’s ureter, receives the urine after it has been drained from the collecting tubules. Urine is transferred to the urinary bladder from the ureter. From here the urethra allows the urine to exit the body.

Structure of Bowmans capsule

Malfunctioning of kidney  

The most important thing to remember about kidney disorders is that kidney is not a solitary organ. When your kidneys are damaged or not working properly, other organs are also affected.

Formation of stones kidney

Sometimes kidneys do not work efficiently i.e. they cannot remove nitrogenous waste or salts from the blood properly. In such circumstances, the salts build up in the kidneys and create stones. Formation of stones disturbs the normal functioning of the kidneys and cause severe pain. Kidney stones can travel up the ureter or urethra. The excessive amounts of calcium salts in meals and uric acid, among other things, are major causes of kidney stones.

Stones in kidney and urinary bladder

Renal failure

The complete or partial kidney failure is referred to as renal failure. Long-term infections, diabetes, and hypertension are the leading causes of renal failure. Diabetes mellitus is a disease in which sugar level of the blood remains high. Hypertension is a state of high blood pressure of the body. Renal failure may also be caused by a sudden blockage of the blood flow to the kidneys. Dialysis and kidney transplant are the treatment for renal failure.

Treatment of malfunctioned kidneys

Removal of kidney stones

The small size stones can remove easily through the urinary system by drinking more water. Medium size stones are removed by lithotripsy, which involves bombardment of shock waves on the stones from the outside. Shock waves break the stones into small pieces, which are passed out of the body through urine. The large size stones still required surgery for their removal.


Dialysis, which is carried out by a device called a dialyzer, is the artificial cleaning of blood. The patient’s blood is run through a dialyzer filled with dialysis fluid. Blood flows through the tubes of the dialyzer and the dialysis fluid flowing around these tubes remove the waste materials from the blood. The body receives its cleaned blood back.

Dialysis process

Kidney transplant In this procedure, a healthy person’s kidney is grafted into the patient’s body to replace the damaged kidney. The donor of kidney may be a blood relative or any other close relative having the same blood group.

Transplanted kidney

Added by: Sadiq Ameen

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