Name: Kidney Transplantation
Uploaded: 2019-07-19
Duration: 5 min 31 s
Description: A kidney transplant is a surgical procedure to place a healthy kidney from a living or deceased donor into a person whose kidneys no longer functioning prope...

Question

Give an account of the structure and functions of the human kidney.

Accepted Answer

The excretion system plays an essential role in the removal of harmful and toxic substances from the body of an individual. The most Important excretory organs in the urinary system where urine formation takes place and through the urine about 75% excretory products are eliminated from the body are called Kidney. The kidneys are paired excretory organs which produce urine. The kidneys are situated on the posterior abdominal. All behind the peritoneum on either side of the vertebral column of the level of the 12th thoracic and 1st or 2nd lumbar vertebrae.

External structure—Kidneys are smooth surfaced and dark brownish-red in color. Each kidney measures about II cm in length, 6 cm in breadth, and 3 cm. in thickness. In the adult, it weighs about 125-170 gm. Each kidney has the upper and the lower poles (ends), the lateral and the medial margins, and the anterior and posterior surfaces. The lateral margin is convex, while the medial margin has a concavity in the middle. It is called the hilum of the kidney (hilus renalis) through which renal artery and nerves enter the kidney and renal vein and ureter leave through it. The kidneys are invested by the fibrous capsule.

Internal structure of kidney— Each kidney is composed of a large cavity, called the renal sinus which contains the renal pelvis. Around the renal pelvis, the medulla, and then superficially the cortex are present. The renal pelvis breaks up into 2 or 3 main divisions known as greater or major calyces. Each major calyx further breaks up into 8 cup-shaped lesser or minor calyces which. terminating into renal papillae.
In the kidney, the reddish-brown cortex occupies the peripheral part around the medulla. It is about 4 mm thick. The medulla is formed by the number of striated conical structures called renal pyramids. The wide bases of the pyramids face at the surface of the kidney and the apices are directed towards the sinus. Two or more apices join to form rounded eminences termed renal papillae. There are about a total of 12 papillae are present on average. Each papilla has a small opening called foramina through which urine is discharged into calyces. The cortical part that penetrates between the pyramids is known as renal columns. The pyramids appear striated because the urinary tubules (renal tubules) and the blood vessels are arranged in them in a straight direction. The presence of pyramids reflects the lobular structure of the kidney. Each kidney is made up of about one million excretory units called nephrons.

Functions of kidneys:

Kidneys eliminate about 70% of toxic and metabolic waste products from the body through the urine.

It maintains water and salt balances of the body and acid-base balance of the body.

It manufactures certain substances like renin. ammonia, hippuric acid, and inorganic phosphate.

It regulates the relation of osmotic pressure between blood and tissue.

Kidney synthesizes erythropoietin. It is a glycoprotein that helps for the RBC formation in the bone marrow.

Give an account of the structure and functions of the human kidney.

Important Questions on Excretory Products and Their Elimination

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