There are two kidneys in the human body. Kidney is responsible for filtration of blood approximately 180 litres of blood daily. During this filtration process from blood, it removes the metabolic waste, excess water, excess electrolytes, and form waste products as urine.
This all functions are carried out by the nephron, a small structural and functional unit of the kidney. It is responsible for actual filtration process. Each kidney has millions of nephrons which carried out filtration process throughout life.
The kidney has approximately 1 million nephrons. Each nephron work independently to filter out the blood. Due to the nephron, body is remained healthy as body waste products get excreted properly.
Functions of the Nephron
Nephron primary function is to filter out the waste products form in the nephron. Other functions of nephrons are,
- To remove the metabolic waste products form in the blood
- To reabsorb the essential nutrients from getting wast through urine
- Reabsorb water and electrolyte level as maintaining homeostasis
- Maintain blood pH level
- Nephron also helps to regulate blood pressure (causing release of more water and sodium in case of high blood pressure)
- To excrete waste products and form urine
Location of Nephron
Nephron is located in the renal cortex and renal medulla of the kidneys.
Renal cortex is the outer part of the kidney. Most of the nephrons are present here. The filtration process of nephron is start here. The nephron present in this are are called as cortical nephrons. They contribute to 85% of all the nephrons. This nephrons generally responsible for the blood filtration.
In renal medulla, loop of henle and collecting ducts are there. This consitute the middle part of the nephron. It is where the urine gets concentrated, as most of the nutrients are remove from filtrate leads to forming a concentrated urine. The nephron in the renal medulla are called as juxtamedullary nephrons. They mak up of 15% of all the nephrons. This type of nephron especially important for preserving essential body fluid during dehydration.
Structure of Nephron
Each nephrons is consist of two main parts, renal corpuscle and renal tubule.
Renal corpuscle
Renal corpuscle consist of glomerulus and bowmans capsule.
Glomerulus recieved blood via afferent arteriole. This glomerulus has pressure difference as the pressure at which the blood comes in and goes out. This difference allows the water and small dissoloved substances to filter out the blood.
Bowmans capsule is layer covered the glomerulus. It covered the entired glomerulus look like a cup shaped in structure.
This glomerulus and bowmans capsule make up the renal corpuscles where the formation of urine starts.
Renal tubule
After filtration in the renal corpuscle, the filtrate material enters into the renal tubule. Renal tubule consist of PCT, loop of henle and DCT.
Proximal convoluted tubule
Proximal convoluted tubule is the initial version of the PCT. In this part, majority of the reabsorption of fluid take place.
Loop of Henle
Loop of henle is of asending and descending loop of henle. Descending limb of loop of henle is highly permeable for the water. Ascending limb of loop of henle is imperable to water. It is mostly responsible for the transport of sodium and chloride.
Distal Convoluted Tubule
Distal convoluted tubule reabsorb most of sodium, calcium and potassium, hydrogen ions. They were serve as last stage reabsorption of the electrololyte.
Collecting duct
Collecting duct is where the urine is recieved from the multiple nephrons. It is final storage house of urine before urination.
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