Nephron Definition

“Nephron is the standard functional unit of kidneys that is composed of a glomerulus and also its connected tubules through which the glomerular filtrate passes prior to it emerges as urine”

Let’s go through the framework and feature of the nephron and learn more in detail around the various components of the nephron and the duty of renal tubule in urine formation and excretion process.

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A nephron is the basic structural and useful unit of the kidney. They are the microscopic structure composed of a renal corpuscle and a renal tubule. The word nephron is acquired from the Greek word – nephros, definition kidney. There are about millions of nephrons in each human kidney.


Structure of Nephron

The mammalian nephron is a lengthy tube-favor structure, its length varying from 35–55 mm long. At one end, the tube is closed, folded and also expanded, into a double-walled, a cupfavor structure referred to as the Bowman’s capsule or renal corpuscular capsule, which encloses a cluster of microscopic blood vessels referred to as the glomerulus. This capsule and also glomerulus together constitute the renal corpuscle.

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The structure of nephron comprises two major portions:

Renal TubuleRenal Corpuscle

Renal Tubule

The renal tubule is a long and convoluted framework that emerges from the glomerulus and also deserve to be separated into three components based upon attribute.

The initially part is referred to as the proximal convoluted tubule (PCT) due to its proximity to the glomerulus; it continues to be in the renal cortex.The second component is called the loop of Henle, or nephritic loop bereason it creates a loop (through descfinishing and also ascending limbs) that goes with the renal medulla.The 3rd component of the renal tubule is referred to as the distal convoluted tubule (DCT) and this part is likewise restricted to the renal cortex.

The capillaries of the glomerulus are enclosed by a cup-like structure called Bowman’s capsule. This structure exoften tends to create highly coiled tubules called PCT. PCT proceeds to form the loop of Henle which ascends to DCT, which in turn opens up right into the collecting duct.

The major function of tubules is reabsorption and the procedure deserve to either be with active transport or passive deliver. In addition, secretions by tubules assist in the urine development without affecting the electrolyte balance of the body.

Proximal Convoluted Tubule (PCT)

The blood carried by the renal artery is filtered by the glomerulus and then passed to the PCT. Maximum reabsorption takes location in PCT of the nephron.PCT is the area of renal tubule wright here reabsorption of crucial substances choose glucose, proteins, amino acids, a significant portion of electrolytes and water takes place. The surface location for reabsorption is assisted in by the lining of the simple cuboidal epithelium in them. Reabsorption takes location at the cost of power, i.e., the procedure is energetic.PCT selectively secretes ions such as hydrogen, ammonia, and potassium into the filtrate and also absorbs HCO3–from it. Thus, PCT maintains the electrolyte and acid-base balance of the body fluids.

Henle’s Loop

Henle’s loop has actually a descending and an ascending limb. Being parts of the exact same loop, both the descending and also ascending limbs display different permecapacity. The descending limb is permeable to water but impermeable to an electrolyte, while the ascfinishing limb is permeable to electrolytes however impermeable to water. Due to the fact that the electrolytes acquire reabsorbed at the ascending loop of Henle, the filtprice gets diluted as it moves in the direction of the ascending limb. But reabsorption is restricted in this segment.

Distal Convoluted Tubule (DCT)

The DCT, which is the last part of the nephron, connects and also empties its contents right into collecting ducts that line the medullary pyramids. The collecting ducts amass contents from multiple nephrons and also fusage together as they enter the papillae of the renal medulla.

Comparable to PCT, DCT additionally secretes ions such as hydrogen, potassium, and NH3 right into the filtrate while retaking in the HCO3–from the filtrate. Conditional reabsorption of sodium ions and also water takes location in DCT. Therefore, it maintains the pH and also sodium-potassium level in the blood cells.

Collecting Duct

Collecting duct is a lengthy, directly tube wright here H+ and also K+ ions are secreted to maintain the electrolyte balance of the blood. This is additionally the area wbelow the maximum reabsorption of water takes area to produce focused urine.

Renal Corpuscle

The renal corpuscle consists of a glomerulus surrounded by a Bowman’s capsule. The glomerulus arises from an afferent arteriole and also empties into an efferent arteriole. The smaller diameter of an efferent arteriole helps to preserve high blood press in the glomerulus.

The Bowman’s capsule is split into 3 layers:

Outer Parietal layer: It is comprised of epithelial cells with minute pores of diameter 12nm.Center Basement membrane: This layer is selectively permeable.Inner Visceral Layer: It is composed of large nucleated cells called podocytes which bear finger-favor projections referred to as podocel.

Also Read: Person Excretory System


Tright here are 2 kinds of nephron:

Cortical nephron

These are the nephrons current within the cortex. These are short and also consist of about 80% of the complete nephrons.

Juxtamedullary nephron

These have lengthy loops of Henle and extfinish into the medulla. These are about 20%.


The main attribute of nephron is removing all waste assets consisting of the solid wastes, and other excess water from the blood, converting blood into the urine, reabsorption, secretion, and excretion of countless substances.

As the blood passes with the glomerulus through high push, the little molecules are relocated right into the glomerular capsules and travel via a winding series of tubules.

The cell existing in each tube absorbs various molecules excluding the glucose, water, and also other beneficial molecules which are called as the ultrafiltprice. As the ultrafiltprice molecules travel down the tubules they become even more and also more hypertonic, which results in more amount of water to be extracted from the ultrafiltprice before it exits the nephrons.

The blood surrounding the nephron travels ago into the body through the renal blood vessels, which are totally free of toxins and also other excess substances. The acquired ultrafiltprice is urine, which travels down through the collecting duct to the bladder, wbelow it will certainly be stored and also released through the urethra.

Also Read: Urine Formation And Osmoregulation


Though excretion in people takes place through lungs, skin, liver, the kidneys are the primary organs of the humale excretory system. They are bean-shaped organs, which weigh between 150 to 170 gms and also their size varieties from 4 – 5 inches lengthy.

The kidneys are located in the retroperitoneal room in the abdominal cavity, simply listed below the rib cage and current in the opposite direction or facing each other on both the left and right side of the body. The ideal kidney is slightly smaller sized and reduced than the left kidney.

Contrasted to males, the total area, dimension and the weight of the kidneys are smaller sized in females. As such, both male and also female need to be careful in the time of their kidney transplantation.

 The major features of the kidneys are to:

Maintains the body’s pHReabsorption of nutrientsRegulates blood pressureExcretion of wastes from the bodyRemoval of excess liquid from the bodySecret hormones that assist in the production of red blood cell, acid regulation, and so on.

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The sensible unit of the kidney is the nephron. Each kidney is composed of countless nephron which plays a significant duty in the filtration and also purification of blood. The nephron is split into 2 parts, namely, the glomerulus and also the renal tubule and helps in the removal of excess waste from the body.

Also Read: Regulation Of Kidney Function

Learn more about Nephron, its structure, function, renal tubule, renal corpuscles and other connected topics at BYJU’S Biology