The human kidney comprises a million nephrons- the filtering units of this complex and highly vascular organ. Each Nephron is made up of highly coiled tubules, one end of which is designed in the form of a cup-shaped structure. Inside this cup, there is a network around the wall that has a tuft of capillaries called the glomerulus, with a special fenestrated basement membrane.
Each glomerulus filters out water and solutes from the blood passing through it into the surrounding space and is the cavity between the two walls of the cup. The next part of the tubule is coiled and looks in the form of a U-shaped loop carrying the filtered fluid deep down into the medulla. This part of the Nephron is called the Loop of Henle.
The loop of Henle function is to reabsorb water and sodium chloride from the filtrate. This conserves water for the organism, resulting in highly concentrated urine. In other words, the Loop of Henle is a heterogeneous segment that comprises the pars recta of the proximal tubule, the thin descending and ascending limbs along the medullary and cortical thick.
Species that live in arid environments such as deserts carry highly efficient loops of Henle. In the anatomy area, the loop of Henle is divided into three different sections- thin descending limb, thin ascending limb and thick ascending limb.
The first portion of the loop is the thin descending limb which is permeable to water. The descending loop of Henle is an important function. The liquid that reaches the bend of the loop is richer in salt and urea than the blood plasma. As the liquid returns through the thin ascending limb, sodium chloride diffuses out of the tubule into the surrounding tissue.
In the third segment of the loop, the thick ascending limb, affects further removal of salt, against the concentration gradient.
There is net potassium reabsorption in the loop Henle. The procedure to transport potassium in Henle's loop is quite complex. Here the potassium is concentrated in the fluid passing through the descending loop of Henle to such an extent that the concentration in the fluid at the papilla is ten times higher than plasma.
The Function of the Loop of Henle
The absorption of water within the descending limb leads to an increasing osmotic gradient within the tubule. The loop of Henle is supplied by two vasa recta which straight vessels closely accompany the tubule’s hairpin- are shaped course. These vessels carry blood in the opposite direction, similar to the tubular fluid- the countercurrent mechanism. These result in water absorbed on one hand, and solute on the other.
It is also called the countercurrent multiple systems, responsible for maintaining osmotic medullary gradient in the outer medullary tissue. The thick descending limb of the loop of Henle expresses a sodium-potassium-chloride cotransporter and helps reabsorb approximately a third of the filtered sodium and chloride from the fluid in the tubular lumen into the blood.
Some of the Loops of Henle Functions are-
Homeostatic mechanisms to regulate extracellular fluid volume
Regulating potassium, calcium and magnesium excretion at the lowest energy costs
Regulating composition of the urinary protein
Role of Ascending Loop of Henle is -
The ascending loop of Henle function is impermeable to water. In this, sodium chloride is transported from a thick portion of the ascending limb without accompanying water so an osmotic gradient of approximately 200 mosm/kg is generated. Active sodium transport is accomplished by Na+, K+ -ATPase located in the basolateral membranes of the tubular cells.
Role of the Descending Loop of Henle Function
The descending limb is highly permeable to water and the reabsorption occurs via AQPI channels. During this process, low amounts of urea Na+ and other ions are reabsorbed.
Functions of Nephron
The primary function of Nephron is to flush out waste products which include solid waste and other excess from the blood. This blood is converted into urine, secretion and excretion.
Nephron, which is a basic structural unit of the kidney, is in the form of a microscopic structure composed of a renal corpuscle and renal tubule.
The cell present in each tube absorbs different molecules, excluding glucose and beneficial molecules. The blood surrounding the Nephron travels back to the body through renal blood vessels free from toxins.