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Nephron

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NEPHRON ANATOMY

The nephron is comprised of various tubular or related structures. Included in its design and network is the proximal convoluted tubular, the distal convoluted tubular, the glomerular capsule, and the ascending and descending limbs of the nephron loop.

NEPHRON STRUCTURE

The glomerulus is encompassed by the glomular capsule, also known as the Bowman’s capsule. The renal corpuscle is created by the glomular capsule and the vital, associated glomerulus. These are both positioned within the kidney’s renal cortex. The inner visceral layer of epithelium of the glomular capsule adjoins the outer parietal layer as well as connects with the glomular capillaries. Within the capsular space, which refers to the space between between the parietal layer and the inner visceral layer, the glomular filtration product gathers. Fenestrae, which refers to the nearly microscopic pores of the glomerular epithelium, permits the transmission of the filtrate from the blood to collect in the glomerular capsule space. Blood cells, platelets, and nearly all the plasma proteins from the blood stream are unable to pass through the fenestrae.

Masses of unique cells known as podocytes line the inner layer of the glomerular capsule. The podocytes are equipped with numerous pedicles, which are cytoplasmic extensions. Interdigitated around the glomerular capillaries, the pedicles resemble the fingers of a clasped hand. Although the pedicles are adjacent to one another, there are slit pore-like channels to permit the filtered molecules through that need to get to the interior of the glomerular capsule. The filtrate which enters the glomerular capsule then flows into the lumen of the proximal convoluted tubule.

NEPHRON DIAGRAM

Nephron
Image: Nephron


Cuboidal cells create the single celled lining of the proximal convoluted tubule wall and are covered with millions of micro-villi. Micro-villi act to augment the surface area to assist in the process of re-absorption. The re-absorption process is vital in providing the necessary salt, water, and necessary molecules to the peritubular capillaries. The molecular necessities are delivered via the tubular cells after passing through the lumen.

NEPHRON FACTS

The renal cortex houses the proximal convoluted tubule, the glomerulus, and the glomerular capsule. The proximal convoluted tubule feeds the nephron loop, which is also known as the loop of Henle. The fluid then traverses to the renal medulla via the descending limb of the nephron loop and then relies on the ascending limb of the nephron loop to get back to the renal cortex. Once the fluid returns to the renal cortex, the ascending limb of the nephron loop recoils, and is then considered the distal convoluted tube. The proximal convoluted tube is longer than the distal convoluted tube and has additional micro-villi. This is the final terminating segment of the nephron, easily determined by the finalization of the tubular design into the collecting duct, also known as the papillary duct. Papillary ducts pass through the renal papillary and then empty into the minor calyx.
The minor calyx conjoins with other minor calyxes to create a major calyx. Fluid that makes it into the major calyxes has finally transformed into urine. Once the major calyx is ready to continue the flow of the urine, it enters the renal pelvis where it collects until it is ready to traverse into the ureters and leave the kidney altogether.

There are essentially two types of nephrons, each is determined by its location within the kidney as well as the length of their associated loop. The inner one third of the cortex houses the nephron’s glomulari. These have longer loops than the cortical nephrons and are called juxtamedullary nephrons.

The kidneys are supplied with the appropriate nerves via the renal plexus of the tenth, eleventh, and twelfth thoracic nerves. The necessary sympathetic stimulation of the renal plexus creates the vasomotor vascular network response within the kidney. This response is a necessary function in determining the appropriate pressure of the circulation of blood as it regulates and determines the diameter of the arterioles.
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