What is the function of the Renal Cortex?

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The kidneys are the excretory organs which help purify the blood and remove toxins from the body. They are placed behind the abdominal cavity. The kidneys are the filtration systems and help in the everyday functioning of urinary system and are the prime organs involved in the sustenance of fluid homeostasis. Each kidney is broadly divided into an external part called as renal cortex and an internal part termed as medulla. The main function of a renal cortex is to filter blood and remove unwanted substances out of the body. This task is accomplished with the help of nephrons and glomeruli that are housed in the renal cortex.


What is the renal cortex?

The renal cortex is the outer smooth, continuous layer of the kidney. The process of ultra filtration of blood is carried out in the renal cortexwhich is also known as high pressure filtration or the ultra filtration. Renal cortex is the external, outermost part of kidney and the filtration process is termed so, as this filtration can only be completed when the blood coming into the kidney through the renal artery is already carrying high pressure. Cortex consititues glomeruli in billions which are small tiny ball shaped capillaries. Every glomerulus is encircled by Bowman’s capsule. Glomeruli leak occurs in cortex during which the different components like white blood cells, red blood cells, platelets, fibrinogen staying in the blood vessels are leaked into Bowman’s capsule. The amount of this leakage is around 160 liters in every 24 hours. The liquid that is termed as ultra filtrate is mostly reabsorbed into the medulla and sent back to the blood.


How does the ultra filtration in renal cortex work?

The renal cortex is the kidney’s external section and comprise of medulla pyramids that filters around 43 gallons of water every day via nephrons which are small structures present in millions inside these pyramids. Every group of 10000 nephrons constitute small vessel clusters termed as glomerulus capillaries. These capillaries with the help of pressure force the blood into the double walled filtration membrane termed as Bowman’s capsule. Through this capsule along with water from blood plasma, salt, urea and glucose too are filtered out. Renal cortex comprise of distal and proximal convoluted tubules. From the proximal convoluted tubules this filtration process flows and continues the process of re-filtration of usable glucose into the blood flow. Unabsorbed glucose goes into urine and is a harbinger of diabetes as well as kidney disorders. The distal convoluted tubules present in the cortex help absorb salt back into the blood stream. Loop of Henlé, a part of medulla reabsorbs water and filters it into a collecting duct that also generates urine. This process of tubular reabsorbtion is carried out depending upon the body condition.


What are  functions of the renal cortex?

Renal cortex performs some very important functions as a part of kidney:

  • The glomoeruli present inside the renal cortex, filters plasma fluids
  • With the help of inter pyramidal extensions, the renal cortex penetrates in between the two kidneys which are termed as renal columns, thereby acting as support for blood vessels
  • Renal cortex actively takes participation in kidney metabolism by creating ammonia for titrating urine acidity and thus help in acid-base regulation
  • Cortex is highly involved in the regulation of metabolic wastes like uric acid, urea and creatinine’
  • It also aids in the excretion of diluted or concentrated urine which is very important for maintaining volume of blood


What is the difference between the cortex and medulla of kidney?

Renal cortex and medulla are the two very important and major parts of kidney but both of them differ in their texture. This differentiation is very prominent at many places where the nephrons are disposed. The renal cortex constitutes convoluted tubules along with renal corpuscles whereas loops of Henle and collecting ducts are important portions of medulla. The medulla is further divided into stripes or zones which are grossly visible and hence look different from the renal cortex in texture. Also the medulla constitutes interstitial environment which is not prominent in cortex. One of the major similarities between both the medulla and renal cortex is that both these kidney organs are made up of millions of separate nephrons that are packed as one.


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