Nephron: Functions of Nephron, Primary Functions, Proximal Tubule

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Functions of Nephron

The Primary Function

  • To remove all waste products including the solid wastes, and other excess water from the blood.

  • To convert blood into the urine, reabsorption, secretion, and excretion of numerous substances.

  • The small molecules are moved into the glomerular capsules as the blood passes through the glomerulus with high pressure.

Proximal Tubule

  • It is a part of the nephron that can be divided into an initial convoluted portion and a following straight (descending) portion.

  • Into the peritubular capillaries, fluid in the filtrate entering the proximal convoluted tubule is reabsorbed.

  • This also includes more than half of the filtered salt and water along with filtered organic solutes (primarily glucose and amino acids).

Loop of Henle

  • It is a U-shaped tube that extends from the proximal tubule.

  • It also consists of a descending limb and an ascending limb.

  • It begins in the cortex, receiving filtrate from the proximal convoluted tubule.

    • Extends into the medulla as the descending limb.

    • Returns to the cortex as the ascending limb to empty into the distal convoluted tubule.

Distal Convoluted Tubule

  • For active transport to take place, cells lining the tubule have numerous mitochondria to produce enough energy (ATP).

  • The endocrine system is responsible for regulating much of the ion transport taking place in the distal convoluted tubule.

  • The distal convoluted tubule reabsorbs more calcium and secretes more phosphate.

Connecting Tubule

It is the final segment of the tubule before it enters the collecting duct system.

Juxtaglomerular Apparatus

  • It is a specialized region associated with the nephron.

  • It produces and secretes into the circulation the enzyme renin (angiotensinogenase).

  • The JGA is located between the thick ascending limb and the afferent arteriole.

  • The three components are the macula densa, juxtaglomerular cells, and extraglomerular mesangial cells.

Major Functions of the Kidney

  • It helps in the reabsorption of nutrients.

  • It also helps in regulating blood pressure.

  • Excretion of wastes from the body.

  • Removing excess fluid from the body.

  • Also helps in secreting hormones that help in the production of red blood cell, acid regulation, etc.

FAQs

Q 1. What are the two main parts of a nephron structure?

Answer:

The two main parts of a nephron structure are:

i) Renal tubule

ii) Renal corpuscle

Q 2. What’s the main function of a nephron?

Answer:

The main functions of a nephron are:

i) A nephron regulates the concentration of water and minerals such as sodium by filtering the blood and reabsorbing the important nutrients.

ii) It is the structural and functional unit of the kidney.

Q 3. What is Bowman’s capsule?

Answer:

  • Bowman’s capsule is cup-shaped structure surrounding the renal corpuscle.

  • Bowman’s capsule is also known as glomerulus that helps in blood filtration.

Q 4. What’s a renal tubule?

Answer:

  • The renal tubule is the portion of the nephron containing the tubular fluid.

  • The renal tubule is filtered through the glomerulus.

  • The filtrate continues to the collecting duct system, after passing through the renal tubule.