Introduction
The nephron is the functional unit of the kidney. Each kidney contains about one million nephrons, essential for filtering blood and forming urine. This guide will explain the nephron’s structure and its vital role in maintaining our body’s health.
Structure of a Nephron
- Bowman’s Capsule
- A cup-shaped structure encasing the glomerulus.
- Collects the filtrate from the blood.
- Glomerulus
- A network of capillaries.
- Filters blood through high pressure, pushing water and solutes into the Bowman’s capsule.
- Proximal Convoluted Tubule (PCT)
- A twisted tubule where most reabsorption occurs.
- Reabsorbs water, ions, and nutrients back into the blood.
- Loop of Henle
- A U-shaped loop extending into the kidney’s medulla.
- Descending limb reabsorbs water; ascending limb reabsorbs sodium and chloride ions.
- Distal Convoluted Tubule (DCT)
- Adjusts the filtrate further by reabsorbing more ions and secreting waste products.
- Collecting Duct
- Several nephrons drain into one collecting duct.
- Concentrates urine as it moves towards the renal pelvis, then to the ureter.
Functions of a Nephron
- Filtration
- Blood enters the glomerulus under high pressure.
- Water and small solutes filter into the Bowman’s capsule, forming the filtrate.
- Reabsorption
- Essential substances are reabsorbed in the PCT, Loop of Henle, and DCT.
- Reabsorbs water, glucose, amino acids, and ions to maintain electrolyte balance.
- Secretion
- Additional waste products and excess ions are secreted into the nephron.
- Occurs mainly in the PCT and DCT.
- Excretion
- Remaining filtrate, now called urine, is collected in the collecting duct.
- Transported to the renal pelvis, then to the ureter, and finally stored in the bladder.
Conclusion
Understanding the nephron, the functional unit of the kidney, helps us appreciate how our kidneys filter blood, balance fluids, and remove waste. This intricate process is crucial for maintaining overall health and homeostasis.
For more information on kidney functions and health, visit Kidney.org.