What is the primary role of the nephron in the kidney?

The primary role of the nephron in the kidney is filtering blood. Nephrons are the functional units of the kidney, and each kidney contains around a million of them. They play a crucial role in the body's ability to maintain homeostasis by filtering waste products and excess substances from the blood to form urine.

As blood flows through the nephron, it is filtered at a structure known as the glomerulus, where small molecules like water, glucose, and electrolytes pass into the nephron while larger molecules such as proteins and blood cells are retained in the bloodstream. This filtration process is essential for removing toxins and balancing fluids and electrolytes. The nephron then reabsorbs necessary substances back into the bloodstream and secretes waste products into the urine, highlighting its critical function in the excretory system.

While the nephron also has roles in hormone production, urine storage, and contributing to blood pressure regulation, these functions are secondary compared to its key responsibility of filtering blood, which is fundamental to kidney function and overall bodily health.