Nephron Processes: Glomerular Filtration & Reabsorption Explained

Glomerular filtration: The first step in urine production is glomerular filtration, which occurs in the glomerulus. The glomerulus is a network of tiny blood vessels that are surrounded by a capsule. Blood is forced into the glomerulus, and the small molecules in the blood, such as water, electrolytes, and waste products, are forced out of the blood vessels and into the capsule. This filtrate is called glomerular filtrate.

Tubular reabsorption: The second step in urine production is tubular reabsorption, which occurs in the tubules. The tubules are small tubes that lead from the glomerulus to the collecting duct. As the glomerular filtrate flows through the tubules, some of the water and electrolytes are reabsorbed back into the blood. This process helps to regulate the body's water and electrolyte balance.

Tubular secretion: The third step in urine production is tubular secretion, which also occurs in the tubules. Tubular secretion is the process of moving substances from the blood into the tubules. This process helps to eliminate waste products from the body and to regulate the pH of the blood.

The three basic processes of nephron - glomerular filtration, tubular reabsorption, and tubular secretion - work together to produce urine. Urine is a waste product that is produced by the kidneys and is excreted from the body through the urethra.