Final answer:
The nephron is the key functional unit of the kidney responsible for blood filtration, nutrient and water reabsorption, and waste product secretion. These processes ensure body fluid homeostasis and toxin elimination.
Step-by-step explanation:
The nephron is known as the functional unit of the kidney, tasked with the regulation and filtering of blood to form urine. This is achieved through three primary functions: glomerular filtration, tubular reabsorption, and tubular secretion.
Filtration occurs in the renal corpuscle; here, blood pressure forces water and small solutes out of the blood through a sieve-like membrane into Bowman's capsule. Reabsorption takes place primarily in the proximal convoluted tubule, the loops of Henle, and the distal convoluted tubule, where necessary nutrients, ions, and water are reabsorbed into the bloodstream. Lastly, secretion occurs mainly in the distal convoluted tubule; this is where additional waste products and excess ions are actively transported from the blood into the tubular fluid.
Aside from its primary roles, the nephron also performs secondary functions related to blood pressure regulation through renin production, red blood cell production via erythropoietin (EPO), and enhancing calcium absorption by converting calcidiol to calcitriol, the active form of Vitamin D.
Final answer in two line explanation in 300 words: The nephron filters the plasma to maintain homeostasis and excretes toxins through urine formation, achieved via filtration, reabsorption, and secretion.