Final answer:
Filtration in the kidneys is carried out by microscopic structures called nephrons, each consisting of a filtration component known as the glomerulus. The nephrons filter blood, and through a series of processes, they form urine. There are about 1 to 2 million nephrons per kidney, filtering 200 liters a day and expelling less than two liters of urine.
Step-by-step explanation:
Filtration in the kidneys is performed by microscopic structures called nephrons. Each nephron is a highly efficient microscopic tube within the kidney that filters blood and forms urine. The main filtration component of the nephron is the glomerulus, a cluster of specialized capillaries that filter blood based on particle size. Large elements such as blood cells and proteins like albumin are too large to pass through, while smaller solutes such as ions, amino acids, vitamins, and wastes are filtered to create a filtrate similar to plasma. Each kidney houses around 1 to 2 million nephrons, and together, they filter approximately 200 liters of fluid daily, out of which less than two liters are excreted as urine.
The process begins at the renal corpuscle, which consists of the glomerulus and Bowman's capsule. Fluid that passes into the nephron from the glomerulus then undergoes various processes, including filtration, reabsorption, and secretion, to eventually form urine. This urine drains into the urinary bladder for storage and is later expelled from the body through the urethra. The primary function of the nephron is maintaining homeostasis by balancing electrolytes and excreting toxins.