How do the kidneys filter blood and maintain fluid balance?
Answer (1)
The kidneys are two bean-shaped organs located in the lower back that play a key role in filtering blood, removing wastes, and regulating fluid and electrolyte balance. Each kidney contains over a million nephrons, which are the basic filtering units.How kidneys filter blood:Filtration – Blood enters the nephron through the glomerulus, a network of capillaries. Here, water, glucose, salts, and waste like urea are filtered into the Bowman’s capsule, forming filtrate.Reabsorption – As the filtrate passes through the proximal tubule, loop of Henle, and distal tubule, useful substances like glucose, certain salts, and most of the water are reabsorbed back into the bloodstream.Secretion – Additional waste materials and excess ions are secreted into the tubules from the surrounding capillaries.Excretion – The remaining fluid, now called urine, is collected in the collecting duct, then moves to the ureters, bladder, and out through the urethra.Kidneys help maintain fluid balance by:Monitoring blood pressure and adjusting water reabsorption.Using hormones like antidiuretic hormone (ADH) and aldosterone to regulate water and sodium levels.Ensuring that waste products like urea and creatinine are removed efficiently.By constantly filtering the blood, the kidneys maintain homeostasis. Kidney failure disrupts this system and may require dialysis or transplant to take over these functions.
