Are you Kidin me?
The kidneys are two key organs that keep the blood clean and chemically balanced. The actual removal of waste happens in small units inside the kidneys called nephrons. Each kidney has about a million nephrons. In the nephron there is a glomerulus which is a tiny blood vessel or capillary intertwined area surrounded by a series of tubules which carry the urine filtrate. In a normal functioning kidney the glomerulus acts as a filtering unit and keeps proteins and cells in the bloodstream. Through this happening it allowes for extra fluid and wastes to pass through into the bowman's capsule. A chemical exchange takes place, as waste materials and water leave the blood and enter the urinary system. After the filtration process, the reabsorption process happens by the convoluted tubules and the Loop of Henele. The filtrate from the bowman's capsule passes through the proximal convoluted tubule and receives a combination of waste materials and chemicals the body can still use. Through passive transport H2O leaves the filtrate through osmosis moving from high concentration to low concentration. Active transport removes other molecules such as amino acids, glucose and sodium. The kidneys measure out the molecules like sodium and release them back to the blood to return to the body allowing the kidneys to regulate the body's level of essential molecules. Down the descending arm of the Loop of Henele, the membrane is only permeable to water allowing water to move out of the filtrate due to the concentration gradient providing passive transport. The ascending arm of the Loop of Henele is only permeable to salt which moves across the membrane through passive transport and active transport. The distal convoluted tubule allows water to exit through passive transport as well as other molecules such as potassium and sodium through active transport. The last part of reabsorption happens in the collecting duct allowing water to move passively out of the filtrate and urea to move out as well carrying the rest of the filtrate to the pelvis of the kidney, through the ureter and to the bladder for excretion. Through secretion in the tubules, chemical balances are regulated as hydrogen ions help to maintain a particular pH level. The right balance is necessary for life and regulation of the excretory system is a part of homeostasis.
Health professionals use the term "renal function" to talk about how efficiently the kidneys filter blood. People with two healthy kidneys have 100 percent of their kidney function. People born with one kidney can still function but their blood will not be filtered as efficiently. Small or mild declines in kidney function to as much as 30 to 40 percent would rarely be noticeable. For many people with reduced kidney function, a kidney disease is also present and will get worse. Serious health problems occur when people have less than 25 percent of their kidney function. When kidney function drops below 10 to 15 percent, a person needs some form of renal replacement therapy with is either blood-cleansing treatments called dialysis or a kidney transplant. |