What are kidneys used for?

Answer 1

The kidneys act as if they were a filter. They remove wastes (mostly liquids) from the blood, and have some control of your blood pressure.
Kidneys are vital organs that function to keep the blood clean and maintain chemical balance within. They process blood to extract waste products and extra water. These by products become urine to be ultimately excreted from the body.

The kidney serves many important functions, including:

1. Filtering out wastes to be excreted in the urine.
2. Regulating blood pressure via both urinary excretion of wastes and initiating the renin-angiotensen hormone regulatory system
3. Regulating an acid-base balance via the bicarbonate system
4. Stimulating red blood cell production via the release of the hormone erythropoietin.

Interesting fact: We have two kidneys to get the filtering done well. Well enough to filter our blood entirely - several times every five minutes.

The human kidneys are a pair of organs that help to maintain proper water and electrolyte balance, regulate acid-base concentration, and filter the blood of metabolic wastes, which are then excreted as urine. Along with the liver, the kidneys keep the bloodstream clean and the blood at the proper thickness and pressure.

The kidneys' main function is as a homeostatic regulator. Your body has equilibrium levels for salt content, water content, core temperature, blood pressure and blood volume. The kidneys help to maintain these equilibrium levels, mainly the cardiovascular components. For example, they regulate blood pressure and volume through the absorption of water from the blood.
The kidneys are an essential part of the urinary system and also serve homeostatic reasons such as the regulation of blood pressure and acid-base balance. They take out waste such as urea and ammonium; also responsible for reabsorpitation of water, glucose, and ammonium acid.
Function

• Ultrafiltration: the process by which fluid is filtered out of the blood by the glomerulus.
• The blood pressure in a glomerulus causes part of the blood plasma to leak through the capillary walls. The red blood cells and plasma proteins are too big to pass out of the capillary, so the fluid that does filter through is plasma without the protein. The fluid thus consists mainly of water with dissolved salts, glucose, urea and uric acid.
• Selective Reabsorption: the process of absorbing back the substances needed by the body.
• The filtrate from the glomerulus collects in the renal capsule and trickles down the renal tubule.
• As it does so, the capillaries which surround the tubule absorb the substance the body needs back into the blood.
• ** The glucose is reabsorbed with much of the water.
  • Some of the salts are taken back to keep the correct concentration in the blood.
  • *** Salts not needed by the body are left to pass down the kidney tubule with the urea and uric acid.
    • They continue down the renal tubule into the pelvis of the kidney, passes down the ureter and to the bladder.
• Urine cannot escape from the bladder because a band of circular muscle, called a sphincter, is contracted, so shutting off the exit. When it relaxes, the muscular walls of the bladder expel the urine through the urethra.
• ** Adults can control this sphincter muscle and relax it only when they want to urinate.
  • In babies, the sphincter muscle relaxes by a reflex reaction, set of off by pressure in the bladder.

Water balance and osmoregulation

• The body:
• ** Gains water from food and drink
  • Loses water by evaporation, urination and defececation.
  • *** Evaporation from the skin takes place all the time but is particularly rapid when we sweat.
    • Air from the lungs is saturated with water vapor which is lost in the atmosphere when we exhale.
• Despite these gains and losses of water, the concentration of body is kept within very narrow limits by the kidneys, which adjust the concentration of blood flowing through them.
• ** If the blood is too dilute, less water is reabsorbed from the renal tubules, leaving more to enter the bladder.
  • If the blood is too concentrated, more water will be absorbed back into the blood from the kidney tubules.
• A rise in blood concentration is thought to stimulate a thirst center in the brain. The drinking which follows this stimulation restores the blood to its correct concentration.
• Osmoregulation: the regulatory processes that keep the blood at a steady concentration.
• • One example of the process of homeostasis

The kidney is used to excrete liquids from the body to the urinary tract in order to get rid of wastes and excess minerals.
Anatomy. Either one of a pair of organs in the dorsal region of the vertebrate abdominal cavity, functioning to maintain proper water and electrolyte balance, regulate acid-base concentration, and filter the blood of metabolic wastes, which are then excreted as urine.

they remove carbon dioxide from the blood and send it to the lungs.
the blood that enters the kidneys contains poisonous nitrogen wastes , as well as other wastes produced by body cells . Each kidney has about one million tiny tubes that filter wastes from the blood. Blood that has been cleaned by the kidneys returns to the heart to be pumped to other parts of the body . Urine passes slowly from the kidneys into the urinary bladder where the urine is stored until you are ready to empty your bladder