The kidneys

    Cards (25)

    • The role of the kidneys is to regulate the water content of the blood and to excrete toxic waste products of metabolism
    • Blood is brought to the kidneys in renal artery which branches off aorta
    • Kidneys regulate water and salt content and removes urea
    • Filtered excess water, salts and urea form urine
    • Urine moves to bladder to be excreted
    • Purified blood returns through the renal vein and into heart through vena cava
    • Kidney is packed with a million nephrons
    • Nephrons are what regulates water and salt levels and removes urea
    • ADH stands for anti diuretic hormone
    • Water content of blood is controlled by the hormone ADH
    • DIfferent amounts of ADH are released into blood stream by a gland in the brain according to concentration
    • The concentration of blood can be altered by
      -excess drinking
      -excess sweating
      consumption of salty foods
    • If there is high concentration in plasma, the issue is there's too little water so ADH release increases so more water is reabsorbed by nephrons and the urine becomes more concentrated
    • If there is a low concentration in the plasma the issue is that there's too much water so ADH release increases and less water is reabsorbed by nephrons and the urine becomes more dilute
    • Pituitary gland releases ADH
    • If more ADH released then there is less water lost in urination
    • Selective reabsorption is when useful substances like glucose, right amount of water and some ions are reabsorbed
    • Dialysis is when machines filter the blood
    • Dialysis has to be done regularly to keep concentrations of dissolved substances in blood at normal levels and remove waste products
    • If you get kidney failure you either need dialysis or a transplant
    • If kidneys don't work properly, waste substances build up in the blood and you loose your ability to control ion and water levels resulting in death
    • Concentration of urine is controlled by ADH which is released into the blood by the pituitary gland
    • If water content is too high, less ADH released so less water reabsorbed by kidneys
    • There has to be a constant balance of water in the body
    • We loose water from the skin and lungs and we can't control how much in these ways so it's balanced by what we consume and what's lost in urine
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