3.4

• function of execratory system - responsible for removing the waste produced by the body
• waste products

  • we exhale carbon
  • when proteins are broken down, ammonia is produced
  • cells produce excess water and salt
• liver - takes ammonia from the blood and converts it into urea

  • released to blood steam where it travels urinary system
• kidneys - filter unwanted urea water and salts from the blood

  • they keep a proper amount of water in the blood
  • 180 liters of blood is filtered through the kidneys every day
• urine formation

  1. blood enters the kidney from the renal artery
  2. artery branches into smaller vessels
  3. small capillaries enter nephrons
  4. nephrons remove waste from the blood and produce urine
  5. clean filtered blood returns to the body through the renal vein
  6. urine passes into the ureters then to the bladder
• nephrons - smallest functioning unit of the execratory system, responsible for the filtration of blood and the secretion of urine
• ureters - connect kidney to bladder, carry urine
• bladder - a sac covered in muscle tissue

  • when full, muscles contract to pee
• urethra - tube that takes urine our of the bladder and out of the body
• skin - sweats to remove ecsess salt and water from body, sweat glands are located in the skin
• urine revealing diseases -

  • People whose kidneys are failing often have protein in their urine because the kidneys are not filtering properly
  • People who have diabetes will often have glucose in their urine – their cells cannot absorb glucose, and it builds up in the bloodstream
  • Because blood has so much glucose, the nephrons filter it out and add it to the urine
• dialysis

  • When someone has kidneys that do not function they are able to live thanks to a machine that acts as a kidney
  • Kidney Dialysis machine
  • Person would be hooked up to the machine and it filters blood the way the kidney does
  • It takes 4 – 6 hours to fully clean the blood