The Excretory System

By Grace and Douglas

What does it do?

The Excretory system produces, stores and carries urine through the body and removes cellular waste. The system also maintains the salt-water balance in an organism.
It is made up by the kidneys, urinary bladder, ureters, sphincter muscles, and urethra.

Diagram of the Excretory System

  1. Urine goes through the kidney for filtration
  2. Goes down the ureters into the bladder for temporary storage
  3. Bladder gets too full nerve endings send messages to the brain
  4. Brain triggers the walls to become smaller and the sphincter to relax
  5. Urine goes through the sphincter muscle to the urethra
  6. The urethra lets the urine flow out of the body


  • Removes urea, toxins, medications, excess ions-form urine
  • Also returns needed materials to the blood
  • The kidneys filter about 162 quarts of blood a day


    • Ureters- carry urine from the kidneys to the bladder
    • 10-12 inches and run along the left and right of the vertebral column
    • Walls-peristalsis of smooth muscle tissue


    • Bladder- muscular organ, bottom of the abdomen, and expands as it fills with urine
    • When bladder is full nerve endings, in the bladder wall, send signals to brain
    • The brain trigger the bladder walls to become smaller and the sphincter to relax

      Sphincter Muscle

      • Controls the urine flow from the bladder to the urethra
      • Tube that carries urine from the bladder and outside the body
      • Muscle surrounds urethra


      • The Urethra is a small tube from bladder to outside of the body
      • Empties the urine


      • Urinary tract infections= UTI
        • Ex: cystitis- inflammation in the urinary bladder
      • Kidney stones- solid salt crystals
        • Can damage the urinary passages-cause major pain and bleeding*
      • Shock wave treatment- disintegrates the stone from the outside
      • Renal failure-kidneys lose the power to function
        • Can cause death if left unchecked

      Working With Other Systems

      • Excretory system is close to the circulatory and endocrine system
      • Endocrine system- major controller of the excretory system
        • monitors levels of solids and
      • To keep the best internal environment for you cells your kidneys must continually change

      Extra Information

      • Skin- organ of excretion
        • removes water of urea and salts (sweat)
      • The kidneys-remove urea, toxins, medictions, excess ions-form urine
        • Also return needed materails to the blood