2. AP Biology 2008-2009 Excretory System 38-3

3. AP Biology 2008-2009 Functions of the Excretory System

4. Regents Biology What liquid waste do we make?  Digesting protein makes poison  nitrogen waste = ammonia = poison H CO 2 + H 2 O NH 2 = ammonia H H N C—OH || O H | —C— | 2008-2009

5. Regents Biology Nitrogen waste disposal in water  Ammonia 2008-2009

6. Regents Biology Nitrogen waste disposal on land  Land animals  need to save H 2 O  evolved less poisonous waste product  urea  excrete urea & H 2 O as urine 2008-2009

7. Regents Biology Nitrogen waste disposal in egg  Egg-laying land animals  no place to get rid of waste while in egg  needs waste that doesn’t dissolve in water inside egg  uric acid  stays a powder, doesn’t dissolve in water  birds, reptiles, insects 2008- 2009

8. Regents Biology Uric acid  adults excrete white paste not liquid waste  white bird poop is really their pee! Getting a little personal, aren’t we! 2008-2009

9. Regents Biology  transport proteins  Waste urea leaves cell by diffusion How do animal cells regulate their contents? O2O2 sugar nutrients CO 2 urea nutrients O2O2

10. Regents Biology Organs of the Urinary System  The main organs of the urinary system are two bean-shaped kidneys.  The kidneys filter blood that contains wastes collected from cells.  It is made up of about 1 million tiny filtering units called nephrons (NEF rahnz). 2008-2009

11. Regents Biology Human kidney  Mammals have a pair of bean-shaped kidneys  Blood is supplied by a renal artery  leaves by a renal vein

12. Regents Biology  In approximately 5 min, all of the blood in your body passes through the kidneys  Approx. 2,000 L of blood is filtered daily by the kidneys. Filtration in the Kidney 2008-2009

13. Regents Biology Bladder 2008-2009

14. Regents Biology Nephron = Kidney’s filter  Blood enters the nephrons.  Cells and proteins stay in the blood  Water, sugar, salt and wastes in the blood enter the tubules in a cuplike structure in the nephron.  Its called “filtrate”  Capillaries reabsorb most of the water, sugar, and salt.  Becomes urine  to bladder

15. Regents Biology Urine  Urine exits the kidneys into ureters.  Urine flows from ureters to the bladder.  Urine flows from the bladder through the urethra and out of the body. 2008-2009

16. Regents Biology Dialysis  A person who has only one kidney still can live normally.  The remaining kidney increases in size and works harder to make up for the loss of the other kidney.  If both kidneys fail, the person will need to have his or her flood filtered by an artificial kidney machine in a process called dialysis (di AH luh sus). 2008-2009