The Excretory System

1. The Excretory System Liquid Waste Removal System Kidshealth video Video

2. The wastes would poison you if you didn’t get rid of them. • Excretion= the process by which the body collects and removes waste produced by cells.

3. Waste removal is done by the excretory system (Kidneys, ureters, bladder, and urethra • Kidneys • The organs that filter wastes from the blood • Mostly filters out Urea • Each kidney is about the size of a fist.

4. Blood reaches the kidneys through large blood vessels • The blood vessel then branches into smaller vessels and eventually into capillaries. • Each capillary forms a tight coil called a Nephron

5. The nephron is the filtering unit of the kidney • Each kidney contains over a million nephrons

7. Capillary Coil • A Nephron is surrounded by a cuplike capsule • As blood flows through the cap. coil, some of the liquid part moves out of the cap. coil and into the capsule • The blood cells stay behind • The liquid part consists of water with materials dissolved in it.

8. The liquid contains urea and also contains substances that are not wastes, substances your body needs. • As the solution flows through a long, twisted tube, the body reabsorbs the “Good” materials, leaving urea and waste product in the tube.

9. Urine is left behind • Composed of water, urea, and other wastes • The lower urinary tract • This carries the urine away from the kidney and out of the body. • This doesn’t filter the urine in any way

10. Ureter- carries urine away from the kidney • There is one ureter from each kidney that leads into the bladder

11. Bladder • It is a muscular sac that stores urine • When the bladder is full, the muscles squeeze the urine down the urethra

12. Urethra • The tube which urine leaves the body.

13. Other excretory organs • Your lungs, skin, and liver all play a role in removing waste products from your body. • CO2 is a waste product, which is released by the lungs and blood • Perspiration • Sweat (water and dissolved waste materials) • These leave your body through your skin

14. Your liver chemically changes wastes, impurities, poisons, alcohol, and drugs to less harmful substances. • Some of these byproducts go through the kidneys and leave in the urine, others go into the small intestine and leaves with the feces.

15. Disorders of the Excretory System • Infections of the bladder and urethra • Most common excretory disorder • Symptoms= frequent urination, burning, painful feeling during urination. • These should be treated quickly • Infection could spread to the kidneys • Infections are the most common cause of nephritis • Inflammation, or swelling, of the nephrons

16. Kidney stones • Pebble like masses of salts in the kidneys or urinary tract. • Very painful when they get stuck in the urinary tract • Sometimes they can be passed, other times they need to be medically removed. • They can now be removed by an ultrasound machine

17. Uremia (yoo REE mee uh) • Poisoning of the body caused by the failure of the kidneys to remove waste from the bloodstream. • If it is due to a kidney infection, antibiotics can be used • If the kidneys stop working = kidney failure

18. Kidney failure • Must undergo kidney dialysis • A machine is used to filter blood instead of the kidneys • This takes a couple of hours every week. • Blood is removed from the body and filtered in the machine

19. Keeping the Excretory system healthy • The waste products that are filtered by the kidneys are poisons. • Drink a lot of water to dilute these poisons. Try to drink 6-8 glasses of water a day. • If you are fighting off an infection or a fever, drink more water because your system is working even harder.