1. AIM: How does excretion in humans remove harmful wastes?

2. Your Body’s Filter Have you ever seen a water-purification system attached to a faucet? This system removes impurities from the water such as arsenic or other chemicals that can be harmful to people. As water passes through the filters contained in the system, the impurities are trapped on the surface of the filters. Eventually, the water that comes out of this purifier is free of the impurities. 1. Your body has its own system for filtering blood. Why might the blood in your body need to be filtered? 2. What organs do you think filter your blood? 3. How do you think the filtered materials leave your body?

3. Urinary System Blood in the artery enters the kidney In the kidney the blood gets cleaned of metabolic waste The vein carries clean blood back to the heart The ureter carries urine to bladder Label the Diagram

4. Urinary System The bladder is where urine is stored When the bladder is full, it sends a message to the brain The urine (water, urea, & other wastes) exits the body through the urethra.

6. Kidneys: How do they maintain homeostasis? The primary organs in excretion, play a vital role in maintaining the homeostasis of body fluids. They excrete waste products & regulate water & salt balance in the blood.

7. Nephron Made of millions of nephrons which filter the blood of SALT, WATER, and UREA.

8. Nephron Parts of the Nephron: 1)Glomerulus – tiny ball of capillaries located at the beginning of each nephron tubule. 2) Bowman’s Capsule – cup- shaped portion of the nephron that surrounds the Glomerulus, collects stuff filtered from the blood

9. Nephron Blood Processing: 1)Filtration – blood pressure forces fluid (water, urea, glucose, amino acids) from the glomerulus into the Bowman’s Capsule (not proteins). 2)Reabsorption – water and dissolved nutrients, such as glucose, salts, & amino acids, are reabsorbed back into the blood.

10. Nephron Blood Processing: 3)Secretion – kidneys remove certain substances from the blood and add them to the filtrate. 4)Excretion – now the filtrate is called urine and will be sent to the ureter, the bladder, & then the urethra to be excreted from the body.

11. Other Excretory Organs Liver Lungs Skin

12. LIVER Destroys old RBCs Produces urea from breaking down amino acids (ammonia to urea) Stores glycogen Detoxifies many harmful substances

13. Lungs Gets rid of :____ & _____

14. Skin (Integumentary) Gets rid of extra heat Gets rid of water and salt Has 2 to 5 million sweat glands Sweat Gland

15. How does our excretory system help maintain homeostasis? Temperature balance Water balance Waste balance Gas balance