Fun Fact: Though you have 2 kidneys, you can survive with 1 with no loss of life expantancy

1. Fun Fact: Though you have 2 kidneys, you can survive with 1 with no loss of life expantancy

2. Homework Check: Circulatory System

3. Excretory System • Purpose: Body system that eliminates (or excretes) nonsolid wastes through sweat, urine and exhalation to help maintain homeostasis in the body • What’s homeostasis?

4. Homeostasis • Maintaining a stable internal environment

5. Waste Products • Toxic Materials • Excess Water • Salts • Carbon Dioxide • Minerals • Vitamins • Urea (nitrogen-based)

6. Excretory System Organs • Lungs • Skin • Kidneys • Ureter • Urinary Bladder • Urethra

7. Lungs • Excrete excess carbon dioxide and water vapor through exhalation • What’s happening to the diaphragm when we exhale?

8. Skin • Contains sweat glands that release excess water and salts, and help keep the body cool (homeostasis!)

9. Ureter • Tube that carries urine from each kidney to the bladder

10. Urinary Bladder • Saclike organ that can store half a liter of urine at a time

11. Urethra • Single tube that releases urine into the outside environment

12. Kidneys • Organs that eliminate wastes by filtering and cleaning the blood to produce urine • Kidneys maintain homeostasis by: • Removing waste products from blood • Maintaining electrolyte, pH and fluid balances • Releasing hormones that do things such as regulating blood pressure

13. Nephron • An individual filtering unit of the kidney found in the cortex • Guess how many each kidney has.

14. Nephron • Our kidneys have 1 million nephrons!!!

15. Urine

16. Nephrons • Clean the blood in 3 steps: • Filtration • Reabsorption of Materials • Excretion of Materials

17. Filtration • Theglomerulus is a tangled ball of capillaries • When blood enters the glomerulus, the pressure causes small molecules to be pushed out into Bowman’s capsule • Water • Amino Acids • Salts • Glucose • Electrolytes • Urea

18. Reabsorption of Materials • Materials in Bowman’s Capsule are called filtrate • Nephrons process 180 liters of filtrate a day = too much! • 99% of filtrate gets reabsorbed in the collecting duct as needed to ensure nutrient levels are stable

19. Excretion of Materials • The Loop of Henlereabsorbs water for the last time to reduce the volume of urine • The remaining liquid is urine that leaves through the ureter

20. Diabetes • Read the article about diabetes

21. Kidney Disease • Loss of function in one or both kidneys • Two treatment options: • Dialysis • Transplant

22. Dialysis • Patients are attached to a machine that runs all of their blood through a semi-permeable membrane • A special fluid called dialysate is on the other side of the membrane, and diffusion allows for wastes to flow out of the blood • This process replicates kidney function

23. Transplant • Patients can receive kidneys from living donors (usually relatives) or nonliving donors that recently passed away • Donors and receivers must be the same blood type • If you only have 1 kidney, the other will do the work of both with little problem

24. Pig Hearts