1. The Excretory System

2. Excretory System Why do our bodies need to filter waste from the body? – –Maintain homeostasis – –Removal of harmful materials – –Removal of excess fluids, chemicals, minerals, vitamins, salts, and other wastes from the blood

3. Organs of the Excretory System sweat glands lungs

4. The Excretory System Functions The excretory system collects wastes produced by cells and removes them from the body – –Urea (waste from breakdown of protein) helps maintain homeostasis by maintaining water balance and eliminating liquid waste

5. Organs of the Excretory System kidneys – major organs of the excretory system that filters blood and eliminates urea, excess water, and other wastes

6. Organs of the Excretory System

7. ureters – two narrow tubes that urine flows through to get to the bladder

8. Organs of the Excretory System urinary bladder – sac-like, muscular organ that stores urine

9. Where is urine stored until the body is ready to eliminate it? 1. 1. Kidneys 2. 2. Ureters 3. 3. Bladder 4. 4. Urethra

10. Organs of the Excretory System urethra – tube that urine travels to leave the body

11. The Filtering Process Every drop of blood in your body passes through the kidneys and is filtered 300 times a day nephrons – tiny structures that filter blood in the kidneys

12. Filtering Out Waste After entering the kidneys, blood flows through smaller and smaller arteries The blood eventually reaches a cluster of capillaries called nephrons In the nephron, urea, glucose, other chemicals, and some water move out of the blood and into the nephron

13. Filtering Out Waste Blood cells and proteins stay in the capillaries Glucose, water, and small amounts of other substances are reabsorbed into the blood stream Urea and other wastes stay in the nephrons

14. Filtering Out Waste The liquid left in the tube is urine The urine moves down the ureters and into the bladder When the bladder is full, you feel the urge to urinate

16. Filtering Summary 1. both wastes and needed materials are filtered out of the blood 2. the needed material is returned to the blood 3. the waste is eliminated in the urine

17. Analyzing Urine Some medical problems can be found by testing urine Glucose – diabetes Protein – kidney failure Drug residue – drug abuse

18. Functions of Excretory System Rids blood of wastes (urea) Controls blood volume by removing water extra water cells produced by cells salts Balances salts and water water so cells can function properly

19. Which is not a function of the excretory system? 1. 1. Removes wastes from the blood 2. 2. Removes excess water from the blood 3. 3. Removes carbon dioxide from the blood 4. 4. Removes excess salt from the blood

20. Other Organs of Excretion There are other organs in our body that can excrete substances Lungs – carbon dioxide and water Skin – sweat, water, some chemicals Liver – breaks down molecules, recycles hemoglobin and turns it into bile

21. Which system does not include an excretory organ? 1. 1. Excretory system 2. 2. Integumentary system 3. 3. Cardiovascular system 4. 4. Respiratory system

23. Body systems that work with the excretory system; circulatory system to carry waste to the kidneys respiratory system to remove carbon dioxide integumentary system to remove salt

24. Comparing Cells to Body What cell organelle helps to break down waste? What cell organelle packages waste? golgi body lysosomes