1. Equilibrium and Negative Feedback

2. Equilibrium If something is in equilibrium it is balanced If something is in equilibrium it is balanced

3. Homeostasis The body’s way of staying stable on the inside despite what happens outside The body’s way of staying stable on the inside despite what happens outside Sweating to cool off Sweating to cool off Shivering to warm-up Shivering to warm-up

4. Negative Feedback Process that turns itself off when condition is met Process that turns itself off when condition is met Thermostat Thermostat -too hot AC turns on -Cools off AC turns off -Warms up AC turns on….

5. Negative Feedback Ex. #1 Maintaining Temperature Maintaining Temperature Body must stay at constant temperature Body must stay at constant temperature Too hot  Body Sweats Too hot  Body Sweats Too cold  Body Shivers Too cold  Body Shivers

6. Negative Feedback Ex. #2 Maintain Glucose levels Maintain Glucose levels Glucose-sugar Glucose-sugar too much or too little sugar can kill you too much or too little sugar can kill you Hormone: chemical that tells body what to do Hormone: chemical that tells body what to do Insulin: hormone that tells cells to take in sugar Insulin: hormone that tells cells to take in sugar 1. Eat sugar 2. Pancreas produces insulin 3. Tells cells to take in sugar 4. Cells take in sugar 5. Pancreas stops producing insulin

7. Diabetes Pancreas does not produce enough insulin Pancreas does not produce enough insulin Pancreas produces too much insulin Pancreas produces too much insulin Must manually regulate sugar and insulin Must manually regulate sugar and insulin

8. Negative Feedback Ex. #3 Water Equilibrium in plants Water Equilibrium in plants Diffusion: Movement of water through a membrane Diffusion: Movement of water through a membrane Moves from full to empty Moves from full to empty Moves from fresh to salty Moves from fresh to salty High to low High to low

9. Water Equilibrium in Plants Turgor Pressure: the pressure of water on a cell wall in a plant Turgor Pressure: the pressure of water on a cell wall in a plant Turgor pressure high: no water comes in Turgor pressure high: no water comes in Turgor pressure low: water moves into plant Turgor pressure low: water moves into plant *More Turgor pressure the happier a plant looks

10. Turgor Pressure

11. Negative Feedback #4 Water equilibrium in animals Water equilibrium in animals Thirsty-drink water Thirsty-drink water Kidney’s function  regulate water remove waste Kidney’s function  regulate water remove waste Too much water: urine is more clear (little urea), urinate more frequently Too much water: urine is more clear (little urea), urinate more frequently Not enough water: urine is dark (more urea), smells bad, urinate less Not enough water: urine is dark (more urea), smells bad, urinate less