1. How The Body Responds

2. Changes Close your eyes… I am going to give you a scenario to imagine… Really close your eyes… I will say a series of sentences and I want you to tell me your initial emotional reactions Ready? Your parents got new jobs and you are going to have to move to Togo. You just found out that your best friend is hanging out with the new kid in class behind your back. I am about to sneak up behind you while your eyes are closed and buzz your hair!

3. Changes At least one of the previous statements might have made you feel a little unsettled That is because humans often resist change We really enjoy the fact that things will remain consistent The human body works in a very similar manner

4. Homeostasis The human body works more efficiently when it can maintain a certain set of internal conditions This also helps prevent harmful changes in internal conditions Homeostasis is the ability to maintain a set of stable internal conditions Homeostatic regulation are the physiological changes needed to maintain homeostasis FUN FACT: Every death in human history is due to a loss of homeostasis

5. Homeostasis Homeostasis can be maintained two different ways Autoregulation is the way to maintain homeostasis that comes from within a cell, organ or organ system An example is when oxygen levels decline in an organ system Cells will produce chemicals to dilate blood vessels in order to get more oxygen

6. Homeostasis Extrinsic regulation is when the activities of an outside system (mostly nervous or hormone) regulate homeostasis An example of this is when you work out Based on your level of activity, your nervous system sends signals to your heart to beat faster to maintain proper oxygenation of cells

7. Homeostatic Regulators Regardless of the systems or mechanisms involved it is the job of the body to maintain homeostasis Each homeostatic regulator has three basic parts A receptor responds to a stimulus A control center receives and processes the information An effector makes a change based on the stimulus

8. Homeostatic Regulators It is very similar to the way you regulate temperature in your house A small thermometer detects the temperature of the house (receptor) A thermostat detects this information and decides to turn on the air conditioning (control center) The air conditioner will turn on (effector)

9. Homeostatic Regulators The set point is the desired value that the control center tries to maintain Often the level of homeostasis will fluctuate around the set point by a small percentage Fulgurations are not generally not a problem as long as they are not too large

10. Feedback Lets try a fun exercise! Turn to the person next to you and give them some observations about their outfit These observations can be constructive criticism or they can be complements, it is up for you to decide Hopefully that was not too traumatic of an experience

11. Feedback What you just received from the person next to you was called feedback Feedback is information that is given to an organism that allows them to understand their environment better In this scenario the feedback you gave to your partner next to you was based on their appearance in this classroom

12. Positive Feedback Positive feedback is a type of feedback that produces a larger or exaggerated response based on the feedback For example, if you told your partner that they had a really nice pair of shoes, they might be included to wear those shoes more The feedback you gave will cause them to have a larger positive response the next time the see those shoes in the closet

13. Positive Feedback Positive feedback is used in the body, but it is pretty rare This is because it tends to lead to very extreme responses to stimuli One example is if you receive a large cut or wound The release of blood clotting factors by a small amount of cells will stimulate the release of other clotting factors in other cells

14. Positive Feedback http://www.youtube.com/watch ?v=65U3NSDn2dg&t=6m41s http://www.youtube.com/watch ?v=65U3NSDn2dg&t=6m41s

15. Negative Feedback Negative feedback is a type of feedback that leads to counteracting the feedback When you asked the person to evaluate your outfit they may have been a bit critical of your shirt Next time you see the shirt in the mirror, you may not be as inclined to wear that shirt

16. Negative Feedback This happens frequently in the body Thermoregulation is the regulation of body temperature When your hypothalamus receives information that your body is above ~37.2 O C your body sets things in motion that will cool your body This will bring your body below 37.2 O C

17. Equilibrium Homeostatic regulation is not an easy thing for a body to achieve It often takes many integrated organ systems to help maintain homeostasis It often takes many different organs releasing signals, turning on and off feedback loops and coordinating set points

18. Equilibrium A state of equilibrium is maintained when several processes are balanced and homeostasis is maintained This is a scenario that allows allow all body systems to function at a high potential