1. Homeostasis An introduction

2. How well do you know yourself? It is interesting to note that though every human has a body, very few people truly understand and respect how amazing it is The human body is a self regulated machine, capable of responding to various external and internal stimuli, and initiating appropriate responses to these stimuli

3. What happens when you exercise? Think very carefully about something that more of us should be doing – exercising What happens to our bodies?

4. Your body in balance All the things you experience when you exercise are due to your body’s desire to maintain its normal functioning balance This is achieved by the cooperation of multiple systems These systems work together to sense changes and initiate responses to reverse these changes – or prevent them from worsening This normal balance within the body is known as HOMEOSTASIS – from the Greek “similar, still”

5. Call and answer The mechanism of homeostasis requires these basic components: What senses the “call” or “change”: What gives the “answer” or “tries to respond to the change”

6. Regulation of body temperature

7. Controlling the controls Homeostasis is usually regulated by feedback loops that act to prevent the initiated changes from running out of control The easiest way to understand a feedback loop is to study your thermostat

8. Your home thermostat A change in the heat in the house – for example a decrease, will be sensed by the thermostat The thermostat turns the furnace on, creating heat

9. Not unlike our own thermostat Ultimately, the hypothalamus is our thermostat The thermostat monitors internal body temperature and kickstarts changes to increase or decrease it

10. We are warm blooded Mammals, including ourselves, This is very important to human health; you should understand that from your childhood – parents become very concerned when children run a fever because it can cause major problems for the body POIKLIOTHERMS or ECTOTHERMS Reptiles can be boring to watch sometimes because their excessive sunbathing is needed to keep their body temperature regulated

11. Positive feedback In some cases, a change will initiate a larger response as opposed to shutting it off

12. http://highered.mcgraw- hill.com/sites/0072507470/student_view0/ch apter1/animation__positive_and_negative_fe edback__quiz_1_.html http://highered.mcgraw- hill.com/sites/0072507470/student_view0/ch apter1/animation__positive_and_negative_fe edback__quiz_1_.html

13. Thermoregulation in humans Short term thermoregulation in humans makes use of contracting muscles and changing blood flow If you think about the basic symptoms you experience when you’re hot or cold, you will get an idea of how the body is trying to dispel heat or retain it: