Homeostasis An introduction. How well do you know yourself? It is interesting to note that though...
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Transcript of Homeostasis An introduction. How well do you know yourself? It is interesting to note that though...
Homeostasis
An introduction
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
What happens when you exercise?
• Think very carefully about something that more of us should be doing – exercising
• What happens to our bodies?
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”
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”
Regulation of body temperature
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
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
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
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
Positive feedback
• In some cases, a change will initiate a larger response as opposed to shutting it off
• http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter1/animation__positive_and_negative_feedback__quiz_1_.html
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: