Thermostats set point is 75ºF Inside temperature heat 72ºF 73ºF 74ºF 75ºF Definition The body maintains a constant internal environment Importance Body processes work best in specific conditions ID: 777053
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Slide1
Homeostasis
Slide2Homeostasis is like your home’s thermostat
Thermostat’s set point is 75ºF
Inside temperature =
heat
72ºF
73ºF
74ºF
75ºF
Slide3Definition: The body maintains a constant internal environment
Importance
: Body processes work best in specific conditions
Slide4Control System
Sensors
Gather information about the internal and external environment
Ex: pressure sensors in your foot
Communication systemimpulse (message) sent through the body Ex: nerves connected from foot to brain.Control CenterInterprets sensory information
Ex: Brain interprets pain in foot.TargetsBody part that receives the final messageEx: Muscles in foot, muscles in jaw
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Slide5Negative Feedback Loops
Reverses any change that moves conditions from a set point
Ex: if your temp drops…you will shiver to reverse that
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Slide6Negative Feedback Loops
Reverses any change that moves conditions from a set point
Ex: if your temp drops…you will shiver to reverse that
Ex: If your temp rises…you will sweat to reverse that
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Slide7Negative Feedback Loop: Cold Response
Slide8Positive Feedback Loop
Increases the changes away from set points
Important when rapid change is needed
Ex: Pregnancy contractions
Uterus contractions begin slowlyOxytocin released to speed up the contractions
Slide9More examples…
Growth hormones stimulate cell division
Torn
vessel stimulates release of clotting factors
platelets
fibrin
white blood cell
red blood cell
blood vessel
clot
Positive Feedback Loop
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Slide10Working Together
Thermoregulation: Maintenance of body temperature
Skin (sensors): sensors detect cold
Nervous system (communication system): electrical impulse sent to brain
Hypothalmus
in brain (control center): releases hormones into blood streamMuscles (target) : Hormones cause shivering
Slide11Some disruptions are temporaryInfections, fever, sore throats, muscle soreness
Some disruptions are too great for your body to control
Frost bite: Sensors are destroyed
Paralysis: Messages from brain can’t reach targetCan lead to death
Beck Weathers, thought to be dead, survived a night exposed to Mt. Everest cold.
Homeostasis disruption
Slide12Diabetes: inability to control blood sugar
Normally
Glucose in blood rises after meals
Pancreas releases insulin
Cells remove the glucoseType 1Immune system destroys pancreas cellsPancreas unable to make insulinBlood pH decreases as glucose builds up
Type 2Pancreas does not make enough insulinBlood pH decreases as glucose builds up
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Slide13Review
Define homeostasis.
Name and describe the four parts of the “control system.”
What is negative feedback?
What is positive feedback?
Is the following example positive or negative feedback? During heavy exercise your body loses water when you sweat. As a result of water loss, your body redirects the remaining water inside your body to vital parts of your body to replenish these vital organs.
What is diabetes?How does Type I and Type II diabetes differ?