Homeostasis

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Homeostasis
Introduction to
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Core Temperature

• Humans have a normal temperature of around
  degrees Celsius
• Body temperature goes above normal temperature
  then likely suffering from an
  and your body had to raise its temperature to
• If your body goes below this range it indicates
  . Therefore if left
  untreated it could lead to

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What is Homeostasis?

• The bodys attempt to maintain
  levels within your body
• Homeostasis is often referred to as a

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Homeostatic control systems

• 3 components
• Monitor sends a signal to the coordinating centre
  that the normal levels have changed. The
  coordinating centre then messages the regulator
  which helps restore normal balance.

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HomeostasisExample household thermostat

• Room temperature is set to 22 degrees Celsius.
  When the temperature falls below the normal
  temperature of 22 degrees, the thermostat
  recognizes change in normal temperature and
  switches on the furnace. When the thermometer
  detects a temperature above the normal, the
  thermostat switches off the furnace.

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HomeostasisExample household thermostat

• Whole control system is called a negative
  feedback system

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Negative feedback

• Process by which a mechanism is activated to
  restore conditions to their original state
• It ensures that small changes dont become too
  large.
• Why is a thermostat a negative feedback system?

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Negative FeedbackExample Thermoregulation

• The maintenance of body temperature within a
  range that enables cells to function efficiently
• Heat Stress
• Cold Stress

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Negative FeedbackExample Thermoregulation

• Heat stress
• Thermoreceptors
• Hypothalamus
• Evaporation

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Negative FeedbackExample Thermoregulation

• Heat Stress
• The hypothalamus also sends message to blood
  vessels in the skin causing them to dilate.
• allows for more blood flow
  to the skin.
• Heat from the blood is lost to the skin so blood
  can return to core of your body cool the
  internal organs.

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Negative FeedbackExample Thermoregulation

• Heat Stress
• Monitor
• Coordinating centre
• Regulator
• Result body temperature decreases hypothalamus
  turns off cooling system

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Negative FeedbackExample Thermoregulation

• Cold stress
• Thermoreceptors message the hypothalamus
• Hypothalamus sends a message via the nerves to
• Arterioles of the skin cause smooth muscles to
  contract, constricting arterioles limiting
  blood flow reduced heat loss from the skin and
  retains heat in the body.
• Smooth muscle contract that surrounds the hair
  follicles in your skin causing the hair to stand
  on end trapping warm air.
• Skeletal muscle to contract causing shivering and
  increasing your metabolism to make heat.

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Negative FeedbackExample Thermoregulation

• Cold stress
• Monitor
• Coordinating centre
• Regulator
• Result body temperature increases and
  hypothalamus turns off.

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