Temperature Regulation

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Temperature Regulation

• The Reverend Dr. David CM Taylor
• http//pcwww.liv.ac.uk/dcmt/Tempreg.ppt

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Why temperature regulation?

• (The 19th century experiences of puerperal fever
  and the hospital as a gateway to death are
  historical reminders of advances made.)  Birth
  is big for babies too - many changes.  Keep Baby
  warm.  In the postnatal ward, Mrs Cheung asks,
  Can I feed her?  Why are you taking my
  temperature?  Id like my aromatherapy!.

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What we will cover

• Triggered by elements in the case scenario we
  will consider
• Why we regulate temperature?
• What is meant by normal body temperature
• What mechanisms there are for regulating body
  temperature (and the importance of behavioural
  mechanisms.
• How babies are different from adults.
• How fever occurs.

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Why?

• All organisms are limited by their ability to
  survive in different temperatures
• Some, like reptiles and amphibia are
  poikilothermic
• Others like humans are homeothermic

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How?

• The actual body temperature is a consequence of
  the balance between the amount of heat produced
  and the amount of heat lost. The balance may be
  altered
• physiologically or
• behaviourally

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Balance
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Core Temperature
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So how is it regulated?
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Babies

• Babies (and hamsters) have an extra mechanism
• Brown fat.
• Suprascapular deposits
• Rich in mitochondria

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Normal body temperature

• Depends where and when you measure it
• tympanicgt oral gt axillary by 0.5oC
• can be affected by
• exercise
• emotion
• time of day

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And the menstrual cycle (o- p)
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Fever

• monocytes and phagocytes release endogenous
  pyrogen (Interleukin-1, IL-1).
• The anterior hypothalamus is sensitive to IL-1
• Hypothalamic sensitivity to temperature is
  altered.

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So

• The body temperature then becomes regulated at a
  new, higher level.
• There is some evidence that the raised body
  temperature enables the fight against the
  infection.

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But...

• Every 1OC rise in temperature increases basal
  metabolic rate and oxygen consumption by about
  13,
• In acute infection, the ability to mobilise fat
  stores is inhibited.

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Consequently

• Skeletal muscle is broken down and the amino
  acids are used in gluconeogenesis.
• This can be debilitating.

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And even worse

• In addition to the increased demand for energy
• Temperatures (above 42OC) damage nerve cells
• impair thermoregulation
• have more serious consequences.

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