Homeostasis and the Human Body

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Homeostasis and the Human Body
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Homeostasis

• Body equilibrium
• Stable internal environment

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Homeostatic mechanisms

• Operate at all levels
• Molecular
• Cellular
• Tissues
• Organs
• Organ Systems

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Examples of Homeostasis

• Body Temperature
• Water Balance
• Chemistry Balance of Blood

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Cooling Body Temp.

• Sweating
• Dilating Blood Vessels

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Warming Body Temp.

• Shivering
• Constriction of dermal blood vessels

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Homeostasis Examples
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1. Extracellular fluid

• The kidneys by regulating the blood composition,
  also controls the extracellular fluid homeostasis.

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2. Sleep

• Sleep timing depends upon a balance between what
  you need and what you get

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3. Hemostasis

• Hemostasis is the process whereby bleeding is
  halted.
• coagulation.

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Acid-base

• The kidneys maintain acid-base homeostasis by
  regulating the pH of the blood plasma.

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Calcium

• When blood calcium becomes too low,
  calcium-sensing receptors in the parathyroid
  gland become activated.

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Osmoregulation

• keeps the body's fluids from becoming too dilute
  or too concentrated.
• Kidneys help in this

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Sugar

• Humans regulate their blood glucose with insulin
  and glucagon.
• These hormones are released by the pancreas.

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• Blood sugar too high release insulin to balance
• Blood sugar too low release glucagon

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• If the pancreas is for any reason unable to
  produce enough of these two hormones diabetes
  results.

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Temperature

• Humans are warm-blooded, maintaining a
  near-constant body temperature.

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• Heat is mainly produced by the liver and muscle
  contractions. Humans have been able to adapt to a
  great diversity of climates, including hot humid
  and hot arid.

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BEWARE!

• Frostbite photos are graphic!

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Here are some of the conditions that can lead to
hypothermia

• Cold temperatures
• Wetness
• Improper dress/equipment
• Alcohol intake
• Poor food intake

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Mild Hypothermia

• (core body temperature ranges from 99-95 degrees
  Fahrenheit)
• Involuntary shivering
• Inability to perform complex motor functions
  (such as skiing, shooting)

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Moderate Hypothermia

• (core body temperature ranges from 95-90 degrees
  Fahrenheit)
• Slurred speech
• Violent shivering
• Dazed consciousness
• Irrational behavior (for example, the person may
  begin undressing and is unaware of being cold)
• Loss of fine motor coordination

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Severe Hypothermia

• (core body temperature ranges from 90-75 degrees
  Fahrenheit)
• Pupils are dilated
• Skin is pale
• Pulse rate decreases
• Muscle rigidity develops
• Shivering occurs in waves, it is violent and then
  pauses the pauses eventually grow longer and
  longer until shivering ceases
• Person falls to the ground and cannot walk may
  curl into a fetal position to conserve heat
• Person loses consciousness, heartbeat and
  respiration are erratic
• Cardiac and respiratory failure, then death

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• Keep the hypothermic person hydrated and fueled.
  A severely hypothermic person will be unable to
  digest solid food because the stomach may have
  shut down. Try warm sugar-water or diluted Jell-O.

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• a full bladder can mean additional heat loss.
  Urinating will conserve some heat.