Lesson 6

• What is homeostasis?

  The process of maintaining a constant internal environment
• Why is homeostasis important in the body?

  It maintains pH, temperature, and water potential
• How are homeostatic mechanisms controlled?

  Using the nervous system and/or hormones
• What is negative feedback in homeostasis?

  A mechanism for reversing a change to return to optimum
• What are the stages of negative feedback?

  1. Stimulus
  2. Receptor
  3. Co-ordinator
  4. Effector
  5. Response
• What happens in a negative feedback loop?

  A change away from normal triggers counteractions
• What is the normal human body temperature?

  Approximately 37°C
• What can extreme temperatures cause to proteins?

  Proteins in the cell membrane can denature
• Where is body temperature monitored and controlled?

  By the thermoregulatory centre in the hypothalamus
• What does the thermoregulatory centre monitor?

  The temperature of the blood
• What type of nervous system controls body temperature?

  The autonomic nervous system
• How are the sympathetic and parasympathetic systems related?

  They act antagonistically to each other
• What does the sympathetic nervous system do?

  It speeds up or increases body processes
• What does the parasympathetic nervous system do?

  It slows down or decreases body processes
• What happens when body temperature gets too high?

  1. Detected by thermoreceptors in the skin
  2. Nerve impulse sent to the hypothalamus
  3. Vasodilation occurs
  4. Sweating increases
  5. Hairs lie flat
• What happens when body temperature gets too low?

  1. Detected by thermoreceptors in the skin
  2. Nerve impulse sent to the hypothalamus
  3. Vasoconstriction occurs
  4. Sweating stops
  5. Hairs stand proud
• What are the physiological responses if core body temperature is too high?

  • Increased sweat production
  • Hairs lie flat
  • Vasodilation occurs
  • Increased blood flow to skin
• What are the physiological responses if core body temperature is too low?

  • Decreased sweat production
  • Hairs stand proud
  • Vasoconstriction occurs
  • Reduced blood flow to skin
• What is hyperthermia?

  Body temperature higher than normal
• What are symptoms of hyperthermia?

  Dizziness, cramps, and heat exhaustion
• What severe condition can hyperthermia lead to?

  Heat stroke
• What is hypothermia?

  Core body temperature falls below 35°C
• What are symptoms of mild hypothermia?

  Shivering, tiredness, and confusion
• What can severe hypothermia lead to?

  Unconsciousness and death
• What are the degrees of burns classified by depth?

  1. Superficial
  2. Partial thickness
  3. Full thickness
• What are the symptoms of superficial burns?

  • Redness and swelling
  • Minimal tissue damage
  • Moist skin surface
  • Painful
• What are the symptoms of partial thickness burns?

  • Redness and swelling
  • Blisters present
  • Painful
• What are the symptoms of full thickness burns?

  • Destruction of dermis and epidermis
  • Relatively painless
• What can burns lead to?

  Hypothermia due to heat loss
• What is frostbite?

  Trauma when water in cells freezes
• What are the first symptoms of frostbite?

  Cold and numbness in the affected area
• What are the common areas affected by frostbite?

  • Face (nose, cheeks, chin, ears)
  • Fingers
  • Toes