Homeostasis

• What is homeostasis?

  Maintenance of a constant internal environment
• Why is homeostasis important in the body?

  It maintains pH, temperature, and water potential
• What controls homeostatic mechanisms?

  Nervous system or hormones
• What is negative feedback in homeostasis?

  Mechanism for reversing a change to return to optimum
• How does a negative feedback loop function in homeostasis?

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

  37°C
• What can extreme temperatures do to proteins in cells?

  They can denature proteins, causing cell injury
• Where is body temperature monitored and controlled?

  Thermoregulatory centre in the hypothalamus
• What role do thermoreceptors play in temperature control?

  They send nerve impulses to the hypothalamus
• How is the autonomic nervous system divided?

  Into sympathetic and parasympathetic systems
• 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 physiological responses occur if core body temperature is too high?

  • Increased sweat production
  • Hairs lie flat for heat loss
  • Vasodilation of skin arterioles
  • Reduced metabolism in liver cells
  • No muscle contractions
• What physiological responses occur if core body temperature is too low?

  • Decreased sweat production
  • Hairs raised for insulation
  • Vasoconstriction of skin arterioles
  • Increased metabolism in liver cells
  • Muscle contractions (shivering)
• What is hyperthermia?

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

  Dizziness, itchy skin, cramps, swelling
• What severe condition can result from hyperthermia?

  Heat stroke
• What is hypothermia?

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

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

  Unconsciousness and death
• What are burns classified by?

  Depth of tissue damage
• What are the degrees of burns and their symptoms?

  • Superficial: Redness, swelling, no blisters
  • Partial thickness: Blisters present
  • Full thickness: Destruction of dermis and epidermis
• How can burns lead to hypothermia?

  Excessive heat loss from moisture leakage
• What is frostbite?

  Trauma when water in cells freezes
• What areas are most affected by frostbite?

  Extremities like fingers and toes
• What are the first symptoms of frostbite?

  Cold and numbness in the affected area
• What are the potential outcomes of severe frostbite?

  • Amputation of affected areas
  • Permanent tissue damage