Unit 4 LO5 health and social care

• Homeostasis


  Keeping a constant internal environment
• Four main conditions that need to be controlled


  • Water
  • Ion levels
  • Body Temperature
  • Glucose
• Homeostatic control


  • The endocrine and central nervous systems are the major control systems for regulating homeostasis
  • The nervous system can detect deviation from the body's normal equilibrium (state of homeostasis) and sends messages to the affected organ to counteract this disturbance
  • It restores the required balance over a relatively short time
• Kidneys


  Regulate water & mineral salts (ion) concentration
• Skin


  Regulate body temperature
• Liver & pancreas


  Regulate blood glucose level
• Parts of the body involved in Homeostasis

  • Kidney
  • Liver
  • Pancreas
  • Skin
  • Tissue cells
  • Blood
• How Homeostasis works


  1. Monitor changes that occur

  2. A negative feedback control system responds when conditions change from the ideal or set point and returns conditions to this set point

  3. There is a continuous cycle of events in negative feedback
• Feedback


  • A loop system in which the system responds to perturbation either in the same direction (positive feedback) or in the opposite direction (negative feedback)
  • Receptors are in the baroreceptor system located in the walls of certain arteries
  • The control centre is the medulla oblongata
  • The Effector is the cardiovascular system
• Changes due to temperature

  1. To keep warm: Shivering, Releasing energy from food, Vasoconstriction, Hairs stand on end

  2. To keep cool: Sweating, Vasodilation, Hairs lie flat

  3. Controlled by the hypothalamus in the brain
• Vasoconstriction


  Narrowing of blood vessels at the skin surface to reduce heat loss
• Vasodilation


  Widening of blood vessels at the skin surface to increase heat loss
• Thermoregulation


  • How we keep a steady body temperature of 37°C
  • Prevents illnesses like hypothermia and heat stroke
  • Being too hot or cold can lead to death
  • It is negative feedback as it restores temperatures to normal
• Blood Sugar-Glucose


  1. Blood sugar is maintained by insulin and glucagon secreted by the pancreas

  2. Blood sugar rises after digestion of food

  3. Pancreas secretes insulin which enables sugar uptake by cells and storage in liver and muscles

  4. Insulin decreases blood sugar levels to normal
• The conditions inside your body need to be kept steady, even when the external environment changes
• Examples of conditions that need to be kept steady

  • Water levels
  • Core Body Temperature
  • Blood Glucose levels
• Homeostasis


  The maintenance of a stable internal environment
• The body has many mechanisms to control these factors.
• Hormones are chemical messengers produced by glands in the endocrine system