Endocrine system & blood glucose

• The pituitary gland is also known as the master gland
• The thyroid gland produces the thyroxine hormone
• The adrenal glands produce the adrenaline hormone
• The pancreas produces the hormones insulin and glucagon
• The testes produce the hormone testosterone
• The ovaries produce the hormones oestrogen and progesterone
• Function of the thyroid

  Controls the basal metabolic rate
• Function of the adrenal glands

  Controls alertness and heart rate. Provides a fight or fight response
• Function of the pancreas


  Controls your blood glucose concentration Produces enzymes that help digest food
• Function of testes

  Sperm production
• Function of the ovaries

  Maintains the uterus lining
• Hormone

  Chemical messenger that acts on target organs in the body
• Gland

  They secrete hormones
• The endocrine system’s response is slower and includes hormones
• Function of insulin

  Restores the blood glucose to its normal level
• Glucose levels too high

  1. Pancreas releases insulin, after blood glucose levels have increased
  2. Glucose moves from blood to body cells
  3. Excess glucose is stored as glycogen in the liver and muscle cells
• Glucose levels too low

  1. Glucagon is released from the pancreas and released back into the blood
  2. Glycogen in liver and muscles is converted back to glucose
• Ways water is lost from the body

  Urine

  Sweat

  Faeces

  Exhalation via the lungs
• How are excess amino acids excreted from the body

  1. Excess amino acids are taken to the liver
  2. Their amino groups are removed as ammonia by deamination
  3. Ammonia is toxic and is quickly converted to urea
  4. Urea is excreted from our bodies by our kidneys
  5. It is then stored in the bladder and excreted as urine
• What is type 1 diabetes

  It‘s a disorder where the pancreas fails to produce enough insulin. As a result blood glucose levels are often very high
• What is type 2 diabetes

  It’s a disorder where the persons body cells no longer respond to the insulin produced by the pancreas
• How can type 1 diabetes be treated

  1. Injections before meals - allows glucose to be converted into glycogen
  2. Exercising - lowers blood glucose levels due to increased respiration in the muscles
  3. Limiting carbohydrate intake
• How can type 2 diabetes be treated

  1. Following a controlled diet
  2. Losing weight
  3. Use drugs which increase insulin production and effectiveness
  4. Regular exercise
• ADH stands for

  Anti-diuretic hormone
• How does ADH affect the reabsorption of water in the kidneys when blood is dilute

  1. More water in blood so blood is dilute
  2. Less ADH is released by the pituitary gland
  3. Less water is reabsorbed back into the blood by kidney tubules
  4. More water in urine, urine is dilute
• How does ADH affect the reabsorption of water in the kidneys when blood is concentrated

  1. Less water in the blood, blood is concentrated
  2. More ADH released by the pituitary gland
  3. More water reabsorbed by kidney tubules
  4. Less water in urine, urine is concentrated
• Two ways of treating kidney failure

  Dialysis

  Transplant
• How often is haemodialysis done

  Three times a week at hospital and takes about four hours each time
• Advantages of dialysis

  Extends life

  No risk of rejection
• Disadvantages of dialysis

  Regular hospital visits - time consuming

  Risk of infection and skin irritation
• Disadvantages of transplants

  Needs to be replaced every ten years

  Need to take immunosuppressant drugs

  Risk of rejection

  Difficult to find a donor

  Recovery from surgery will take a long time
• What is thyroxine

  A hormone released by the thyroid gland. Its release is triggered by TSH
• How is the release of thyroxine controlled by negative feedback

  1. Levels of blood thyroxine falls - detected by receptors in the brain
  2. Pituitary gland releases more TSH
  3. More thyroxine is produced and released by the thyroid gland
  4. Blood thyroxine level returns to normal
• Marathon runners often drink sports drinks to

  Replace water/ions/salt that is lost in sweat
• The liver produces urea
• The skin helps to control body temperature
• What happens to the body cells if the kidneys produce very little urine

  Cells swell or damage
• Immunosuppressant drugs are necessary to prevent rejection
• Advantages of kidney transplant

  Extends life

  No need for regular hospital visits

  Urea is minimised, so less chance of causing damage to body cells

  No repeatedly puncturing skin, so no chance of infection