ENDOCRINE SYSTEM (HOMEOSTASIS)

• Endocrine system


  Composed of glands which secrete chemicals called hormones directly into the bloodstream
• Endocrine glands


  • Pituitary gland
  • Pancreas
  • Thyroid
  • Adrenal gland
  • Ovary
  • Testes
• Insulin


  Hormone produced by the pancreas that causes glucose to move from the blood into cells
• Type 1 diabetes is a disorder in which the pancreas fails to produce sufficient insulin. It is characterised by uncontrolled high blood glucose levels and is normally treated with insulin injection
• Blood glucose concentration


  Monitored and controlled by the pancreas
• If blood glucose concentration is too high

  1. Pancreas produces insulin

  2. Insulin causes glucose to move from blood into cells

  3. Excess glucose converted to glycogen for storage
• Type 1 diabetes


  • Pancreas fails to produce sufficient insulin
  • Characterised by uncontrolled high blood glucose levels
  • Normally treated with insulin injections
• If blood glucose concentration is too low

  1. Pancreas produces glucagon

  2. Glucagon causes glycogen to be converted into glucose and released into blood
• Negative feedback cycle


  Glucagon and insulin control blood glucose levels
• Osmotic changes in body fluids


  Effect on cells
• Ways water, ions and urea leave the body

  • Lungs during exhalation
  • Skin in sweat
  • Kidneys in urine
• Deamination of excess amino acids

  Converts ammonia to urea for safe excretion
• Kidney function


  1. Filtration of blood

  2. Selective reabsorption of useful substances
• Knowledge of other parts of urinary system, kidney structure, and nephron structure not required
• ADH


  Increases permeability of kidney tubules to water
• Kidney dialysis


  Treats kidney failure
• Advantages and disadvantages of treating organ failure by mechanical device or transplant should be evaluated