endocrine system

• Adrenal Gland

  Controls blood glucose levels
• Endocrine gland

  Glands that secrete (release) hormones directly into the bloodstream
• Testes

  Controls water balance
• Pituitary Gland

  Controls development of male sex organs. Can cause aggressive behaviour
• Hormones in the endocrine system

  • Adrenaline
  • Testosterone
  • Insulin and Glucagon
  • Oestrogen & progesterone
  • Thyroxine
  • Growth Hormone
  • LH, FSH
  • ADH
• Pancreas

  Prepares the body for flight or fight
• Speed of effect is slow in the endocrine system
• Ovaries

  Controls metabolic rate
• Thyroid Gland

  Controls development of female sex organs, and the menstrual cycle
• Hormones

  Chemical messengers made by endocrine glands and carried by the bloodstream. Cause a response in one or more specific target organs
• Endocrine gland

  • Pituitary Gland
  • Thyroid Gland
  • Adrenal Gland
  • Pancreas
  • Ovaries
  • Testes
• Endocrine system

  • Type of message: Hormones
  • What carries the message: Bloodstream
  • Number of target organs: One or several
  • Speed of reaction: Slow
  • Duration of effects: Long term
• Controlling thyroxine

  1. Thyroxine controls how much energy is available to cells

  2. Hypothalamus detects if more is needed

  3. Causes the pituitary gland to release TSH (thyroid stimulating hormone)

  4. TSH travels in the blood and causes the thyroid to release thyroxine

  5. Increases the metabolic rate in cells and energy available to cells
• Adrenaline

  • Increased heart rate: Delivers glucose and oxygen to muscles faster
  • Increased rate and depth of breathing: To cope with extra demand for oxygen
  • Blood diverted from the gut to muscles: More glucose and oxygen delivered to muscles
  • Glucose released from the liver: For increased respiration
  • Pupils dilate: Better vision (more light)
  • Hair stands on end: Appear larger, more threatening
• Thyroxine

  1. Iodine is found in many foods

  2. Thyroid gland converts iodine into thyroxine by combining it with an amino acid called tyrosine

  3. If iodine is lacking from the diet, the thyroid gland enlarges in its attempt to produce thyroxine, producing a large swelling - goitre
• Effects of adrenaline

  1. Increased heart rate: Increased rate and depth of breathing

  2. Blood diverted from the gut to muscles: Glucose released from the liver

  3. Pupils dilate: Hair stands on end
• Thyroxine

  • Released from the thyroid gland
  • Regulates the body's metabolic rate and affects most of the body's functions
• Adrenaline

  • Secreted from the adrenal glands
  • Released when scared, excited, or angry
  • Prepares the body for intense action - "fight or flight"
• Hormonal and nervous communication

  Hormonal is slower, longer lasting and less specific than nervous
• Plants do not move like animals do but they are able to respond to stimuli through tropisms
• The chemical causing phototropism