Endocrine

• What is the Endocrine system?

  Another system for messaging in the body, using chemicals to transmit signals instead.
• What is the main method of delivery for the endocrine system.

  The main method of delivery for the signals is in the blood, since it uses chemicals.
• The chemical message takes time to occur(slower than the nervous system) but the effect lasts longer.
• The chemicals are also known as hormones. Hormones are created in specialized glands in our body.
• Pancreas


  (a gland)Produces insulin, a hormone which tells the cells in your body to take up sugar(glucose).
• Insulin is produced when you're eating(or after a meal).
• Glucagon is produced when blood sugar levels are low.
• Glucagon is responsible for telling your body(mainly the liver) to release stored sugar into the bloodstream to be used.
• Endocrine glands are ductless glands that release hormones directly into the blood. Most endocrine glands control the internal conditions, e.g. water balance in the body, glucose levels, salt regulation and protein synthesis.
• Hormones also controls growth, development and reproduction. The hormone binds with the receptor on the target cell which in turn changes the activity within the cell. Hormones are only secreted in small amounts and are broken down in the liver to be excreted from the kidneys.
• Stimulus --> Endocrine cell receives the signal via receptor --> Hormone gets released into the blood --> Hormone binds with target cell receptor --> Response
• Like all living things plants respond to stimuli. Their responses are called tropisms.
• When a shoot grows towards the light it is called positive phototropism.
• When a root grows towards water it is called positive hydrotropism
• When a root grows down due to its sense of the pull of gravity, it is called positive geotropism.
• Auxin is a plant growth hormone that causes cell elongation. If cells on one side of a stem or a root become longer, the structure will start to bend. It works with other hormones in cell division. It is found in seed embryos, terminal buds and young leaves.
• Gibberellin affects root growth, increases stem elongation and leaf enlargement and encourages flowering, the development of pollen and pollen tubes, and fruit development.

   
• Hormone: Adrenaline

  • Source gland: Adrenal
  • Target: Whole body
  • Main effects:
  • Increases heart rate
  • Shuts down digestion
  • Makes energy available to muscles
• Hormone: Thyroxine

  • Source gland: Thyroid
  • Target: Whole body
  • Main effects:
  • Makes cells consume more oxygen and nutrients
  • Increases body temperature
• Hormone: Thyroid-stimulating hormone

  • Source gland: Pituitary
  • Target: Thyroid
  • Main effects:
  • Stimulates thyroid hormone production
• • Hormone: Follicle-stimulating hormone
  • Source gland: Pituitary
  • Target: Gonads (ovaries or testicles)
  • Main effects:
  • Stimulates egg production in females
  • Stimulates sperm production in males
• To keep cells healthy, our bodies need to cope with many changes, both internal and external. The body's ability to maintain a stable state despite these changes is called homeostasis.