endocrine system U.4 L.9

  • hormones are chemical regulators produced by cells that affect cells in another part of the body

  • produced in glands/ secreted into the blood

  • classified by their activation site : non-target : growth hormone, insulin, epinephrine/ target : parathyroid, gastrin

  • nervous system (rapid short-term adjustments) and the endocrine system (slower, long-term adjustments) work together to control organs and tissues

  • the hypothalamus regulates the pituitary gland through nerve signal

  • the pituitary gland stimulates the endocrine glands which secrete hormones that affect the hypothalamus

  • the pituitary gland is the master gland and controls other glands :

    • posterior lobe stores and relseases hormones produced by the hypothalamus

    • anterior lobe produces its own hormones by the release is regulated by the hypothalamus

  • types of hormones :

    • steroid hormones : made from cholesterol, fat soluble, ex. sex hromones/cortisol

    • protein hormones : made from amino acids, water soluable, ex. insulin, growth hormones

  • steroid hormones :

    1. diffuse out of capillaries into target cell

    2. combine w receptors in cytoplasm or nucleus

    3. receptor-hormone complex binds to specific genes (hormone response elements)

    4. transcription occurs

    5. mRNA exits nucleus

    6. translation occurs and proteins are synthesized

  • protein hormones (second messenger system) :

    1. diffuse out of capillaries

    2. combine w receptors in cell membrane

    3. activated G protein

    4. stimulated adenylyl cyclase to produce cyclic AMP adenosine monophosphate from ATP

    5. cAMP activates target protein to phosphorylate specific proteins