Endocrine system part 1

  1. hormone
    is a mediator molecule that is released in one part of the body but regulates the activity of cells in other parts of the body
  2. exocrine gland
    secrete their products into ducts that carry the secretions into body cavities, into the lumen of organs or to the outer surface of the body. they include sudoriferous (sweat) glands, sebaceous (oil), mucous and digestive glands
  3. endocrine glands
    secrete their products into the interstitial fluid surrounding the secretory cells rather than into ducts. They secrete hormones
  4. hormone receptors
    only the target cells for a given hormone have these that bind and recognize that hormone.
  5. receptors
    are constantly being broken down and synthesized.
  6. down regulation
    if a hormone is present in excess the number of traget cell receptors may decrease.  It makes a target cell less sensitive to a hormone
  7. up regulation
    when a hormone is deficient, the number of receptors may increase.  This makes a target cell more sensitive to a hormone.
  8. circulatory hormone
    most endocrine hormones are these.  They pass from the secretory cells that make them into interstitial fluid and then into the blood
  9. local hormone
    act locally on neighbouring cells or on the same cell that secrete them without first entering the blood stream
  10. paracrine hormones
    local hormones that act on neighbouring cells
  11. autocrine hormones
    local hormones that act on the same cell that secreted them
  12. lipid-soluble hormones
    include steroids, thyroid hormones, and nitric oxide
  13. steroid hormones
    are derived from cholesterol and are lipid soluble.
  14. thyroid hormones
    two types T3 and T4.  They are lipid soluble.
  15. nitric oxide (NO)
    the gas is both a hormone and a neurotransmitter.  It is lipid soluble.
  16. water soluble hormones
    these hormones are soluble in water and include amine hormones, peptide hormones, protein hormones and eicosanoid hormones
  17. amine hormones
    these include epinephrine, norepinephrin, and dopamine, histamine, serotonin and melatonin. they are water soluble
  18. peptide hormones and protein hormones
    are amino acid polymers ex are oxytocins and proteins include human growth hormone and insulin.
  19. eicosanoids hormones
    the two major types are prostaglandins and leukotrines.  They are important local hormones and may act as circulatory hormones.
  20. transport proteins
    most lipid soluble hormones are bound to these so they can travel in the blood. They make them temporarily water soluble. They slow the passage of small hormone molecules through the kidneys thus slowing the rate of hormone loss in urine. They provide a ready reserve of hormones already present in the bloodstream.
  21. free fraction
    some lipid-soluble hormoes are not attached to a transport protein.  The diffuse out of capillaries, bind to receptors and trigger responses
  22. first messenger
    when a water soluble hormone binds to its receptor at the outer surface of the plasma membrane
  23. second messenger
    the first one causes the creation of a second one inside the cell where specific hormone-stimulated responses take place.
  24. Cyclic AMP (cAMP)
    a second messenger
  25. target cell responsiveness
    depends on 1)hormone concentration 2)the abundance of target cell receptors 3) the influence exerted by other hormones
Card Set
Endocrine system part 1
Endocrine system part 1