THE ENDOCRINE SYSTEM

THE ENDOCRINE SYSTEM

1. has two primary

   • HORMONES
     • released by
       • GLANDS
         • PITUITARY GLAND
           • located at
             • base of brain
               • attached to the
                 • hypothalamus
           • which
             • stores and produces hormones
           • composed of
             • two separate lobes
               • posterior lobe
                 • produces
                   • antidiuretic hormone
                     • which
                       • regulates body water
                   • oxytocin
                     • which initiates
                       • strong uterine contractions during labour
               • anterior lobe
                 • releases
                   • thyroid stimulating hormone
                     • as well as
                       • adrenocorticotropic
                         • stimulates
                           • adrenal cortex
               • regulated by
                 • hypothalamus
                   • relaxing factors are
                     • dopamine
                       • which
                         • inhibits secretion of prolactin
                           • stimulates
                             • milk production
                     • somatostatin
                       • which
                         • inhibits secretion of somatotropin
                           • stimulates
                             • growth of the long bones
         • THYROID GLAND
           • located
             • front of neck, in front of trachea
           • contains
             • four parathyroid glands within
               • produce
                 • parathyroid hormone
                   • which
                     • increase calcium levels in blood and lower phosphate levels
           • produces
             • thyroxin and triiofothyronine
               • which
                 • increase metabolism and limit growth
                 • require iodine present in thyroid for production
         • ADRENAL GLAND
           • located above
             • kidneys
           • composed of
             • adrenal medulla
               • and the
                 • adrenal cortex
                   • produces
                     • glucorticoids
                       • which affects
                         • blood glucose levels
                       • such as
                         • cortisol
                     • mineralcorticoids
                       • which
                         • water balance
                       • such as
                         • aldosterone
                     • sex hormones
               • produces
                 • epinephrine and noepinephrin
                   • creates our
                     • fight or flight response
         • PANCREAS
           • located
             • in abdomen
           • hormone producing cells of pancreas are located in
             • islets of Langerhans
               • produce
                 • insulin
                   • produced by
                     • beta cells
                   • released when
                     • blood sugar rises
                   • causes
                     • cells of muscles, liver and organs to become permeable to glucose
                     • liver to convert glucose to glycogen
                       • which
                         • primary storage of glucose
                         • lowers blood sugar
                 • glucagon
                   • produced by
                     • alpha cells
                   • released when
                     • blood sugar is low
                   • promotes
                     • conversion of glycogen to glucose
                       • which
                         • raises blood sugar
     • one being
       • STEROID HORMONES
         • made from
           • cholesterol
             • examples are
               • sex hormones and cortisol
                 • which
         • are
           • fat soluble
             • therefore
               • diffuse from capilaries
                 • into
                   • target cells
                     • which activate
                       • specific protein synthesis
       • the other being
         • PROTEIN HORMONES
           • are
             • water soluble
               • therefore
                 • combine with receptor sites of cell membranes
                   • causes
                     • adenylyl cyclase sythesis
                       • which
                         • converts ATP to cyclic AMP
                           • which
                             • activates enzymes
           • made from
             • chains of amino acids
               • examples are
                 • growth hormones and insulin
                   • which
     • provide control of
       • organs and tissues

2. diagram

3. DISEASES

   • diabetes
     • insufficient production of insulin
   • hyperthyroidism
     • overproduction of thyroxine can cause weight loss and high blood pressure.
   • hypothyroidism
     • lack of thyroid causes myxedema
       • dry skin, weight gain, edema
   • goiter
     • Inadequate iodine in thyroid causes enlargement of thyroid gland
   • dwarfism
     • low secretion of somatotropin during childhood can cause dwarfism

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