Digestive Page 3 (cont.)

                                    a.    Factors effecting histamine release 
                                          1.    Increases release
                                                 a.    gastrin binds CCK-B 
                                                        receptors on ECL cells
                                                 b.    parasympathetic nervous 
                                                        system releases Ach that 
                                                        binds M1 receptors
                                                        on ECL cells
                                                 c.    sympathetic nervous 
                                                        system
                                                        releases NE that binds 
                                                        beta receptors
                                                        on ECL cells     
                                           2.    Decreases release
                                                  a.    somatostatin binds ST-2 
                                                         receptors
                                                         on ECL cells
                                                  b.    histamine downregulates its 
                                                         own release and synthesis 
                                                         by combining to H3 
                                                         receptors on ECL cell
                                     b.    Functions of histamine
                                            1.    acts on parietal cells by binding 
                                                   H2 receptors to increase HCL 
                                                   release from parietal cells
                                                   a.    effects blocked by H2 
                                                          blocking drugs
                              3.    somatostatin (from D cells in the fundus 
                                     and pyloric antrum)
                                     a.    Pyloric antrum D cells
                                            a.    stimulated to produce 
                                                   somatostatin by HCL
                                            b.    inhibit G cells from producing 
                                                   gastrin
                                     b.    Fundic D cells
                                            a.    stimulated by gastrin to produce
                                                   somatostatin
                                            b.    inhibit ECL cells from 
                                                   producing histamine
                3.    intestinal phase
                       a.    gastric inhibitory peptide (GIP)
                             1.    inhibits gastric secretions
                             2.    inhibits gastric motility
                       b.    secretion
                              -decreases gastric secretions
                       c.    cholecystokinin
                              -inhibits stomach emptying
                       d.    enterogastric reflex
                              -inhibits stomach emptying
        B.    Pancreas
               1.    neural
                      -vagus nerve increases secretion of pancreatic 
                        enzymes
               2.    hormonal (produced by enteroendocrine cells)
                      a.    secretin
                             -stimulates pancreatic juice high in 
                               bicarbonate ions
                      b.    cholecystokinin
                             -stimulates pancreatic juice high in digestive
                               enzymes
        C.    Liver
               1.    neural
                      -vagus nerve increases bile production
               2.    chemical
                      a.    secretin stimulate bile high in bicarbonate 
                             ions
                      b.    increased blood flow to the liver increases
                             bile production
                      c.    high levels of bile salts in the blood increase
                             bile production
                      d.    cholecystokinin stimulates contraction of 
                             the walls of the gallbladder and regulates
                             the sphincter of the hepatopancreatic 
                             ampulla
        D.    Small Intestine
                1.    parasympathetic nervous system increases 
                       motility
                2.    sympathetic nervous system decreases motility
                3.    vasoactive intestinal polypeptide (VIP) 
                       stimulates production of intestinal juice
III.    Liver Functions
        A.    carbohydrate metabolism
        B.    lipid metabolism
        C.    protein metabolism
        D.    removal of drugs and hormones
        E.    excretion of bile
        F.    synthesis of bile salts
        G.    storage
        H.    phagocytosis
        I.    activation of vitamin D