Digestive Page 2 (cont.)

                           c.    lipids
                           1.    simple diffusion
                                  a.    short chain fatty acids
                                  b.    long chain fatty acids
                                  c.    glycerol
                           2.    transport
                                  a.    micelle
                                  b.    chylomicron
                                  c.    lipoproteins (apoprotein + lipid)
                                         1.    HDLs
                                         2.    LDLs
                                         3.    VLDLs
                    d.    water
                           -osmosis
                    e.    electrolytes
                    f.    vitamins
             3.    Large Intestine
                    a.    water
                    b.    electrolytes
                    c.    vitamins
        F.    Defecation
II.    Regulation
        A.    Stomach - gastric secretion, motility and emptying
                1.    cephalic phase
                       a.    vagus nerve (parasympathetic) increases 
                              gastric secretions and gastric motility
                       b.    sympathetic stimulation caused by emotions
                              decreases gastric secretions and motility
                2.    gastric phase
                       a.    neural negative feedback
                              1.    input
                                     a.    stretch receptors
                                     b.    chemoreceptors
                              2.    output via parasympathetic nervous 
                                     system - vagus nerve secreting 
                                     acetylcholine that binds to
                                     muscarinic receptors
                                     a.    increases peristalsis
                                     b.    increases gastric juice
                                            1.    increases the release of 
                                                   histamine from the ECL cell
                                            2.    increases the release of HCl 
                                                   from the parietal cell
                                            3.    increases the release of gastrin 
                                                   from the G cell
                              3.    output via sympathetic nervous system -
                                     secreting epinephrine that binds to beta
                                     receptors
                                     a.    increases histamine release by ECL 
                                            cells
                              4.    the neurotransmitter Gastrin-releasing 
                                     peptide (GRP) increases gastrin from 
                                     G cells
                              5.    the neurotransmitter Calcitonin 
                                     gene-related peptide(CGRP) increases 
                                     somatostatin from D cells
                       b.    hormonal
                              1.    gastrin (from G cells in the pyloric 
                                     antrum)
                                     a.    Factors effecting gastrin release
                                           1.    Increasing release
                                                  a.    amino acids in the gastric 
                                                         lumen
                                           2.    Decreasing release
                                                  a.    pH less than 3.0 in the 
                                                         gastric lumen
                                     b.    Functions of gastrin
                                           1.    increases the number of ECL 
                                                  cells 
                                           2.    stimulates secretion of HCl
                                                  a.    indirectly- increases 
                                                         histamine synthesis and 
                                                         release from ECL
                                                         cells by binding to 
                                                         CCK-B receptors
                                                  b.    directly- increases HCL 
                                                         release from parietal cells 
                                                         by binding to
                                                         CCK-B receptors
                                           3.    indirectly inhibits secretion of 
                                                  HCL by increasing somatostatin 
                                                  release from D cells
                                           4.    causes contraction of lower 
                                                  esophageal sphincter
                                           5.    increases stomach motility
                                           6.    relaxes pyloric sphincter
                              2.    histamine (from enterochromaffin-like 
                                     (ECL) cells in the fundus)
                                     

     cont.