Motor innervation of tongue = cn xii, hypoglossal nerve. Sensory innervation is different saliva secretion from 3 salivary glands (exocrine glands that open contents into ducts) stomach is in luq, pancreas is behind it liver is in ruq. Gallbladder is below liver, releases bile to emulsify fat in duodenum function of the spleen = accumulates dead rbcs and forms bilirubin (also by liver) Precursor of bilirubin is biliverdin wall of gi tract has smooth muscle intestines has longitudinal and circular. Enteric nervous system = plexus of meissner and auerbach. These 2 plexus control and innervate smooth muscle of gi, and control peristalsis movement/motility of gi. -parasymp/vagus n. accelerates peristalsis and increases endocrine hormone secretion from gi glands (ach) -symp has negative effect on gi, decreases peristalsis, decreases secretion of endocrine hormones from gi glands. Histologic structure: mucus membrane, muscularis mucosa, muscle layer, circular muscle, longitudinal muscle, serosa external layer that covers tube of gi.