Cephalic phase • Brain activated by smell, sight, thought, taste of food. • Neurons to salivary glands and gastric glands/stomach muscles • Autonomic nervous system
Gastric phase • Stimulus: food in stomach • Neural: • Stretch receptors activated. Impulse to neurons in submucosa. Triggers: • gastric gland production and causes peristalsis. • Hormonal: • Food triggers release of gastrin (hormone). Goes in blood. Triggers: • gastric gland juices, • sphincter to prevent acid-reflux, • stomach muscles • relaxes lower stomach sphincter.
Intestinal phase • Stimulus: food in intestines • Neural: stretch receptors to medulla oblongata. Sympathetic nerves to stomach cause: • decreased stomach movement and increase contraction of pyloric – bottom - sphincter (delays stomach emptying) • Hormonal: • Cholecystokinin (CCK): stimulates pancreatic juice/squeezes gallbladder