PHSI 208 Lecture Notes - Lecture 52: Esophagus, Gastroesophageal Reflux Disease, Submandibular Gland
Document Summary
Saliva is an exocrine secretion (released onto epithelial cells via a duct) Secretory cells found in clusters known as acini. , po4: serous cells = secrete water, solutes and some enzymes, mucus cells = release mucus, myoepithelial cells = it contracts to squeeze the secretions out. Glands are not identical (most saliva is produced from the submandibular gland: parotid: watery solution w/ amylase, submandibular: mixed (similar to parotid plus some mucus, sublingual: mainly mucus. Deglutition (swallowing) is a reflex that pushes a bolus of food or liquid into the esophagus. Pressure against soft palate and back of mouth activate sensory neurons going to the medulla. Medulla (swallowing center): somatic motor outputs to pharynx and upper esophagus and autonomic outputs to the lower esophagus. Contraction moves larynx up and forward, closing trachea. Upper esophageal sphincter opens (reduced motor output) Epiglottis covers airways (and breathing is inhibited)
