Saliva and Swallowing

Saliva

99.5% water and 0.5 % protein, starts carbohydrate digestion, washes away food particles, neutralizes acids

Parasympathetic relation to saliva

low-level of secretion

simple salivary reflex

chemoreceptor and pressure receptors in the oral cavity respond to the presence of food and activate salivary centers

Salivary center

in the medulla

Parasympathetic Salivary reflex

abundant watery saliva rich in enzymes

Sympathetic Salivary reflex

produces small amounts of thick, stringy mucus-rich saliva

Esophagus

leads from pharynx to stomach, mucous glands are scattered throughout the submucosa (moisten and lubricates the inner lining)

Pharyngoesophageal sphincter

keeps the entrance closed to prevent large volumes of air from entering the esophagus and stomach during breathing

Gastroesophageal Sphincter

prevents reflux of gastric contents

What waves push food through

peristaltic waves

Oropharyngeal stage

moves bolus from mouth to esophagus