Communication with nasal cavity behind soft palate. Floor is muscular tongue. Swallowing involves co-ordinated activity of tongue, soft palate pharynx and oesophagus. After this the process is reflex. The tongue blocks the mouth, soft palate closes off the nose and the larynx rises so that the epiglottis closes off the trachea.
Food thus moves into the pharynx and onwards by peristalsis aided by gravity.
If we try to talk whilst swallowing food may enter the respiratory passages and a cough reflex expels the bolus. Basic tissue layers of the gut are 1. mucosa. Innermost, moist lining membrane. Soft connective tissue layer, blood vessels, nerves, lymphatics 3. muscularis externa. Typically circular inner layer, longitudinal outer layer of smooth muscle 4.