Lesson #3: The Esophagus and Deglutition

Question 1

The Esophagus

Answer 1

A long tube that connects the oral cavity to
the stomach.

Uses waves of muscular contractions called
peristalsis to move the food down to the
stomach.

Question 2

Deglutition – Stage 1: Oral Phase

Answer 2

In the oral phase, the food is mechanically digested by the teeth.

The tongue mixes the mechanically digested mass with saliva
from the salivary glands to form a bolus.

The tongue creates a downward slope to move the bolus
pharynx.

Question 3

Deglutition – Stage 2:
Pharyngeal Phase

Answer 3

The pharynx contains nerves
that directly connect to the
central nervous system. The
presence of the bolus
stimulates these nerves.

The vagus nerve is responsible
for the three activities in this
area.
The nasopharynx is blocked by the uvula and the pulling up of the soft
palate.

The vocal cords are pulled together and the epiglottis falls over the
trachea.

The larynx is elevated and moved forward, muscles in the back of the
throat contract to lead the bolus towards the esophagus. The upper
esophageal sphincter relaxes to allow the bolus to enter the
esophagus.

Question 4

Deglutition – Stage 3: Esophageal
Phase

Answer 4

The esophagus is a muscular tube that contracts to move the bolus down
towards the stomach.

This peristalsis begins in the pharynx and continues in the esophagus.

The lower esophageal sphincter (cardiac sphincter) relaxes to allow the
bolus to enter the stomach.