Histology of the Esophagus

Question 1

What are the muscular layers of the esophagus?

Answer 1

1. Longitudinal (outer)
2. Circular (inner)

Question 2

What are the three regions of musculature in the esophagus?

Answer 2

1. Striated Muscle:
Pharynx
Upper Esophageal Sphincter
Upper 1/3

2. Mixed Striated and Smooth Muscle:
Middle 1/3

3. Smooth Muscle:
Lower 1/3
Lower Esophageal Sphincter

Question 3

What are the histological layers of the esohpagus?

Answer 3

1. Stratified squamous epithelium (non-keratinized)
2. Lamina propria
3. Muscularis Mucosa
4. Esophageal glands
5. Submucosa
6. Circular muscle
7. Longitudinal muscle

(Lumen –> Outer layer)

Question 4

What are the sources of innervation of the esophagus?

Answer 4

CNS and Extrinsic

Intrinsic enteric nervous system (Auerbach) plexus
(cholenergic and norandrenergic)

Question 5

What are the phases of swallowing?

Answer 5

Voluntary
Pharyngeal
Esophageal

Question 6

What is normal esophageal transit time?

Answer 6

5-10 seconds

peristolsis is important only for solids when upright

Question 7

What is secondary peristalsis?

Answer 7

When something gets stuck on the way down

Originates in the esophagus and triggered by distention

Will continue until the blockage clears