Chapter 90: Esophagus

Question 1

What is the outer layer of the esophagus called?

Answer 1

The adventitia

Question 2

What are the four layers of the esophagus?

Answer 2

Adventitia
Muscularis
Submucosa
Mucosa

Question 3

For which species is the caudal 1/3 of the esophagus smooth muscle?

Answer 3

Cats

Question 4

What are the three phases of swallowing?

Answer 4

Oropharyngeal
Esophageal
Gastroesophageal

Question 5

What cranial nerves are involved in the oropharyngeal phase of swallowing?

Answer 5

5,7,9,10,12
Trigeminal
Facial
Glossopharyngeal
Vagus
Hypoglossal

Question 6

What are the three portions of the oropharyngeal phase of swallowing?

Answer 6

Oral: bolus formed + delivered to pharynx
Pharyngeal:1st involuntary step, deliver to oropharynx, nasopharynx/larynx closed, pharyngeal constrictors push to cricopharynx
Cricopharyngeal: constrictors relax and bolus passes to cranial esophagus.

Question 7

What two muscles are part of the “upper esophageal sphincter”?

Answer 7

Cricopharyngeus and thyropharyngeus, NOT a true sphincter

Question 8

What is the transit time of the esophagus?

Answer 8

Liquid 2.58cm/sec and Kibble 4.44cm/sec in sternal
*type of meal and position affects time - sternal more normal contractions than right lateral, right lateral took longer.

Question 9

The blood supply to the esophagus is what type?

Answer 9

Segmental

Question 10

True or false: Esophagus heals slower than other GIT?

Answer 10

True - be cautious if need to cut it, consider vasculrarized patches and avoid damage to mural vessels. Divert food via G-tube or other method while healing.