Physiology and Pathology of Esophagus

Question 1

what are the major arteries of the esophagus?

Answer 1

• thoracic branches of the aorta superiorly
• Branches of the left gastric artery inferiorly

Question 2

what is the major venous drainage of the esophagus

Answer 2

via the azygous vein and the portal venous system via the left gastric veins

Question 3

what compresses the esophagus superiorly?

Answer 3

larynx

Question 4

what muscles are the major players in “pushing food down”

Answer 4

cricopharyngeus muscle and the rest of the inferior pharyngeal constrictor muscle

Question 5

Sometimes an outpouching develops and food “gets stuck” – known as a

Answer 5

Zencker Diverticulum

Question 6

what is the term for swallowing

Answer 6

deglutition

Question 7

what are the 3 stages of deglutition?

Answer 7

• voluntary stage
• pharyngeal stage
• esophageal stage

Question 8

what is the voluntary stage of swallowing?

Answer 8

• After chewing, food is voluntarily squeezed or rolled posteriorly into the pharynx
• By pressure of the tongue upward and backward against the palate
• From here on, swallowing becomes almost entirely automatic

Question 9

what is the pharyngeal stage of swallowing?

Answer 9

• Reflex controlled by brain stem (medulla)
  1. Food in pharynx – tactile stimulation
  2. Soft palate pulled upward
  ○ Good idea – blocks the nasal cavity so food doesn’t get shoved out your nose
  3. Palatopharyngeal folds pulled together
  ○ creates “sagittal slit” for selective action
  4. Trachea is closed (respiration inhibited)
  ○ Vocal cords approximated
  ○ Larynx raises and epiglottis covers vocal cords
  5. Relaxation of UES
  6. Peristaltic contraction of pharynx

Question 10

what is the swallowing center

Answer 10

medulla

Question 11

explain the pharyngeal phase

Answer 11

Food in pharynx -> afferent sensory input via vagus N. /glossopharyngeal N. -> swallowing center -> brain stem nuclei -> efferent input to pharynx

Question 12

what inhibits what of the medulla, halting respiration at any point in its cycle to allow swallowing to proceed

Answer 12

swallowing center
respiratory center

Question 13

what is the secondary peristalsis?

Answer 13

Result from distention of the esophagus by retained food, or by reflux of gastric contents into the esophagus

Question 14

the lower esophageal sphincter normally…?

Answer 14

remains tonic and contricted

Question 15

When a peristaltic wave passes down esophagus, what happens to the LES

Answer 15

receptive relaxation relaxes the LES ahead of the peristaltic wave to allow easy propulsion of food into stomach
- prevents reflux

Question 16

relaxation of the LES mainly due to what?

Answer 16

activity of NO- and VIP-secreting branches of the vagus nerve

Question 17

what is nutcracker esophagus

Answer 17

Visceral pain from the esophagus is well-localized, and excess distention cause relatively intense, brief chest pain
○ High-amplitude esophageal contractions
○ Outer longitudinal layer of smooth muscle contracts before the inner circular layer

Question 18

what is achalasia

Answer 18

incomplete LES relaxation, increased LES tone, and aperistalsis of the esophagus

Question 19

what is primary achalasia

Answer 19

idiopathic, caused by failure of distal esophageal inhibitory neurons

Question 20

what is secondary achalasia

Answer 20

○ diabetic autonomic neuropathy, malignancy
○ Infections (tropical countries) - Trypanosoma cruzi infection causes destruction of the myenteric plexus, failure of peristalsis, and esophageal dilatation, partial or absent lower esophageal sphincter relaxation

Question 21

what esophagitis is usually a sign of immunosuppression

Answer 21

infectious esophagitis

Question 22

what is an example of autoimmune esophagitis?

Answer 22

Crohn’s disease

Question 23

what Esophagitis is usually distributed throughout the length of the esophagus, with primarily esosinophilic inflammation

Answer 23

eosinophilic esophagitis

Question 24

what is reflux esophagitis?

Answer 24

Caused by reflux of bile and gastric acid into the esophagus

Question 25

what is Barrett’s esophagus

Answer 25

patches of red, velvety mucosa extending upward from the gastroesophageal junction that alternate with the smooth, pale normal esophageal mucosa

Question 26

what is a red flag for esophageal carcinoma

Answer 26

Heartburn that increases in severity and is accompanied by dysphagia