Smith: Esophageal Motility

Question 1

5 steps of swallowing

Answer 1

1. elevation of the tongue
2. closure of the nasopharynx
3. UES relaxation
4. closure and protection of airway
5. pharyngeal peristalsis

Question 2

Three muscles that constrict during swallowing

Answer 2

Superior, middle, and inferior pharyngeal constrictor muscles

Question 3

Muscle that relaxes during swallowing

Answer 3

Cricopharyngeus muscle

Question 4

The UES has a resting pressure of about (blank)mmHg while the LES has a resting pressure of about (blank)mmHg

Answer 4

90mmHg; 20mmHg

Question 5

What triggers primary peristalsis?

Answer 5

swallowing in the esophagus

Question 6

The pressure wave that moves down the esophagus is coordinated with opening of the (blank), which relaxes before the propagating contraction.

Answer 6

lower esophageal sphincter (LES)

Question 7

The upper third of the esophagus is (blank), while the lower third is (blank)

Answer 7

striated; smooth

Question 8

What is the nerve plexus called between the circular and longitudinal layers?

Answer 8

myenteric plexus

Question 9

The proximal portion of the esophageal body is composed of (blank) muscle and is innervated by somatic lower motor neurons whose cell bodies are located in the (blank)

Answer 9

striated; nucleus ambiguous (NA)

Question 10

The more distal portion of the esophageal body is composed of (blank) muscle and is innervated by vagal preganglionic fibers whose cell bodies are located in the (blank)

Answer 10

smooth;dorsal motor nucleus (DMN)

Question 11

A bolus of food stimulates stretch receptors in the pharynx. The pharynx then contracts sequentially and what relaxes?

Answer 11

Upper and lower esophageal sphincters

Question 12

Vagus nerves arising from the NA release ACh directly onto the (blank) muscle where they activate nicotinic receptors on Skeletal Muscle Fibers to produce (blank).

Answer 12

skeletal; contraction

Question 13

Vagus nerves arising from the DMN release Ach where they activate Nicotinic receptors on myenteric inhibitory and excitatory motor neurons to the (blank) muscle to produce relaxation and latency followed by contraction. What causes relaxation?

Answer 13

smooth; NO

Question 14

What regulates the latency of esophageal contractions?

Answer 14

NO

Question 15

Peristalsis induced by swallowing is called (blank), while peristalsis induced by esophageal distention is called (blank)

Answer 15

primary; secondary

Question 16

Secondary peristalsis is triggered by distention in the (blank) muscle portion of the esophagus.

Answer 16

smooth

Question 17

In secondary peristalsis, contraction occurs where in relation to the bolus? This is followed by a descending pressure wave that is coordinated with (blank) opening.

Answer 17

Closer to the mouth; LES

Question 18

What does vagal stimulation do to the LES?

Answer 18

Relaxes it

Question 19

What does tetrodotoxin do?

Answer 19

Blocks the vagal stimulation to the LES; inhibits relaxation

Question 20

What is the inhibitory neurotransmitter that mediates esophageal relaxation?

Answer 20

NO

Question 21

What does hexamethonium do?

Answer 21

Blocks relaxation by blocking vagal stimulation

Question 22

What do anticholinergic drugs do to the LES?

Answer 22

Decrease LES pressure; This means that part of the LES tone is produced by cholinergic excitatory neurons releasing ACh in the LES

Question 23

Symptoms of esophageal dysfunction

Answer 23

Gastroesophageal reflux symptoms
Dysphagia
Esophageal pain

Question 24

Failure of pharyngeal propulsion and bolus clearance can be seen in this disorder

Answer 24

myasthenia gravis

Question 25

GERD is caused by the stomach contents leaking back into the (blank) due to a faulty LES

Answer 25

esophagus

Question 26

Condition in which the lining of the esophagus becomes similar to that of the lining of the stomach

Answer 26

Barrett’s esophagus

Question 27

What’s a hiatal hernia?

Answer 27

When part of the stomach pushes up through the diaphragm

Question 28

inability of the lower esophageal sphincter to open and let food pass into the stomach

Answer 28

Achalasia

Question 29

High amplitude of peristalsis; difficulty swallowing both solids and liquids

Answer 29

nutcracker esophagus