Esophagus physiology

Question 1

How many nuclei do smooth muscle cells have?

Answer 1

One

Question 2

Do GI smooth muscle cells have sarcomeres?

Answer 2

No

Question 3

This type of muscle cell does not have sarcomeres

Answer 3

GI smooth muscle

Question 4

This type of muscle cell acts as a unitary, in which gap junctions permit coordinated contraction

Answer 4

GI smooth muscle

Question 5

This type of muscle cell does not need innervation for contraction

Answer 5

GI Smooth muscle
(stimulus is stretch)

Question 6

This movement in the GI tract increases surface area

Answer 6

Mixing movements

Question 7

GI propulsive movements requires this to be intact

Answer 7

Myenteric plexus

Question 8

During peristalsis, excitation of motor neurons (Ach, substance P) contracts this muscle

Answer 8

Circular smooth muscle

Question 9

During peristalsis, excitation of inhibitory motor neurons (NO, VIP) relaxes this muscle

Answer 9

Longitudinal smooth muscle

Question 10

Peristalsis mostly occurs by the action of this smooth muscle

Answer 10

Circular muscle

(Longitudinal muscle shortens the distance between points - not a significant role in peristalsis)

Question 11

This type of muscle in the esophagus requires neural input

Answer 11

Striated (skeletal) muscle

Question 12

CNS is required for peristalsis in this part of the esophagus

Answer 12

Upper and middle 2/3
(due to skeletal muscle required CNS)

Question 13

CNS is not required for peristalsis in this part of the esophagus
Myenteric plexus is instead requires

Answer 13

Lower 1/3
(due to being composed of smooth muscle)

Question 14

During swallowing, does the movement of food to the pharynx increase or decrease pressure at the Upper esophageal sphincter?

Answer 14

Increases

(This primary peristaltic wave causes the UES to open and food moves into esophagus)

Question 15

During swallowing, as a bolus of food reaches the lower esophageal sphincter, does it relax or contract to allow food into the stomach?

Answer 15

Relaxes

Question 16

The nucleus ambiguus innervates this part of the esophagus

Answer 16

Skeletal muscle and mixed areas
(Upper and middle 2/3)

Question 17

The dorsal motor nucleus innervates this part of the esophagus

Answer 17

Smooth muscle
(lower 1/3)

Question 18

Does sympathetic ganglia play a role in GI motility?

Answer 18

No - mostly a sensory role, also in blood flow

Question 19

Is peristalsis in the striated muscle portion of the esophagus a gravity event?

Answer 19

NO - is due to circular muscle action

Question 20

Does the dorsal motor nucleus play a role in motility of smooth muscle?

Answer 20

No - CNS is NOT required for peristalsis in smooth muscle portion of esophagus

Question 21

The myenteric plexus is key for peristalsis in this part of the esophagus

Answer 21

Smooth muscle part (lower 1/3)

Question 22

Is peristalsis in smooth muscle of the esophagus a gravity event?

Answer 22

No - mostly a circular muscle event

Question 23

Is esophageal peristalsis in the striated or smooth muscle portion a circular muscle event?

Answer 23

BOTH

Question 24

Latency in contraction of circular muscle is related to release of this molecule

Answer 24

NO (nitric oxide)

Question 25

Duration (on) response of longitudinal muscle is due to this molecule

Answer 25

Acetylcholine

Question 26

Relaxation of the lower esophageal sphincter (during peristalsis) is due to this compound, via the myenteric plexus

Answer 26

Nitric oxide (NO)

Question 27

Does the Myenteric plexus release excitatory or inhibitory neurotransmitters?

Answer 27

Both

Question 28

Propagation of peristaltic wave is related to this gradient

Answer 28

Latency gradient

Question 29

Is the lower esophageal sphincter typically under low or high pressure?

Answer 29

High

Question 30

Relaxation of the lower esophageal sphincter can be inhibited by compound

Answer 30

Tetrodotoxin (TTX)

Question 31

Is the opening or closing of the lower esophageal sphincter due to neural activity (via nitric oxide)?

Answer 31

Opening

Question 32

Is the opening or closing of the lower esophageal sphincter due to intrinsic activity of smooth muscle?

Answer 32

Closing

Question 33

In achalasia, there is damage to this structure, resulting in loss of nitric oxide (and subsequent inability to relax LES)

Answer 33

Myenteric plexus

Question 34

This pathology is sometimes also called hypertensive peristalsis Is very painful, hard to localize (visceral) Angina-like pain

Answer 34

Diffuse esophageal spasm

Question 35

Nutcracker esophagus occurs at this part of the esophagus

Answer 35

Distal (smooth muscle portion)

Question 36

Diffuse esophageal spasm, as well as Nutcracker esophagus, can be treated with these 3 types of drugs

Answer 36

Calcium channel blockers Nitroglycerin Botox

Question 37

Regurgitated food from this part of the body will have a tart taste

Answer 37

Stomach (due to acid)

Question 38

Regurgitated food from this part of the body will have a putrid taste

Answer 38

Esophagus (as seen in GERD)

Question 39

This condition may present with esophageal distention, dysphagia, vomiting, and aspiration pneumonia

Answer 39

Achalasia

Question 40

Is diffuse esophageal spasm painful?

Answer 40

YES - angina-like pain; mimics an MI

Question 41

Is Achalasia painful?

Answer 41

Not usually

Question 42

Metaplastic (abnormal) change in mucosa of esophagus due to adaptation to acid reflux Occurs in many patients with GERD, starting at gastroesophageal junction Increases the propensity for esophageal adenocarcinoma

Answer 42

Barrett's esophagus