Week 2: Esophageal motility

Question 1

What is the main function of the esophagus?

Answer 1

transit of food to the stomach

Trick is

• dont choke
• dont aspirate food into the trachea
• don’t aspirate air into the gut

Question 2

Describe esophageal manometry

Answer 2

UES - upper esophageal sphincter

LES - lower esophageal sphincter

At the UES you are above atmospheric pressure
as you go lower the pressure decreases but at the diaphragm above atmo pressure

Question 3

esophageal manometry during a swallow

Answer 3

initially open and then snap shut

Pressure wave going down but the bottom is open and gravity can take bolus down before even the pressure wave gets there depending on the viscosity of what is being swallowed, this is why liquids can be swallowed faster than solids

stomach relaxes to prepare for the bolus to enter

Question 4

Functions of the esophagus

4 listed

Answer 4

Question 5

Reflexes involved in the initiation of swallowing

2 listed

Answer 5

Question 6

Describe the oral or voluntary phase of swallowing

Answer 6

Moves food into the pharynx

Question 7

Describe the pharyngeal phase of swallowing

Answer 7

• Larynx moves forward, epiglottis prevents entry into trachea and helps open UES
• soft palate prevents reflux into nasopharynx, provides passage into pharynx

Question 8

Pharyngeal phase of swallowing

Answer 8

involuntarily and neuronally mediated through Vagal efferents

brain also turns of respiration which picks back up as soon as the UES closes

Question 9

Describe UES regulation

Answer 9

• tonically contracted between swallows
• relaxes during swallows

Question 10

Muscle types in the esophagus

Answer 10

Question 11

Describe the muscles and nerves of the pharynx and upper esophagus

Answer 11

Question 12

What drives peristalsis

Answer 12

entirely done by neurons contained in the wall of the gut in between the longitudinal and circular muscle fibers

Question 13

IDentify structure and components

Answer 13

Question 14

Locations of the principal networks of enteric neurons

Answer 14

• Myenteric plexus
• Submucous plexus

Question 15

Identify structures and components

Answer 15

Question 16

Describe peristalsis mechanism

Answer 16

You get a peristaltic contraction behind the bolus and a relaxation in front of the bolus which is in tune with the size, shape and chemistry of the bolus without any input from the brain through the combination of sensory neurons and efferent neurons of the enteric nervous system

Question 17

Describe the peristaltic reflex

Answer 17

sensory neurons sense the bolus and interneurons to coordinate contraction and relaxation of motor neurons to move the bolus as needed

Question 18

Regulation of GI smooth muscle peristalsis

Answer 18

bolus hits villi activating sensory neurons and data is transmitted through the interneurons to get a coordinated contraction and relaxation behind and in front of the bolus respectively

Question 19

Muscles and nerves of the pharynx and upper esophagus

Answer 19

Question 20

Peristalsis transmissions speeds

Answer 20

Question 21

M2 receptor second messenger

Answer 21

inhibition of adenylate cyclase

Activation of K+ channels

Question 22

M2 receptor targets

Answer 22

Heart

Question 23

M2 receptor effects

Answer 23

Inhibition

Question 24

M3 receptor second messenger

Answer 24

Stimulation of phospholipase C

Question 25

M3 receptor targets 2 listed

Answer 25

* smooth muscle * secretory glands

Question 26

M3 receptor effects 2 listed

Answer 26

* Contraction (smooth muscle) * secretion (secretory glands)

Question 27

Cardiac muscle stimulation

Answer 27

increase adenylate cyclase

Question 28

Cardiac muscle inhibition

Answer 28

decrease adenylate cyclase

Question 29

Smooth muscle stimulation

Answer 29

Increase phospholipase C

Question 30

Smooth muscle inhibition

Answer 30

Increase adenylate cyclase

Question 31

Glandular stimulation

Answer 31

Increase phospholipase C

Question 32

Inhibition of adenylate cyclase

Answer 32

M2 Gi coupled receptor

Question 33

Activation of phospholipse C pathway

Answer 33

Question 34

Excitatory neurotransmission to GI smooth muscle

Answer 34

Question 35

Inhibitory neurotransmission to GI smooth muscle

Answer 35

Question 36

LES regulation

Answer 36

Question 37

Describe the overall mechanism of primary peristalsis

Answer 37

Question 38

Describe the overall mechanism of secondary peristalsis

Answer 38

Question 39

Question

Answer 39

C. Activation of M3 and M2 receptors on smooth muscle cells

Question 40

Disorders of esophageal motility 3 listed

Answer 40

* Stroke * Achalasia * Reflux

Question 41

Summary of esophageal motility

Answer 41

Question 42

How common is induced dysphagia from stroke?

Answer 42

common - up to 65% of stroke patients

Question 43

Swallowing phase effected by stroke-induced dysphagia

Answer 43

Loss of coordination of pharyngeal phase

Question 44

Complications of stroke-induced dysphagia

Answer 44

* Pneumonia * poor nutrition

Question 45

Treatment of Stroke-induced dysphagia

Answer 45

* Physical therapy * Modify texture of foods

Question 46

What is Achalasia?

Answer 46

Loss of coordination of smooth muscle peristalsis

Question 47

Swallowing phase effected by Achalasia

Answer 47

Lack of complete opening of LES so food remains in the esophagus leading to pain and regurgitation

Question 48

Treatment of Achalasia

Answer 48

* Smooth muscle relaxants * Surgery

Question 49

Cause of loss of esophageal motility due to Reflux

Answer 49

Low resting pressure in LES

Question 50

Phase of swallowing effected by reflux

Answer 50

Poor secondary peristalsis

Question 51

Treatment of reflux induced loss of esophageal motility

Answer 51

* Symptomatic treatment - acid reduction * Surgical treatment - Strengthen LES