5. Esophageal Motility Flashcards
Esophagus is a hollow muscular tube that traverses cervical, thoracic and abdominal
compartments reaching _____in length and _____ in dimension
18-26 cm
2-3 cm expansion
Esophageal wall structure consists of four layers:
mucosa, submucosa, muscularis prorpia and adventitia:
upper quarter of the esophagus and upper esophageal sphincter (UES) are composed of
striated muscle
lower half of esophagus, along with intrinsic lower esophageal sphincter (LES) are
composed of
smooth muscle.
What structure reinforces the LES
Crural diaphragm
coordinated and propulsive
sequential contraction of the
esophageal muscle
peristalsis
• Primary peristalsis occurs in concert with appropriately timed relaxation of
the upperand lower esophageal sphincters.
How do you record peristalsis in the esophagus?
Primary peristalsis as recorded by an
intraluminal manometry catheter
triggered by swallow and associated with pharyngeal contraction and
UES relaxation
Esophageal Primary Peristalsis
Describe the features of secondary peristalsis
triggered by esophageal distention
Contraction starts PROXIMAL to distention
What controls the intrinsic and extrinsic peristalsis?
Intrinsic: Enteric neural plexus
Extrisinic: vagus
Swallowing (a) evokes a peristaltic wave of contraction that migrates
smoothly from the striated to smooth muscle esophagus. Simultaneous
electrical activation of all______ efferent neurons produces
________ in the striated muscle esophagus, and in the smooth muscle segment a ________ is induced.
vagal
simultaneous contractions
peristaltic wave
intrinsic neurons activated by vagal efferent nerve stimulation are capable of evoking a peristaltic contraction without the need for
centrally mediated sequencing.
Proximal esophageal striaghted muscle peristalsis we have a motor end plate and an action potetial… what occurs in the action potential
Ca 2+ Release mainly from sarcoplasmic reticulum via Ttubules
in the PROXIMAL part of the esophagus; Sequence of peristalsis is generated by the swallowing __________ of brainstem
“central pattern generator”
Distal Esophageal Smooth Muscle Peristalsis is generated by:
varicose nerve endings and gap jnxs with Ca+ influx from outside (unlike Ttubs in the proximal esophagus)
In distal esophageal smooth muscle, Peristalsis in smooth
muscle is physiologically regulated as
“a wave of inhibition followed by a wave of excitation”
Vagal efferent synapse on excitatory adn inhibitory myenteric mortor neurosns, what is the excitatory one and what happens?
Excitatory motor neurons: Predominantly Acetylcholine –>
Ca2+ release –> depolarization –> second messenger pathways
(substance P)
What the is vagal inhibitory neuron and it’s action
Inhibitory motor neurons:
Predominantly Nitric oxide –>cGMP dependent pathway –> inhibition of
Ca2+ entry–> hyperpolarization
• (Vasoactive intestinal peptide)
Described as: “Sticks”,“Caught”,“hangs up”
• Most specific esophageal symptom
• Almost always organic and different from globus sensation (always a lump in throat)
Dysphagia
Pain during swallow and bolus transit
Odynophagia
Dysphagia in what location?
sticks or hangs up after swallow
may or may not have chest pain
Esophageal dysphagia
Dysphagia when you have difficulty swallowing and cough or choke w/ nasal regurg
pharyngeal dysphagia
