Physiology and Pathology of Esophagus Flashcards
what are the major arteries of the esophagus?
- thoracic branches of the aorta superiorly
- Branches of the left gastric artery inferiorly
what is the major venous drainage of the esophagus
via the azygous vein and the portal venous system via the left gastric veins
what compresses the esophagus superiorly?
larynx
what muscles are the major players in “pushing food down”
cricopharyngeus muscle and the rest of the inferior pharyngeal constrictor muscle
Sometimes an outpouching develops and food “gets stuck” – known as a
Zencker Diverticulum
what is the term for swallowing
deglutition
what are the 3 stages of deglutition?
- voluntary stage
- pharyngeal stage
- esophageal stage
what is the voluntary stage of swallowing?
- 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
what is the pharyngeal stage of swallowing?
- 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
what is the swallowing center
medulla
explain the pharyngeal phase
Food in pharynx -> afferent sensory input via vagus N. /glossopharyngeal N. -> swallowing center -> brain stem nuclei -> efferent input to pharynx
what inhibits what of the medulla, halting respiration at any point in its cycle to allow swallowing to proceed
swallowing center
respiratory center
what is the secondary peristalsis?
Result from distention of the esophagus by retained food, or by reflux of gastric contents into the esophagus
the lower esophageal sphincter normally…?
remains tonic and contricted
When a peristaltic wave passes down esophagus, what happens to the LES
receptive relaxation relaxes the LES ahead of the peristaltic wave to allow easy propulsion of food into stomach
- prevents reflux
relaxation of the LES mainly due to what?
activity of NO- and VIP-secreting branches of the vagus nerve
what is nutcracker esophagus
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
what is achalasia
incomplete LES relaxation, increased LES tone, and aperistalsis of the esophagus
what is primary achalasia
idiopathic, caused by failure of distal esophageal inhibitory neurons
what is secondary achalasia
○ 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
what esophagitis is usually a sign of immunosuppression
infectious esophagitis
what is an example of autoimmune esophagitis?
Crohn’s disease
what Esophagitis is usually distributed throughout the length of the esophagus, with primarily esosinophilic inflammation
eosinophilic esophagitis
what is reflux esophagitis?
Caused by reflux of bile and gastric acid into the esophagus
