1 F: The Esophagus & Deglutition (swallowing) Flashcards
Describe the gross anatomy of the esophagus
Flattened muscular tube of 18-26 cm from upper sphincter to lower sphincter.
What happens between swallows?
The esophagus is collapsed but the lumen can distend to approx. 2 cm in the anterior-posterior dimension & up to 3 cm laterally to accommodate a swallowed BOLUS
What does the esophagus connect?
Connects the pharynx to the stomach
Where does the Esophagus begin?
Begins at the neck at the Pharyngoesophageal junction (C5-6 interspace of the cricoid cartilage)
Where does the esophagus descend?
Descends anteriorly to the vertebral column through the superior and posterior mediastinum.
After traversing the diaphragm at the diaphragmatic hiatus (T10 vertebral level) where does it extend?
It extends thru the gastroesophageal junction to end at the orifice of the cardia of the stomach (T11 vertebral level)
Describe the histology of the esophagus
Non-keratinized stratified squamous
Why is the epithelial continuity critical for function?
A breach in the epithelium creates an ulcer
What does the Esophageal submucosa include? What does this help do?
Includes scattered esophageal glands.
**This provides mucus for lubricating the passage of food down the esophagus, augmenting that role of the salivary glands
What is the wall of the esophagus made up of?
1) The mucosa
2) Submucosa
3) Muscularis
Unlike the rest of the GI tract, the esophagus has what?
***Unlike the rest of the GI tract, the esophagus has NO TRUE SEROSAL OUTER LAYER, but is covered by a think & poorly defined layer of CT
In the esophagus, the submucosal vascular plexus includes what?
Especially large venous spaces (that drains away from the esophagus)
What does the Collateral of the L. Gastric Vein (a branch of the portal vein) receive venous drainage from?
From the mid and lower esophagus, plus from the submucosal venous plexus
Where are most of the veins in the esophagus found?
In the submucosal layer
What are Esophageal VARICES?
(“Varicose veins of the esophagus”)
-The submucosal venous spaces, along w/ all the other “draining” veins of the mid to lower esophagus may enlarge into esophageal varices.
In an Endoscopic image of perhaps a Cirrhotic patient w/ (portal hypertension), what is prominent?
Esophageal varices w/ red wale spots on the surface
***indicates a high risk of bleeding
In what case is Esophageal VARICES common?
Especially with portal hypertension (an increase in pressure in the portal vein, due to liver cirrhosis)
What is the risk with such varices?
They carry a substantial risk of rupture w/ fatal bleeding into the esophageal lumen
What does swallowing (deglutition) consist of ?
1) Oral or voluntary phase
2) Pharyngeal phase (involuntary)
3) Esophageal phase (involuntary)
What is swallowing initiated by?
Voluntary action of collecting the oral contents on the tongue & propelling them backward to the pharynx (oral phase)
What does the pharyngeal phase start with?
With a wave of involuntary contraction in the pharyngeal muscles that pushes the material into the esophagus, as the upper esophageal sphincter (UES) RELAXES and OPENS
What is part of the reflex response ?
Inhibition of respiration and stimulation of glottic closure
Why does the material tilt the epiglottis backward & down over the closed glottis ?
For further protection from food entering the respiratory airways
What phase is involved once food enters the esophagus, and peristalsis takes over
Esophageal phase
What does Esophageal peristalsis involve?
A progressive wave of ring-like smooth contractions that propels for down tot the lower esophageal sphincter (LES)
What occurs once triggered by swallowing?
Esophageal peristalsis will occur whether or not food is present
***although that presence of food will intensify the contractions.
What occurs if the primary peristaltic wave fails to move food into the stomach?
The persistence of the food bolus in the esophagus will set off secondary peristaltic wavies to complete the job
The LES, like most sphincters is tonically ___________
contracted
How can the tonic contraction of the LES be influenced?
By either relaxing (opening) or by contracting further
What is Achalasia?
The failure of the LES to relax causing swallowed food difficulty passing into the stomach, and the esophagus above the LES becomes enlarged
What can happen if LES becomes enlarged and food isn’t passed to stomach directly?
One or several meals may lodge in the esophagus and pass slowly into the stomach over time.
***There is danger of aspiration of esophageal contents into the lungs when person lies down
What is Gastroesophageal reflux disease (GERD) ?
When various agents have been showed to decrease LES pressure, which decreases it’s closing strength.
Allowing reflux of acidic gastric contents into the esophagus
What can also contribute to reflux ?
Delayed gastric emptying may contribute by increasing gastric VOLUME and PRESSURE with greater chance for reflux
What is an example of this common condition and what can it lead to ?
Heartburn and esophagitis
-Leads to ulceration and structure of the esophagus due to scarring
What does current research indicate about GERD?
That there may be a STRONG causal relationship between GERND & Esophageal Adenocarcinoma
What are the agents that have been demonstrated to diminish the closing strength of the LES?
1) Fatty foods 2) chocolate 3) ethanol 4) caffeine 5) peppermint 6) spicy foods 7) citrus fruits and juices 8) smoking 9) steroidal based oral contraceptives
Complications can result from persistent reflux producing a cycle of mucosal damage that causes what?
EDEMA and erosion of the luminal surface
What does these complications include strictures and a conditions called_________
Barrett’s esophagus
Strictures are caused by ?
a combination of scar tissue, spasm, and EDEMA
What can stricutres do to the esophagus?
Produce narrowing of the esophagus and cause DYSPHAGIA (difficulty swallowing) when the lumen is sufficiently constricted
What do patients with Dysphagia complain of ?
Choking, coughing, or an abnormal sensation of food sticking in that back of the throat or upper chest when they swallow.
What is odynophagia?
Swallowing that is painful
In a normal lower esophageal sphincter should it initially be closed or open?
Closed!
(With Barrett’s mucosa it can’t close properly and presents with redder pigment. Refereed to as “tongue of Barrett’s esophagus”
What is Barrett’s esophagus characterized by?
A repair process in which the squamous mucosa that normally lines the esophagus is gradually replaced by COLUMNAR epithelium (METAPLASIA)
**The replacement resembles the stomach and intestines
What is it associated with?
Increased risk of developing esophageal cancer
