Upper GI Flashcards
What are the four histological layers of the GI tract?
Mucosa
Submucosa
Muscularis externa
Serosa
What type of epithelium are the proximal and distal ends of the GI tract?
Stratified squamous, nonkeratinized
What type of epithelium is the majority of the GI tract?
Simple columnar
What are the two nerve plexi of the GI system?
Submucosal (Meissner’s)
Myenteric (Auerbach’s)
What is the function of the submucosal (Meissner’s) plexus? Parasympathetic or sympathetic innervation?
Regulate the activity of the muscularis mucosae and secretion of glands/blood flow
Parasympathetic
What is the function of the Myenteric (Auerbach’s) plexus? Parasympathetic or sympathetic innervation?
Regulates the activity of the muscularis externa
What is the Z-line in the distal esophagus?
Where stratified squamous epithelium meets stratified columnar (esophagus to cardiac region of the stomach, just distal to the esophageal sphincter)
What is the outermost layer of the mucosae?
Muscularis mucosae
Where are lymphatics found in the GI Tract layers?
Submucosa
What are the layers of the GI tract?
Mucosa
Submucosa
Muscularis externa (propria)
What is the outermost layer of the GI tract? What is the exception to this?
Serosa
Esophagus has an outer coat of epithelium, not a serosa
Where are glands found in the GI tract? What are the two exceptions to this?
Submucosa
What does the myenteric plexus lie between?
Internal circular and external longitudinal muscularis layers
What is Barrett’s esophagus?
Change of the distal esophagus from stratified squamous to simple columnar with goblet cells. This is precancerous (adenocarcinoma)
What is the stain that is used to identify goblet cells? What is this staining?
Alcian blue stains the acidic mucosubstances secreted by the goblet cells
What third of the esophagus is most likely to harbor an adenocarcinoma?
distal third
What third of the esophagus is most likely to harbor a squamous cell carcinoma?
Middle third
How do you determine the staging of esophageal stratified squamous cell carcinoma?
How far the squamous cells infiltrate the esophagus
Who is particularly at risk of squamous cell carcinoma?
AA
EtOH abuse
Men
What type of esophageal cancer would most likely cause hoarseness: SCC or adenocarcinoma? Why?
SCC–can penetrate the wall of the esophagus, and hit the recurrent laryngeal nerve (from CN X)
What are the four anatomical esophageal constrictions?
- upper esophageal sphincter
- Aortic arch crosses
- Left bronchus
- Esophageal hiatus at the diaphragm
What vertebral level is the diaphragm at?
T10
What is pill esophagitis?
When patients have difficulty swallowing pills secondary to lower muscles tone of the esophagus
Why is SCC more common in the middle third?
Surrounded by strictures, possibly, but not totally known
What is the common site for diverticula in the esophagus?
Gap between oblique fibers of the thyropharyngeus and the Cricopharyngeus muscle
(Killian’s triangle)
What are pharyngoesophageal diverticulum?
Penetration of the mucosa + submucosa through the walls of the pharynx
What are the symptoms of pharyngeal esophageal diverticulum?
Extreme halitosis
What is the arterial supply of the esophagus?
Esophageal branches of the aorta
What is the blood supply to the upper part of the esophagus?
Inferior thyroid artery
What is achalasia?
Loss of the inhibitory neurons in the esophagus (which secrete NO and VIP).
“Crow’s beak” appearance of the esophagus = ?
Achalasia
Lymph flow in the esophagus tends to move where? (what direction, and in what layer)
Superiorly/inferiorly in the lamina propria, submucosa, and muscularis externa
Lymph flow in the colon go where?
Laterally in the submucosal lymph channels
A tumor in the superior esophagus tends to spread where?
Cervical lymph nodes, IJV, subcarina nodes
A tumor in the inferior esophagus tends to spread where?
Abdominal cavity
Celiac and cardiac nodes
What is the main lymph node in the abdomen?
Cisterna chyli
What is a chylothorax?
Damage to the left thoracic duct may result in back up of lymph into the abdomen
What are the G cells of the stomach?
Gastrin producing cells that stimulate parietal cells to secrete HCl
What is the role of the parietal cells?
Secrete HCl
Where are G cells particularly found?
Pylorus of the stomach
What layers do ulcers penetrate through?
To the muscularis propria
Where are most ulcers found in the stomach?
Lesser curvature of the stomach
What is Zollinger-Ellison syndrome?
Tumors of gastrin producing cells in the gastrinoma triangle
What are the vertices of the gastrinoma triangle?
- Junction of the cystic duct and common hepatic duct
- Junction of the neck and body of the pancreas
- Junction of the 2nd and 3rd parts of the duodenum
What happens to the rugae in the stomach with zollinger-ellison syndrome?
Expanded due to increase in parietal cell mass
What are the 6 primary arteries of the stomach?
- Right gastric
- Left gastric
- R gastro-omental
- L gastro-omental
- Gastroduodenal
- Splenic
What is the potential problem with ligation of the left gastric artery?
Need to make sure that there is not a left hepatic artery is not a branch of the left gastric
What are the three branches of the celiac artery?
Common hepatic
Splenic
Left gastric
What are the two muscles that comprise the inferior pharyngeal constrictor? Name them superior to inferior.
Thyropharyngeus
Cricopharyngeus
What is Killian’s triangle, and what is its significance?
Area between the thyropharyngeus and the cricopharyngeus, and is a potential site of weakness for diverticula or rupture during endoscopy
What are Zenker’s diverticula?
Pharyngoesophageal diverticula in Killian’s triangle
What is the area of the stomach that is removed in refractory PUD? Why?
The pyloric antrum
Where the gastrin cells are