EXAM #1: UPPER GI ANATOMY Flashcards
What are the four layers of the GI tube?
1) Mucosa
2) Submucosa
3) Muscularis externa/ propria
4) Serosa
What are the four layers of the mucosa?
- Epithelium is in contact with chyme
- Basal lamina
- Lamina propria
- Muscularis mucosae
What are the two layers of the muscularis externa/ propria?
- Inner circular
- Outer longitudinal
Where in the mucosa are lymphatics, nerves, blood vessels, and glands located?
Lamina propria
In what two segments of the GI tube are glands in the submucosa?
Esophagus
Duodenum
What are the two plexus of the GI tube?
- Submucosal–inner
- Myenteric–outer
What is the eponym for the Submucosal plexus?
Meissner’s plexus
What is the eponym for the Myenteric plexus?
Auerbach’s plexus
What is the function of the submucosal plexus?
Ion and fluid movement
What is the function of Meissner’s plexus?
Motility
What is the normal type of epithelium in the esophagus? Stomach? Describe their appearance.
Esophagus= Nonkeratinized stratified squamous epithelium (pale)
Stomach= Non-ciliated simple columnar epithelium with goblet cells(red/ tongue-like)
What is the name of the transition between the epithelium of the esophagus and stomach?
Z-line
What is Barrett’s esophagus?
Metaplasia in the distal esophagus with simple columnar epithelium with goblet cells in response to GERD
How is Barret’s Esophagus diagnosed?
ALCAIN BLUE staining
- Goblet cells in esophagus will produce mucous
- alcain blue stains mucous
What cancer are patients with Barett’s Esophagus at risk for?
Adenocarcinoma
What third of the esophagus is most likely to harbor an adenocarcinoma?
Distal 1/3
What third of the esophagus is most likely to harbor a squamous cell carcinoma (SCC)?
Middle 1/3
What patient populations are at risk for stratified squamous cell carcinoma?
Males
African Americans
Smokers
Drinkers
What type of esophageal cancer is most likely to cause hoarseness? Why?
SCC
**Middle 1/3 of the esophagus is in close proximity to the recurrent laryngeal nerve of the vagus (innervates the larynx) ***
Generally, how is SCC staged?
The deeper the penetration of the esophageal walls, the higher the stage
Stage 4 has completely penetrated
What histologic characteristic of the esophagus lends it to metastasis?
Lack of a serosa to contain the cancer
What are the four anatomic esophageal constrictions?
1) Upper Esophageal Sphincter
2) Aortic arch crosses the esophagus
3) Left Bronchus
4) Esophageal hiatus
How do the clinical constrictions of the esophagus differ from the anatomic?
Only 3x
–> Aortic arch and left bonchus are combined
What vertebral level is the esophageal hiatus located at?
T10
What is the clinical consideration that you need to keep in mind about the constrictions of the esophagus?
Be weary of constrictions on endoscopy i.e. don’t force and penetrate the wall of the esophagus
What is pill esophagitis?
Difficulty swallowing pills in the elderly leading to inflammation of the esophagus
Where is there an anatomic weakness in the esophagus prone to developing a diverticula?
Inferior border of the pharynx, specifically between the oblique thyropharyngeus and cricopharyngeus
What is the eponym for the triangle between the thyropharyngeus and cricopharyngeus?
Killian’s Triangle
What is the eponym for the diverticula that develops at Killian’s Triangle?
Zenker’s Diverticulum
What is the main symptom of a Zenker’s Diverticulum?
Halitosis
Where would you ligate the inferior thyroid artery when performing a thyroidectomy?
Above/ distal to the esophageal branch of the inferior thyroid artery
What does cirrhosis/ portal hypertension lead to in the esophagus?
Esophageal varices
What is achalasia?
- Inhibitory neurons of Meissner’s plexus have been destroyed
- Normally relaxes the Lower Esophageal Sphincter
–>Abnormally contracted LES leading to proximal esophageal dilation
Describe the lymphatic vessels of the esophagus. How does this differ from the colon?
Lymph flow moves LONGITUDINALLY i.e. the length of the esophagus in the SUBMUCOSA
**Colon lymph flow is RADIAL
What are the clinical implications of the direction of lymph flow in the esophagus?
Metastatic cells can travel cranially or caudally
Where does metastasis travel more commonly in the superior esophagus?
Cranially into the cervical lymph nodes
Where does metastasis travel more commonly in the inferior esophagus?
Caudally into the celiac trunk
What is a chylothroax? What causes a chylothorax?
Damage to the throacic duct during esophageal surgery spills lymph into the throacic cavity
What type of glands are in the pyloric area of the stomach?
Gastrin secreting G-cells
What is the function of Gastrin?
Increases the secretion of HCl from parietal cells
What is the surgical procedure that can be done for refractory PUD?
Surgical excision of the pylorus to decrease the number of gastrin secreting G-cells
Where are most ulcers found in the stomach?
Lesser curvature proximal to the angular notch
What is the angular notch?
Interface between the body of the stomach and the pylorus
What is Zollinger-Ellison Syndrome?
Tumor of gastrin producing cells, a Gastrinoma
What is the most common location for a Gastrinoma?
Gastrinoma Triangle, which is defined as:
1) Junction of cystic and common hepatic duct
2) Junction of neck and body of pancreas
3) Junction between 2nd and 3rd part of the duodenum
What are the contents of the Gastrinoma Triangle?
Pancreas
Duodenum
What gross change of the stomach is seen in Zollinger-Ellison Syndrome?
Prominent rugae due to increased parietal cell mass
Review the arterial supply of the stomach.
N/A
What are the six major arteries the supply the stomach?
1) Right gastric
2) Left gastric
3) R. gastro-omental
4) L. gastro-omental
5) Gastroduodenal
6) Splenic
What arterial variation do you need to be weary of in a gastrectomy?
Left hepatic artery can branch from the left gastric artery–impairing blood supply to the left lobe of the liver.
