Gastroenterology Lesson Notes

University:
Stanford University
Course:
MED 101 | Human Anatomy
Academic year:

2023
Views:

367

Pages:

1
Author:

larbi43100

GastroenterologyGastroesophageal refluxThe abdominal esophagus measures 1 to 2.5 centimeters in length and opensinto the stomach at the level of the cardia which is located approximately 40cm from the incisors. Among the formations involved in the creation ofanti-reflux barriers, the lower esophageal sphincter (made up of smoothmuscle fibers) plays a preponderant role.The esophageal lumen is lined with non-keratinized stratified squamousepithelium (like that of the oropharynx). Pale pink in color at endoscopy, itcontinues through the glandular epithelium of the stomach, more reddish, froma transition zone called the Z line.Gastroesophageal reflux is a pathological reflux of part of the gastric contents(hydrochloric acid, pepsin), or even intestinal contents (bile, pancreatic enzymes)into the esophagus. All forms combined, it affects 40% of the population on amonthly basis (7 to 10% on a daily basis).Inappropriate transient relaxations of the lower esophageal sphincter-The loweresophageal sphincter opens normally after swallowing. Its inappropriate transientrelaxations occur without swallowing and can persist for up to 2 hours. Thisphenomenon is the main mechanism explaining gastroenterology reflux (90% ofcases).Hiatal hernias-These are intermittent or permanent protrusions of part of thestomach into the thorax through the esophageal hiatus of the diaphragm.There are two types: sliding hernias and rolling hernias. Sliding hiatal hernias, whichare the most common (95% of hiatal hernias), are defined by the passage of theabdominal esophagus, the cardia and the greater gastric tuberosity into themediastinum. During a rolling hiatal (or paraesophageal) hernia, only the large gastrictuberosity is found in the thorax. Of these two types of hiatal hernias, only slidinghernias cause gastroesophageal reflux.