Anatomy GI 5 Esopahgus and Stomach Flashcards
Where does esophagus occupy in mediastinum
posterior mediastinum in chest
exposed to low pressure
What part of diaphragm does it travers
muscular portion of diaphragm00
where is esopahgeal hiatous on diaphragm
approx T10 vertera
Esophagus intraabdominal for….how long?
~6cm
Exposed to the higher intaabdominal pressure
Where does esophagus enter stomach? How does this help with Gastroesopheal reflux?
Entes stomach at ESOPHAGOGASTRIC JUNCTION at an acute angle
angle formed, which in additoint o high resting muscce tone helps miminizme reflux of gastric content into esophageal lumen
PRevents gastroesophageal reflux
Is pressure in chest cavity positive or negative?
negative!
Is pressure in abdomen positive or negative?
positive!
tehrefore this postiive pressure pushes esophagus to be closed when esophagus in abodmin
How long is the ESOPHAGOGASTRIC JUNCTION
~7CM segment of high muscle tone (physiological sphincter)
- relaxes upon swallowing
- no visible anatomic sphicnter present
- site where squamous mucosa of esophagus joins columnar gastric mucosa known as Z line
What is the Z line
site where squamous mucosa of esophagus joins the colunar gastric mucosa (in stomach)
Esophagogastric junction!!
Is there an anatomical spchincter present/
no!
how does esophagogastric junction minimize reflux of gastric content into esopahgus
High pressure due to SM contraction (high pressure zone)
Are squmaous cells protected from acid?
No! but columnar are again
Is internal muscle circular or longitudinal?
internal is circular.
External is longitudinal
What nerve innervates esophagus
Vagus Nerves- PS inneration
Stimulates peristalsis
What is the sympathetic iinnervation? What does it do?
via celiac plexus
Mainly causes vasoconstriction of esophageal arteries and some decrease in muscular activity
