Ana L2C | Anatomy of the GI

• The esophagus is a tubular organ that connects the mouth to the stomach. It is divided into three parts: upper, middle, and lower.
• Difficulties in passing an endoscope can occur at the junction of the esophagus and stomach.
• Burning and strictures develop in the lower third of the esophagus after swallowing caustic liquids.
• Esophageal carcinoma can develop at the sites of esophageal strictures.
• The upper third of the esophagus is supplied by the inferior thyroid artery, the middle third by the thoracic aorta, and the lower third by the left gastric artery.
• The upper third of the esophagus drains into the inferior thyroid veins, the middle third into the azygos veins, and the lower third into the left gastric vein, which is a tributary of the portal vein.
• The gastro-esophageal sphincter, a physiological sphincter, is located at the junction of the esophagus and stomach to prevent regurgitation.
• The stomach is the most dilated part of the gastrointestinal tract and has a J-like shape, positioned between the abdominal esophagus and the small intestine.
• The stomach is divided into four regions: cardia, fundus, body, and pyloric part.
• The stomach has distinctive features, including greater and lesser curvatures, cardial notch, and angular incisure.
• The left gastric artery is the main arterial supply to the stomach from the celiac trunk.
• The small intestine is a part of the gastrointestinal tract that extends from the stomach to the large intestine and is responsible for the final stages of food digestion and nutrient absorption.
• The small intestine is divided into three parts: duodenum, jejunum, and ileum.
• The duodenum is the shortest part of the intestine, located between the level of L1 and L3, and is mostly retroperitoneal.
• The pancreatic duct and common bile duct enter the descending duodenum through the major duodenal papilla.
• The jejunum is the proximal two-fifths of the small intestine and is characterized by a thicker wall, wider lumen, and numerous prominent folds.
• The ileum is the distal three fifths of the small intestine, mostly in the right lower quadrant, and has thinner walls, fewer and less prominent mucosal folds, more mesenteric fat, and more arterial arcades.
• The lymphatic system of the small intestine regulates tissue fluid homeostasis, participates in immune surveillance, and transports dietary fat and fat-soluble vitamins from the gut lumen.
• The jejunum and ileum are innervated by parasympathetic and sympathetic fibers via the superior mesenteric plexus, and the visceral sensation of pain arising from them is poorly localized and referred to the periumbilical region.

Test your knowledge of the anatomy of the esophagus, including its length, parts, and relationships with surrounding structures such as the vertebral column, thyroid gland, trachea, and aortic arch.