G.I organs Flashcards
Describe the abdominal oesophagus
Emerges through the right crus of the diaphragm at T10
Goes through the muscular part of the diaphragm which is important because it contributes to the formation of the Lower Oesophageal Sphincter which prevents gastro-oesophageal reflux
Passes from the oesophageal hiatus into the cardial orifice just left to the midline
What are the relations of the abdominal oesophagus
Anterior vagal trunk- left vagus nerve- rotation of gut during development moves these fibres anteriorly
Posterior vagal trunk- single trunk- right vagus nerve
Describe the arterial supply of the abdominal oesophagus
esophageal branches of the left gastric artery (celiac trunk)
esophageal branches from the left inferior phrenic artery (from the abdominal aorta)
Describe the stomach
Most dilated part of G.I tract
J-shaped
Lies between abdominal oesophagus and S.I
Found in epigastric, umbilical and left hypochondriac regions
Describe the different regions of the stomach
Fundus: superior to plane created by the cardial notch
Cardia: surrounds the opening
Body: bulk of the stomach, between the fundus and angular incisure
Pyloric antrum: between the pyloric canal and angular incisure
Pyloric canal: leads to the pyloric constriction where the pyloric sphincter controls flow to the duodenum
Describe the other features of the stomach
Greater curvature: most lateral curvature; point of attachment of gastrosplenic ligament and greater omentum
Lesser curvature: most medial curvature; point of attachment of lesser omentum
Cardial notch: superior angle created where the oesophagus enters
Angular incisure: bend on the lesser curvature
Describe the arterial supply to the stomach
Left gastric artery (celiac trunk)
Right gastric (hepatic artery proper)
Right gastro-omental artery (gastroduodenal artery)
Left gastro-omental (splenic artery)
Posterior gastric (splenic artery- variant)
What is important to remember about the stomach
Clinical note – on chest x-rays be aware that you can often see a gas bubble in the fundus of the stomach lying directly beneath diaphragm. Do not confuse this air bubble with air in the peritoneum, say from an intestinal perforation.
Describe the duodenum
Position: C-shaped structure adjacent to head of pancreas
Functional anatomy: lumen widest of small intestine, and all retroperitoneal apart from the first region
Above level of umbilicus
First part is attached to the liver via the hepatoduodenal ligament (part of lesser omentum)
Describe the superior part of the duodenum
aka ampulla; extends from pyloric orifice to neck of gallbladder, passing anterior to the bile duct, portal vein and IVC (only intraperitoneal part)
Just right to the body of L1
Describe the descending part of the duodenum
extends from neck of gallbladder to the lower border of vertebra LIII; crossed anteriorly by the transverse colon, and right kidney is posterior; contains the duodenal papillae
Major duodenal papilla: entrance of bile/pancreatic ducts
Minor duodenal papilla: entrance of accessory pancreatic duct (and junction of foregut/midgut)
Describe the inferior part of the duodenum
longest section, crossing IVC, aorta and vertebral column
It is crossed anteriorly by the superior mesenteric artery and vein
Describe the ascending part of the duodenum
passes upwards on the aorta to vertebra LII, terminating at the duodenojejunal flexure
What is the duodenal flexure surrounded by
surrounded by fold of peritoneum (suspensory ligament of the duodenum)
Describe the arterial supply to the duodenum
Branches from gastroduodenal artery
Branches from superior mesenteric artery
Describe clinical implications of the duodenum
The relations of the duodenum are important clinically. Anurysms can compress the duodenum or ulcers can erode into the walls of vessels.
Most duodenal ulcers occur in the superior part (duodenal cap)
Describe the position of the jejenum
proximal 2/5ths of the small intestine (mostly LUQ)
Describe the position of the ileum
distal 3/5ths of the small intestine (mostly RLQ)
Compart the jejunum to the ileum
Walls: jejunum has thicker walls with more frequent and prominent circular folds (plicae circulares)
Lumen: jejunum is larger in diameter
Arterial arcades: more prominent in the ileum
Vasa recta: longer in the jejunal supply
Mesenteric fat: larger in the ileum
Describe the large intestine
extends from distal end of the ileum to the anus, absorbing fluids and salts to form faeces in gut