Stomach, Midgut and Associated Arteries - Anatomy Flashcards
Where do we receive the oesophagus?
The cardiac region of stomach
What is the superior extension of the cardiac region? What is it normally filled with?
Fundus
Usually filled with gas
What is the main part of the stomach?
Body
What leads into the pylorus?
Pyloric antrum leads into the pylorus (muscular thickening)
What is the pyloric sphincter?
Dictates gastric emptying into duodenum
What is pyloric sphincter controlled by?
Sympathetic nervous system and vagal fibres
What is effect of vagal fibre son pyloric sphincter?
They relax sphincter and allow food stuff in stomach to pass into duodenum
What attaches the lesser curvature to the liver?
Lesser omentum
What is attached to the greater curvature of the stomach?
Greater omentum
Describe the internal surface of the stomach
Highly folded –> rugae
What is function of rugae?
o Folds act to increase SA of stomach so it can expand as food stuff enters
o Within rugae (folds), there is the gastric pits and cells that secrete acids and relevant enzymes
What are the left and right lobes of the liver separated by?
Falciform ligament (peritoneal ligament)
What is the anterior border of the lesser sac?
Peritoneum overlying posterior surface of stomach, also have lesser omentum on anterior aspect
What is the inferior border of the lesser sac?
Peritoneum covering pancreas and the transverse mesocolon, as well as the greater omentum (that would be projecting from greater curvature and closing off lesser sac)
What arteries supply the greater curvature of the stomach?
Gastro-epiploic arteries (left and right anastomose)
Where do the branches that supply the stomach come from?
Foregut structure –> coeliac trunk
Where does the TC go to/from?
Hepatic flexure to splenic flexure
What is the greater sac divided into? By what?
Supra and infracolic compartments by the transverse mesocolon
Where does the coeliac trunk arise?
T12
What are the 3 main branches of the coeliac trunk?
- Common hepatic artery
- Left gastric artery
- Splenic artery
What does the common hepatic artery branch into?
- Hepatic artery proper
2. Gastroduodenal artery (going to duodenum)
What arteries supply the lesser curvature?
Gastric arteries (right and left anastomose at lesser curvature)
What is the right gastric artery a branch of?
Hepatic proper
What are the branches of the gastroduodenal artery?
- Right gastroepiploic
2. Superior pancreaticoduodenal
Where does the left gastroepiploic come from?
Splenic artery
Where does the splenic artery pass?
Posterior to stomach on superior aspect of pancreas (going towards spleen)
What is the midgut supplied by?
SMA arising at L1
What are the branches of the SMA?
- Inferior pancreaticoduodenal artery
- Jejunal and ileal arteries
- Middle and right colic arteries
- Ileocolic artery
What direction do the jejunal and ileal arteries go?
Left
What does the right colic artery supply?
Ascending colon and hepatic flexure of colon
What does the ileocolic artery supply?
Distal part of ileum and caecum
What do the jejunal and ileal arteries supply?
Jejunal and ileal loops
Where does the appendicular artery come from?
Terminal branch of ileocolic artery (sometimes from the posterior cecal artery or an ileal artery)
What does the appendicular artery supply?
Appendix
What does the middle colic artery supply?
Supplies the proximal 2/3 of the transverse colon
What is the middle colic artery a branch of?
SMA
What is the marginal artery?
Acts as anastomotic loop along the inner border of the colon formed by the anastomoses of the terminal branches of the SMA and IMA
What passes from the marginal artery to the colon?
Vasa recta
What are appendices epiploicae / epiploic appendices? Where are they found?
Distinguishing feature of colon (easily seen in sigmoid)
Small pouches of peritoneum filled with fat situated along colon
What are taeniae coli?
3 separate longitudinal bands of smooth muscle on the outside of the ascending, transverse, descending and sigmoid colons
Run from appendix down to rectum
This longitudinal muscle doesn’t go all the way around the colon but instead 3 bands of muscle either side. Why is this? What effect does it have?
Too short for length of colon
Forms a concertina effect –> end up with outpouchings of colon known as haustra (bubble part of colon)
What is the duo-jejunal flexure?
Junction between jejunum and duodenum
Is there a clear mark between jejunum and ileum?
No
Describe size of jejunum compared to ileum?
Jejunum is a little bigger and wider than ileum
What are plicae circulares?
Mucosal folds of the small intestine
Where are plicae circulares found?
Lower part of duodenum and jejunum but considerably decrease in ileum
Why do plicae circulares decrease in ileum?
Hopefully majority of foodstuffs has been reabsorbed here
Compare fat in mesentery of ileum to jejunum?
More fat in mesentery of ileum compared to jejunum
What supplies the jejunal and ileal loops?
Branches from SMA
Compare blood supply of jejunum and ileum
By the time they reach jejunum and ileum, they form arterial arcades and vasa recta:
Jejunum –> Large arterial arcades, fewer. Longer vasa recta.
Ileum –> More small arterial arcades. Shorter vasa recta
What is the hepatic flexure (right colic flexure)?
The sharp bend between the ascending colon and the transverse colon. The hepatic flexure lies in the right upper quadrant of the human abdomen.
What is the splenic flexure?
The sharp bend between your transverse colon and descending colon in your upper abdomen. It’s situated next to your spleen
