Anatomy - The Stomach Flashcards
Name the 4 main regions of the stomach.
- Cardia. 2. Fundus. 3. Body. 4. Pylorus.
What vertebral levels does the stomach lie between?
T7 to L3.
What are the folds of the internal stomach surface called?
Rugae.
Name the 2 sphincters of the stomach.
- Inferior oesophageal sphincter. 2. Pyloric sphincter.
Which sphincter of the stomach is physiological (containing no sphincteric muscle)?
The inferior oesophageal sphincter.
What forces act on the inferior oesophageal sphincter?
- The diaphragm exerts pressure on the hiatus.
- The lumen is collapsed in the normal state
- The oesophagus enters the stomach at a right angle; when the stomach is full this is closed off.
What is the function of the pyloric sphincter?
Controls the exit of chyme from the stomach.
What vertebral level is the coeliac trunk found?
T12.
Where does the foregut begin and end?
The mouth to the 2nd part of the duodenum (major duodenal papilla).
What is the blood supply to the greater curvature of the stomach?
The short gastrics, and the right and left gastro-epiploic arteries.
What is the blood supply to the lesser curvature of the stomach?
The left and right gastric arteries.
What is the right gastric artery a branch of?
The proper hepatic artery which arises from the common hepatic artery from the coeliac trunk.
What is the right gastro-epiploic artery a branch of?
It is the terminal branch of the gastroduodenal artery, this arises from the common hepatic artery which arises from the coeliac trunk.
What is the left gastro-epiploic artery a branch of?
The splenic artery which arises from the coeliac trunk.
What vein does venous blood from the GI tract, liver and spleen drain into?
The hepatic portal vein (goes to the liver).
What supplies sympathetic innervation to the stomach (foregut)?
The greater splanchnic nerve (T5-T9).
What supplies parasympathetic innervation to the stomach (foregut)?
The Vagus nerve Cn 10.
Is contraction of the stomach sphincters a sympathetic or parasympathetic action?
Sympathetic. (Parasympathetic = rest and digest).
At what vertebral level does the oesophagus pass through the stomach?
T10.
What structures pass through the diaphragm along side the oesophagus?
Vagus nerves and the oesophageal arteries and veins.
What does the left gastric artery supply?
The superior part of the lesser curvature of the stomach.
What structures lie anterior to the stomach?
The anterior abdominal wall and the left lobe of the liver.
What nerve lies anterior to the abdominal oesophagus and which posterior?
Left vagus - anterior. Right vagus - posterior. (LARP)
What are the 3 major branches of the Coeliac trunk?
The left gastric, the splenic and the common hepatic.
What does the left gastric artery supply?
The lesser curvature of the stomach and lower oesophagus.
What branches does the splenic artery give off?
- The short gastric arteries. - The pancreatic arteries. - The left gastroepiploic artery. - 5 branches just before it reaches the Spleen.
What do the short gastric arteries supply?
The greater curvature of the stomach.
What does the left gastroepiploic artery supply? What does anastomose with?
It supplies the greater curvature of the stomach. It anastomoses with the right gastroepiploic artery.
Name the 2 branches of the common hepatic artery.
- Proper hepatic artery. 2. Gastroduodenal artery.
Name the 2 branches of the Gastroduodenal artery.
- Right gastroepiploic artery (supplies greater curvature of the stomach). 2. Superior pancreaticoduodenal artery (supplies head of pancreas).
In which two abdominal regions would you find the stomach?
epigastric and umbilical
Describe the four main anatomical divisions of the stomach?
- cardia - surrounds a superior opening of the stomach (T11)
- fundus - the rounded, often gas-filled portion superior to and left of the cardia
- body - the largest central portion inferior to the fundus
- pyloras - the area connects the stomach to the duodenum
- atrium, canal and sphincter
- Sphincter marks the transpyloric plane at the level of L1
Describe the greater curvature?
- Long, convex lateral border of the stomach
- Arises from the cardiac notch, arches backwards and passes Inferiorly to the left
- curves to the right and continues medially to reach the pyloric atrium
- supplied by short gastric arteries and the right and left gastroepiploic arteries
Describe the lesser curvature?
- Forms the shorter, concave, medial surface of the stomach
- most inferior part, the angular notch, Indicates the junction of the body and the pyloric region
- gives attachment to the hepatogastric Ligament
- supplied by the left gastric artery and the right gastric branch of the hepatic artery
Describe the inferior oesophageal sphincter?
- the oesophagus passes through the diaphragm through the oesophageal hiatus at the level of T10
- inferior oesophageal sphincter is at T11
- allows food to pass through the cardiac orifice into the stomach
- not under voluntary control
Describe the pyloric sphincter?
- between the pylorus and the first part of the duodenum
- controls the exit of chyme from the stomach
- Is an anatomical sphincter, so contain smooth muscle that constrict to limit the discharge of stomach contents passing through
- stomach emptying occurs intermittently when intra-gastric pressure overcomes the resistance of the pylorus
- The pylorus is normally contracted but gastric peristalsis pushes chyme into the duodenum
Describe the greater omentum?
- Double layer of peritoneum
- Hangs down from the greater curvature of the stomach
- folds back on itself to attach to the transverse colon
- contains many lymph nodes as it plays a role in immunity and reducing the spread of intra-peritoneal infections
Describe the lesser omentum?
- continuous with the peritoneal layers of the stomach and duodenum
- arises from the lesser curvature and attaches to the liver
- main function is to attach the stomach and duodenum to the liver
Describe the neurovascular supply of the stomach’s Lesser curvature?
- arterial supply from the coeliac trunk (and branches)
- left gastric artery
- right gastric artery (branch from the common hepatic artery)
Describe the vascular supply of the stomach’s greater curvature?
- left gastroepiploic artery (Branch of the splenic artery)
- right gastroepiploic artery (Branch of the gastroduodenal artery)
- short gastric artery ( branch of the splenic artery)
What is the venous drainage from the stomach?
- veins of the stomach run parallel to the arteries
- left and right gastric veins drain into the hepatic portal vein
- short gastric vein drains into the superior mesenteric vein
How’s the stomach innervated?
- from the autonomic nervous system
- Parasympathetic nerve supply - anterior and posterior vagal trunks (CN X)
- sympathetic nervous supply - T5-9, passes to the coeliac plexus via the greater splanchnic nerve
How is lymph collected in the stomach?
- the gastric lymphatic vessels travel with the arteries along the greater and lesser curvature of the stomach
- drains into the gastric and gastro-omental lymph nodes
- drain into the coeliac lymph nodes located on the posterior abdominal wall
What are Rugae?
- Folds of the mucosa allowing for greater surface area for stretching of the stomach to accommodate food
What is the gastric bed? where is it found and what does it contain?
- behind the lesser sac is the pancreas, splenic artery, and part of the duodenum
What is the clinical relevance of a peptic ulcer?
- damage to the mucosa due to the high acidity of the stomach
- the ulcer may erode through the gastric wall into adjacent structures
- including blood vessels and the structures of the gastric bed
- May spread by the lymphatics to the coeliac axis or veins to the liver
Describe the coeliac trunk?
- artery in the foregut, branches in front of the aorta just below the diaphragm
- supplies from the lower third of the oesophagus the second part of the duodenum
- also supplies the liver and parts of the pancreas
Where do veins in the lower third of the oesophagus usually drain into? What is its clinical relevance?
- hepatic portal vein and veins in the chest that drain into the superior vena cava
- in cirrhosis, the portal venous channels become progressively smaller so blood flow is redirected to flow up the veins of the oesophagus and into the superior vena cava
- called porto-systemic shunt via a porto-systemic anastomosis
- causes varicose veins of the oesophagus that bleed easily
Where do peptic ulcers commonly form?
- posterior wall of the first part of the duodenum
- can a row the duodenal wall into the gastroduodenal artery
- causing very brisk bleeding
At what level does the oesophagus pass through the diaphragm? which structures accompany it?
- T10
- vagal trunks, inferior oesophageal artery and vein
What structure attaches the stomach to the liver?
- the lesser omentum
What structures lie in front and behind the stomach?
- left lobe of the liver, anterior abdominal wall
- the lesser sac, and behind that the pancreas and diaphragm
Hypertrophy of the pyloric sphincter can cause what?
Vomiting of gastric contents.
What is the nerve supply of the stomach?
Parasympathetic nerve supply comes from the posterior and anterior vagal trunks, derived from the vagus nerve. Sympathetic from the celiac plexus.