The Stomach - Anatomy Flashcards
What are the 4 main anatomical divisions of the stomach?
- Cardia
- Fundus
- Body
- Pylorus
Where is the cardia?
Surrounds the superior opening of the stomach at the T11 level
Where is the fundus?
The rounded, often gas filled portion superior to and left of the cardia
Where is the body?
The large central portion inferior to the fundus
Were is the pylorus?
This area connects the stomach to the duodenum
What is the pylorus divided into?
- Pyloric antrum
- Pyloric canal
- Pyloric sphincter
What do the medial and lateral borders of the stomach form?
Are curved, forming the lesser (medial surface) and greater (lateral surface) curvatures
What surface forms the lesser curvature?
Medial surface
What surface forms the greater curvature?
Lateral surface
Where does the greater curvature arise? Where does it end?
At the cardiac notch, arching backwards and passing inferiorly to the left. It curves to the right as it continues medially to reach the pyloric antrum.
What supplies the greater curvature?
The short gastric arteries and the right and left gastro-omental arteries supply branches to the greater curvature
Which curvature is longer?
Greater curvature
Describe shape of greater curvature
Long, convex
Describe shape of lesser curvature
Shorter, concave
What is the most inferior part of the lesser curvature called? What does it indicate?
The angular notch
Indicates the junction of the body and pyloric region
What does the lesser curvature give attachment to?
Hepatogastric ligament
What is the lesser curvature supplied by?
The left gastric artery and right gastric branch of the hepatic artery
What is found superior to the stomach?
Oesophagus and left dome of diaphragm
What is found anterior to the stomach?
Diaphragm, greater omentum, anterior abdominal wall, left lobe of liver, gall bladder
What is found posterior to the stomach?
Lesser sac, pancreas, left kidney, left adrenal gland, spleen, splenic artery, transverse mesocolon
How many sphincters of the stomach are there? Where are they located? What is their function?
2 - located at each orifice. They control the passage of material entering and exiting the stomach.
- Inferior oesophageal sphincter
- Pyloric Sphincter
Where does the oesophagus pass through the diaphragm? What level is the inferior oesophageal sphincter (LES)?
Through the oesophageal hiatus at T10
Descends a short distance to the inferior oesophageal sphincter at the T11 level
What does the inferior oesophageal sphincter mark?
The transition point between the oesophagus and stomach
Where is the superior oesophageal sphincter located?
In the pharynx
What is function of inferior oesophageal sphincter?
It allows food to pass through the cardiac orifice and into the stomach and is not under voluntary control.
Where is the pyloric sphincter?
Between the pylorus and the first part of the duodenum
What is function of pyloric sphincter?
It controls of the exit of chyme (food and gastric acid mixture) from the stomach
How does the pyloric sphincter differ from the inferior oesophageal sphincter?
This is an anatomical sphincter. It contains smooth muscle, which constricts to limit the discharge of stomach contents through the orifice.
When does emptying of the stomach occur?
Occurs intermittently when intragastric pressure overcomes the resistance of the pylorus
Why is the pylorus normally contracted?
So that the orifice is small and food can stay in the stomach for a suitable period.
What is the peritoneum?
Within the abdominal cavity, a double layered membrane called the peritoneum. supports most of the abdominal viscera and assists with their attachment to the abdominal wall
What are the greater and lesser omenta?
2 structures that consist of peritoneum folded over itself (two layers of peritoneum – four membrane layers). Both omenta attach to the stomach.
Where does the greater omentum hang down from?
Hangs down from the greater curvature of the stomach and folds back upon itself where it attaches to the transverse colon
How does the greater omentum play a key role in GI immunity?
It contains many lymph nodes and may adhere to inflamed areas - minimising the spread of intraperitoneal infections.
Where does the lesser omentum arise at?
This smaller peritoneal fold arises at the lesser curvature and ascend to attach to the liver
What is the main function of the lesser omentum?
Attach the stomach and duodenum to the liver.
What does the greater and lesser omenta divide the abdominal cavity into?
The greater and lesser sac
The stomach lies immediately anterior to the lesser sac
How do the greater and lesser sacs communicate?
Via the epiploic foramen, a hole in the lesser omentum.
Where does the arterial supply to the stomach come from?
The celiac trunk and its branches
Where do anastomoses form in the arterial supply of the stomach?
Anastomoses form along the lesser curvature by the right and left gastric arteries and along the greater curvature by the right and left gastro-omental arteries
- Right gastric
- Left gastric
- Right gastro-omental
- Left gastro-omental
What is the right gastric artery?
Branch of the common hepatic artery, which arises from the coeliac trunk.
What is the left gastric artery?
arises directly from the coeliac trunk
What is the right gastro-omental artery?
Terminal branch of the gastroduodenal artery, which arises from the common hepatic artery.
What is the left gastro-omental artery?
Branch of the splenic artery, which arises from the coeliac trunk.
Where do the veins of the stomach run?
Parallel to the arteries
Where do the right and left veins drain into?
The hepatic portal vein
Where does the short gastric vein, left and right gastro-omental veins ultimately drain into?
Superior mesenteric vein
Where does the stomach receive innervation from?
The autonomic nervous system
- Parasympathetic nerve
- Sympathetic nerve
Where does the parasympathetic nerve supply arise from
The anterior and posterior vagal trunks, derived from the vagus nerve.
Where does the sympathetic nerve supply arise from?
The T6-T9 spinal cord segments and passes to the coeliac plexus via the greater splanchnic nerve. It also carries some pain transmitting fibres.
Where do the gastric lymphatic vessels travel?
With the arteries along the greater and lesser curvatures of the stomach.
Where does lymph fluid drain into?
Lymph fluid drains into the gastric and gastro-omental lymph nodes found at the curvatures.
Efferent lymphatic vessels from these nodes connect to the coeliac lymph nodes, located on the posterior abdominal wall.
