16-01-23 - Oesophagus, Stomach & Duodenum Flashcards
Learning outcomes
- Describe the anatomy (position, function, relations, neurovascular supply) of the oesophagus
- Describe the anatomy (position, function, relations, neurovascular supply) of the stomach
- Describe the anatomy (position, function, relations, neurovascular supply) of the duodenum
- Discuss the clinical implications of the anatomy of the lower end of the oesophagus, the stomach and the duodenum
- Identify anatomical structures on medical images
What are the embryonic gut divisions?
What does each section contain?
How is blood supply, lymphatics, and innervation linked between these divisions?
- The abdominal organs are divided into 3 parts based on embryological origin:
1) Foregut
* Oesophagus to mid-duodenum
* Liver + gall bladder
* ½ of pancreas
2) Midgut
* Mid-duodenum to proximal 2/3rds of Transverse colon
* ½ of pancreas
3) Hindgut
* Distal 1/3rd of Transverse colon to Proximal ½ of Anal canal
* Arteries and veins of each area have similar names
* Lymphatics from each share a similar path
* Nerves from each area follow a common path
What is the arterial supply of the stomach?
What are the 3 divisions of the coeliac trunk?
- The arterial supply of the stomach is the coeliac trunk
- 3 divisions of the coeliac trunk:
1) Common hepatic artery
2) Left gastric artery
3) Splenic artery
What is the role of the oesophagus?
Where does the oesophagus start?
Where does it descend between?
Where does it enter the thorax?
Where does it enter the abdominal cavity?
- The role of the oesophagus is the transport of food and fluid to stomach by peristaltic waves
- The oesophagus starts in the midline as the continuation of the pharynx at C6, inferior border of cricoid cartilage
- It descends between the trachea and the vertebral column
- The oesophagus enters the thorax behind trachea, with the arch of the aorta to its left in the superior mediastinum
- It then enters the abdominal cavity at T10, slightly left of the midline
What are the 4 non-pathological constrictions of the oesophagus?
What level is each constriction at?
What is the significance of the
Cricopharyngeal sphincter?
What are 3 reasons why constrictions can cause problems?
- 4 non-pathological constrictions of the oesophagus:
1) Upper oesophageal [cricopharyngeal] sphincter – Level of T6
2) Arch of aorta – Level of T4
3) Left main bronchus
4) Diaphragm – Level of T10
- The Cricopharyngeal sphincter between the pharynx and the oesophagus prevents air entering the stomach via oesophagus
- 3 reasons why constrictions can cause problems. Constrictions are more likely to:
1) Are more likely to cause blockage
2) Hinder passage of instruments
3) Slow down the passage of caustic substances → more damage
Superior, middle, and inferior 1/3rd of the oesophagus:
* Muscle type
* Swallowing
* Arterial supply
* Venous drainage
* Innervation
* Lymphatic drainage
How large is the abdominal oesophagus?
Where does the abdominal oesophagus extend between?
Where does it enter into the abdominal cavity?
What is the abdominal oesophagus tethered by?
- The abdominal oesophagus is the shortest part
- It extends from the oesophageal hiatus to the cardiac orifice of the stomach
- It passes through the right crus of the diaphragm at T10 to enter the abdominal cavity
- The abdominal oesophagus is tethered to the margins of the oesophageal hiatus by the phreno-oesophageal ligament
What is the arterial supply of the abdominal oesophagus?
What 2 places does the venous drainage of the abdominal oesophagus go to?
What is the nerve supply to the abdominal oesophagus?
Where can pain from the lower oesophagus be referred to?
What is the lymph drainage of the oesophagus?
- Arterial supply of the abdominal oesophagus is from the branches of left gastric artery, a branch of coeliac trunk
- Veins of the abdominal oesophagus drain to the portal vein (left gastric, short gastric veins) and azygos system (oesophageal veins).
- Nerve supply is by the oesophageal plexus
- Parasympathetics from Vagus
- Sympathetics from greater splanchnic nerve
- Pain from the lower oesophagus is referred to the retrosternal area
- The lymph drainage of the oesophagus are the left gastric lymph nodes, which then drain into the celiac lymph nodes
What can be triggered due to cirrhotic liver disease?
- Cirrhotic liver disease can lead to the liver tissue being inflexible and tough, which compresses the hepatic portal vein, leading to portal hypertension
- Instead of blood from going the hepatic portal vein to the IVC to the heart, it travels to the thoracic cavity and is drained by other veins (e.g azygos)
- These veins can’t handle much blood and will swell, leading to blood backing into oesophageal veins and forming oesophageal varices (expanded blood vessels in the oesophagus)
Where is there a high-pressure zone (HPZ) around the oesophagus?
What are 2 major anti-reflux mechanisms of the oesophagus?
What are 2 minor anti-reflux mechanisms of the oesophagus?
What is the oesophageal sphincter made up of?
What is achalasia?
What can cause achalasia?
- There is a high-pressure zone (HPZ) around the lower 2-4 cm of oesophagus
- 2 major anti-reflux mechanisms of the oesophagus:
1) Circular smooth muscle fibers in the lower oesophagus
2) The right crus of the diaphragm
- 2 minor anti-reflux mechanisms of the oesophagus:
1) Clasp fibres
2) Oblique entry of the oesophagus into the stomach
- Anatomical and physiological features are collectively referred to as the lower oesophageal sphincter
- Achalasia is a rare disorder of the food pipe (oesophagus), which can make it difficult to swallow food and drink
- Achalasia can be caused by ganglion cells in the myenteric plexus of the distal oesophagus and gastro-oesophageal junction being reduced or absent
What structures extend up the abdominal oesophagus?
How is the gastro-oesophageal function identified?
What is Barrett’s oesophagus?
What is a Mallory-Weiss tear?
How is it often caused?
- Gastric fundal mucosal folds extend a variable distance up the abdominal oesophagus.
- The gastro-oesophageal junction is usually identified by a circumferential ‘zigzag’ line (‘Z line’) between the pale pink oesophageal squamous epithelium above and the red columnar epithelium below
- Barrett’s Oesophagus is the pathological replacement of oesophageal squamous epithelium by gastric columnar epithelium
- A Mallory-Weiss tear is a tear of the tissue of your lower oesophagus.
- It is most often caused by violent coughing or vomiting
What is the stomach?
Where is it located?
What is the Labbe triangle?
What 3 structures make up Labbe triangle?
- The stomach is a muscular sac
- The stomach is located in epigastric, left hypogastric (hypochondrial) and, partially, umbilical regions
- Labbe triangle is the location where the stomach is normally in contact with the abdominal wall
- 3 structures make up Labbe triangle:
1) Left costal arch
2) Lower border of the liver
3) Horizontal line connecting the tips of right and left 9th costal cartilages
What are 7 functions of the stomach?
- 7 functions of the stomach:
1) Temporary storage of ingested food
2) Mechanical breakdown of solid food
3) Chemical digestion of proteins
4) Mixes the food with gastric secretions to form chyme
5) Regulation of the rate of passage of the chyme to the duodenum
1) Secretion of:
* Mucus
* Acid to aid digestion and absorption of iron
* Intrinsic factor for vitamin B12 absorption
* Gut hormones
2) Microbial defence
What is the gastric mucosa of the stomach lined with?
What is the purpose of this?
What are 3 different cell types in the stomach?
What do they each produce?
- The gastric mucosa of the stomach is lined by a simple columnar epithelium (surface lining cells) which secrete a thick coating of alkaline mucous
- This protects the gastric mucosa from the effects of acid and enzymes (autodigestion)
- 3 different cell types in the stomach:
1) Parietal (oxyntic) cells
* Make hydrochloric acid, and intrinsic factor
* Intrinsic factor is needed for absorption of vitamin B12 in the terminal ileum
2) Chief (Peptic, zymogenic) cells
* Produce precursors of pepsin (as well as lipase)
* Pepsin down proteins into smaller peptides
3) DNES (formerly APUD) cells
* Produce hormones such as gastrin (by G cells in the pyloric antrum) and somatostatin (by delta cells in pyloric antrum)
What 5 structures is the stomach related to anteriorly?
What 8 structures is the stomach related to posteriorly?
- 5 structures the stomach is related to anteriorly:
1) Anterior abdominal wall
2) Left costal margin
3) Diaphragm
4) Left pleura & lung (via diaphragm)
5) Left lobe of the liver - 8 structures the stomach is related to posteriorly:
1) Lesser sac
2) Spleen
3) Upper pole of left kidney
4) Left suprarenal gland
5) Pancreas
6) Splenic artery
7) Transverse colon
8) Transverse mesocolon
What are the 4 parts of the stomach?
What are the 4 surfaces of the stomach?
- 4 parts of the stomach:
1) Cardia
* Surrounds the opening of the oesophagus into the stomach
2) Fundus
* Part above the level of the cardiac orifice (usually filled with air)
3) Body
4) Pyloric part
* Contains Pyloric (Gastric) antrum and Pyloric canal
- 4 surfaces of the stomach:
1) Greater curvature
2) Lesser curvature
3) Anterior surface
What does the muscular wall of the stomach contain?
How is the pyloric sphincter formed?
What is its purpose?
- The muscular wall of the stomach contains longitudinal, circular & oblique fibres
- The circular fibres in the pyloric region forms the pyloric sphincter
- The pyloric sphincter controls the outflow of gastric contents into the duodenum
What is a barium meal?
How does the procedure work?
- A barium meal is an examination of your stomach and your oesophagus
- You will be asked to drink a liquid that is visible on x-ray to see what happens when you swallow.
- The procedure will take place in the radiology department and will take approximately 20 minutes.
Where do arteries that supply the stomach originate from?
Where does the coeliac trunk originate from?
What are the 5 arteries that supply the stomach?
What are they each branches of?
Where can they each be found?
What part of the stomach do they each supply?
- All arteries that supply the stomach are either primary (direct) or secondary branches of the coeliac trunk that form an anastomotic ring around the stomach
- Coeliac trunk originates at the lower border of T12 (upper border of L1 vertebra)
- 5 arteries that supply the stomach:
1) Left gastric artery
* Direct branch of the coeliac trunk
* Runs along the lesser curvature of the stomach
* Supplies the abdominal oesophagus, proximal lesser curvature & adjacent body of the stomach
2) Right gastric artery
* Branch of the common hepatic artery
* Runs along the lesser curvature
* Supplies the distal lesser curvature & adjacent body of the stomach
3) Left gastroepiploic (gastro-omental) artery
* Branch of the splenic artery
* Runs in the gastro-splenic (gastrolienal) ligament
* Supplies the left side the greater curvature & adjacent body of the stomach
4) Right gastroepiploic artery
* Branch of the gastroduodenal artery, which is a branch of the common hepatic artery
* Supplies the right side of the greater curvature & adjacent body of the stomach
5) Short gastric arteries
* Branches of the splenic artery
* Runs in the gastro-splenic (gastrolienal) ligament
* Supplies the fundus of the stomach
Label these stomach arteries
What does the venous drainage of the stomach run alongside?
Where do they each drain into?
- The venous drainage of the stomach runs parallel to the arteries
- Left and right gastric veins drain into the hepatic portal vein
- Short gastric and left gastroepiploic (gastro-omental) veins drain into the splenic vein, which drains into the hepatic portal vein
- The right gastroepiploic vein drains into the superior mesenteric vein, which drains into the hepatic portal vein
Where does lymph from the stomach pass to?
Where does lymph from the 4 different zones of the stomach drain to?
- Initially lymph from the stomach passes to nodes that lie along the arteries
- Eventually lymph will be drained by the coeliac nodes
- Where lymph from the 4 different zones of the stomach drains to:
1) Zone I (inferior gastric) → subpyloric and omental nodes
2) Zone II (splenic) → pancreaticosplenic nodes
3) Zone III (superior gastric) → superior gastric nodes
4) Zone IV (hepatic) → suprapyloric nodes
What is the sympathetic supply to the stomach?
What type of innervation does this supply?
What is the parasympathetic supply to the stomach?
What 3 effects does parasympathetic supply have on the stomach?
Where is pain from the stomach referred to?
- The sympathetic supply to the stomach is from the greater splanchnic nerve (T5-9) from the coeliac plexus
- This provides pain and vasomotor innervation
- Parasympathetic supply comes from the vagal trunks
- 3 effects parasympathetic supply has on the stomach:
1) Increase secretion
2) increase motility, relax sphincters
3) Afferents for emesis
- Pain from stomach is referred to the epigastric region and lower chest
What is the bed of the stomach?
What 8 structures make up the bed of the stomach?
- Structures against which the posteroinferior surface of the stomach lie is called the bed of stomach
- 8 structures make up the bed of the stomach:
1) Left crus of the diaphragm
2) Spleen
3) Left suprarenal gland
4) Upper pole of the left kidney
5) Body & tail of pancreas
6) Transverse mesocolon
7) Left colic (splenic) flexure
8) Splenic artery
What is a hiatus herniation?
What groups is it more common in?
What are the 2 types of hiatus herniation?
What symptoms can hiatus hernias have?
What can para-oesophageal hernias cause?
- Hiatus herniation is herniation of the stomach through the diaphragm into the mediastinum (Not to be confused with diaphragmatic hernia).
- It is more common in the elderly and the obese.
- 2 types of hiatus herniation:
1) Sliding hernia (>90%)
2) Para-oesophageal (rolling) hernia - A hiatus hernia may be asymptomatic or be associated with symptoms of gastro-oesophageal reflux (heartburn).
- Para-oesophageal hernias can cause obstruction and/or ischaemia of the herniated stomach
How long is the small intestine?
Where does the small intestine extend between?
What occurs in the small intestine?
What are the 3 parts of the small intestine?
- The small intestine is the longest part of the alimentary canal (relating to nourishment or sustenance)
- The small intestine extends from the pylorus to the ileocaecal valve
- In the small intestine, nearly all food/nutrient absorption takes place
- 3 parts of the small intestine:
1) Duodenum
2) Jejunum
3) Ileum
What are the 4 parts of the duodenum?
What levels are these parts?
Where are these parts located?
What is the transpyloric plane?
What does the duodenum receive from the pancreas and the liver?
What are the functions of the duodenum?
What is The duodenojejunal flexure (ligament of Treitz) ?
- 4 parts of the duodenum:
1) Superior (Ampulla or duodenal cap) – on the transpyloric plane – L1
2) Descending - right of the midline from L2 to L3
3) Horizontal – at L3
4) Ascending – L2
- Part 1 intraperitoneal, parts 2-4 retroperitoneal
- The transpyloric plane, also known as Addison’s plane, is an imaginary axial plane located midway between the jugular notch and superior border of pubic symphysis, at approximately the level of L1 vertebral body
- The duodenum receives digestive enzymes from the pancreas via the main pancreatic duct and bile from the liver and gallbladder via the common bile duct
- The functions of the duodenum are digestion (especially of fats) and absorption
- The duodenojejunal flexure (ligament of Treitz) is a sharp angle in the small intestine between the duodenum and the jejunum
What is the minor and major duodenal papilla?
- The Minor duodenal papilla is the opening of the accessory pancreatic duct
- The Major duodenal papilla is the Common opening of the common bile and main pancreatic ducts
- It also serves as the boundary between the foregut and the midgut
Up to which point is the duodenum derived from the foregut?
What artery supplies this part of the duodenum?
What 3 branches of this artery supplies this part of the duodenum?
What is the rest if the duodenum derived from?
What artery supplies this part of the duodenum?
What branch of this artery supplies this part of the duodenum?
Where is there collateral circulation present in this area?
What is the gastroduodenal artery at risk with?
- Part of the duodenum up to the major duodenal papilla (ampulla of Vater) is derived from foregut
- This part of the duodenum is supplied by branches of the common hepatic artery (continues as hepatic artery proper):
1) Gastroduodenal artery
2) Supraduodenal artery
3) Superior pancreaticoduodenal artery (anterior and posterior)
- The rest of the duodenum is derived from the midgut
- This part of the duodenum is supplied by branches of superior mesenteric artery: inferior pancreaticoduodenal artery (anterior and posterior)
- There is collateral circulation between coeliac trunk and superior mesenteric artery
- The gastroduodenal artery is at risk with posterior ulcers of the 1st part of the duodenum
Where do lymph vessels from the anterior and posterior duodenum drain to?
Where do veins in the duodenum drain to?
- Lymph vessels in the anterior duodenum drain to the pyloric or pancreaticoduodenal lymph nodes
- Lymph vessels in the posterior duodenum drain to the mesenteric lymph nodes
- Veins in the duodenum drain to hepatic portal vein, either directly or indirectly through the superior mesenteric and splenic veins
What is the sympathetic supply to the duodenum?
What is the parasympathetic supply to the duodenum?
- Sympathetic fibres go to the duodenum from the greater splanchnic nerves (T5-9) + lesser splanchnic nerve (T10 and T11)
- Parasympathetic fibers go to the duodenum from the vagus via the coeliac & superior mesenteric plexuses
What are bariatric surgeries?
What are 3 examples of bariatric surgeries?
What is the Whipple’s procedure for?
- Bariatric surgery includes a variety of procedures performed on people who are obese
- 3 examples of bariatric surgeries:
1) Gastric bypass
2) Gastric sleeve or vertical gastrectomy
* A sleeve gastrectomy is where a large part of the stomach is removed so it’s much smaller than it was before
3) Adjustable gastric banding
- A Whipple’s procedure is performed on the head of the pancreas and is used for pancreatic cancer
Duodenum anatomical relations
