Oesophagus, stomach and duodenum Flashcards
what are the 3 gut divisions and what does each part include?
1) Foregut:
- liver
- gallbladder
- pancreas
(half way along the oesophagus to the 2nd part of the duodenum)
2) midgut: 1/2 way along the 2nd part of the duodenum to the proximal 2/3 transverse colon.
3) hindgut:
- distal 1/3 transverse colon to the proximal half of the anal canal.
describe the blood supply to the gut divisions?
each region is supplied by a branch of the abdominal aorta.
foregut= coeliac trunk
midgut= superior mesenteric
hindgut = inferior mesenteric
what are the 3 main branches of the coeliac trunk?
1- splenic
2- left gastric
3- common hepatic
what are the 4 physiological constrictins of the oesophagus?
- cricopharyngeal sphincter C6
- arch of the aorta T4
- left main bronchus
- oesophageal hiatus T10
what is the problem with the physiologcal constrictions of the oesophagus?
- they may impede instrumets
- predispose to blockage
- site of damage if caustic substances gets trapped
at what level is oesophagus continues with the pharynx?
what route does it take from here?
- continous with the pharynx at C6
- from here it is in the midline between the trachae and the vertebral column, descending towards the left
- enters the abdomne through the diapghram at T10
how is the oesophagus connected to the diapghram?
by the phrenico-oesophageal ligament
- this has independant movement during function
what is the abdominal eosophagus?
this is the 1.25 cm of oesophageal hiatus to the cardial orifice of stomach
describe the arterial suply of the abdominal oesophagus?
supplied by the oesophageal branch of the left gastric artery (from coeliac trunk)
describe the venous supply of the abdominal oesophagus?
it has 2 venous drainage supplies:
it is supplied by the oesophageal branch of the left gastric vein
this will drain into either..,
1- hepatic portal system (left gastric vein)
2- azygos system via the oesphageal veins.
what is the porto-systemic anastomoses prone to?
it is prone to oesopheal varices in cases of portal hypertension
where does the oesophageal plexus supply?
The esophageal plexus supplies autonomic innervation to the mid and lower esophagus and transmits parasympathetic fibers to the abdomen.
describe the sympathetic and parasympathetic supply of the oesophageal plexus?
parasympathetics= from vagus nerve (they become vagal trunks)
sympathetics = from the greater splanchnic nerves T5-T9
lymphatics of the oesophagus?
lymphatics = left gastric nodes to coeliac nodes
where is the lower oesophageal pain reffered too?
retrosternal area
what are the multiple components of the oesphageal sphincter?
what is their overall function?
- circular smooth muscle of the lower oesophagus
- right crus of diapghram
- ‘clasp’ fibres at junction with stomach
- oblique entry into stomach
FUNCTION:
to prevent refluc of stomach contents
all the components act colectivly to work as a sphincter
what is achalasia?
problem with the lower oesophageal sphincter
- this makes it difficult to swallow
- sphincter resists opening, linked to fewer ganglia in myenteric plexus at distal oesophagus
what is the Z line?
- this is the junction between mucosa of the stomach and oesophagus
- irregular and jagged
what is the differance in epithelium between oesophagus and stomach?
oesophagus = non-keratinised stratified squamos epithelium
stomach = simple columnar epithelium with gastric pits (gastric secretions)
what is Barret’s oesophagus?
- a premalignant metaplastic change in the lower oesophagus
- the oesophagus epithelium will change to gastric epithelium
what is Mallory Weiss tear?
this is a longitudinal tear within the gastroeosphageal mucosal junction (a lot of blood)
due to forceful, repeated retching/vomitting/coughing
describe the position of the stomach in the body?
- muscular sac that is capable of distending up to 3L
- position varies depedning on body habitus
what are the main functions of the stomach?
- food reservoir
- mechanical digestion, mixing with gastric secretions
- chemical digestion
- controlled release of contents into duodenum
- has specialised cells that contribute to secretions
- these cells tuen over rapidly (every 3-5 days)
what are the different regions of the stomach?
at what level is the transpyloric plane?
what will you find here?
L1
- pyloric sphincter
- pyloric orifice
- pyloric canal
what are the 3 layers of smooth muscle in the stomach?
- outer longitudinal
- middle circular (pyloric sphincter is a thickening of this layer)
- inner oblique
anteriorly, what is the stomach related to?
- anterior abdominal wall (Labbe’s triangle)
- left pleura, lung and diaghpram
- left lobe of the liver
posteriorly, what is the stomach related to?
- diapghram
- omental bursa/lesser sac
- spleen
- left kidney/suprarenal gland
- splenic artery and vein
- pancrease
- transverse mesocolon
describe the arterial supply of the stomach?
and the anastomes?
- all coeliac trunk branches supply the stomach either directly or via other branches.
- there is an anastomes on both curvatures
- on the lesser curvature = the left and right gastric arteries will anastomes
- on the greater curvature = the left and right gastro-omental arteries will anastomes
- there is also the short gastric artery to the fundus region which is a branch of the splenic artery
describe the venous supply of the stomach?
- all drains into the hepatic portal system
- right gastric directly into the portal vein
- right gastro-omental will join the superior mesenteric vein
- left gastric, short gastric and left gastro omental will drain into the splenic vein
describe the lympatic supply of the stomach?
there are multuple lymoh vessels around it that will all drain into the coeliac nodes, for example:
- pancreaticosplenic
- gastro omental
- gastric
- mesenteric
- pyloric nodes
what is different about the lymphatic drainage of the stomach?
it travels retrograde (it opposite direction) this is a possible source of tumour spread
describe the innervation of the stomach?
sympathetic and para sympathetic
sympathetic = from the greater splanchnic nerve T5-T9 to the celiac plexus then to the peri-arterial postsynaptic fibres
parasympathetic = from the anterior and posterior vagal trunks, with respective gastric branches
- secretomotor = promotes digestion
- afferent for emesis
where will reffered pain go to for the stomach
epigastric region
vasomotor
what is a hiatus hernia?
when the stomach protrudes through the diapghram into the mediastinum
- happens in the elderly, obese and pregnant.
what are the 2 types of hiatus hernia?
sliding = oesophageal gastric junction is above the diapghram.
- managed conservativly (weight loss, mamange GORD symptoms)
rolling = paraoesophageal, not above the diapghram.
- may cause ischamia or obstruction
- surgery may be required.
describe the small intestine and its 3 parts?
- longest section of the digestive system
- from the pylorus (stomach) to the ileoceacal valve (large intestine)
- highly folded
- main site of digestion and nutrient absorption
has three sections: - duodenum
- jejunum
- ileum
describe the duodenum?
what are its 4 parts?
C shaped
- goes from the pylorus to the duodenojejunal flexure
- retroperitoneal (except initial ampulla)
4 parts:
- superior
- descending
- horizontal
- ascending
what does the descending part of the duodenum receive?
bile and pancreatic secretions from the hepatopancreatic ampulla (this is the demarkation for the hind and forgut)
for digestion and absorption
what are the minor duodenal papilla?
The minor duodenal papilla is the opening of the accessory pancreatic duct into the descending second section of the duodenum
what vertebral levels does the duodenum cross?
L1
L2
L3
what does the suspensory ligamnet of the duodenum do?
it is a band of smooth muscle that holds the duodenum away from the diapghram
describe the arterial supply of the duodenum?
- celiac trunk and the superior mesenteric artery anastomose to supply the duodenum
- the anastomoses is called the superior and inferior pancreaticoduodenal arteries.
branches of the celiac trunk to supply the duodenum?
duodenum … common hepatic… gastroduodenal …. supraduondenal and anterior and posterior superior pancreaticoduondenal arteries.
branches of the superior mesenteric to supply the duodenum
superior mesenteric… anterior and posterior inferior pancreaticoduodenal arteries
describe the lymphatic drainage of the duodenum?
anterior and posterior drainage
- follows arteries
- anterior goes too… pancreaticoduodenal lymph nodes and pyloric
- posterior goes too… superior mesenteric lymph nodes
all will go to celiac lymph nodes
describe the innervation of the duodenum?
what does this form?
sympathetics:
- greater splanchnic (T5-T9)
- lesser splanchnic T10,T11
Parasympathetics:
- vagal trunk
this forms the coeliac and superior mesenteric plexus.
what are the different types of bariatric surgery?
surgery on the stomach
gastric bypass:
- the cardiac notch of the stomach is connected to the jejunum
adjustable gastric banding:
- adjustable band is put around the top part of the stomach (weight loss surgery)
gastric sleeve:
- removes a large portion of the stomach, removing Ghrelin cells, these are cells reposnible for hunger.
what are the pros and cons of bariatric surgery?
what is a whipple procedure?
surgery performed to remove cancerous tumours from the head of the pancreas
- gallbladder is removed
what vessel will supply the fundus region of the stomach?
short gastric
the major duodenal papilla is the site of important secretions into the duodenum, what organs contribute to these secretions?
liver
gallbladder
pancrease
The stomach has many secretions, what is the function of each:
-HCL
-mucus
- intrinsic factor
- lipase
- pepsinogen
- wide range of hormones
