5. Abdomen 5- Oesophagus, stomach, duodenum.pptx Flashcards
Change of muscle in the oesophagus?
Upper 1/3: striated muscle as swallowing is voluntary and rapid
Lower 1/3: smooth muscle, involuntary
Middle 1/3: mixed
Cricopharyngeal sphincter:
What is it?
Function?
Indentation caused by the normal function of the cricopharyngeal sphincter between the pharynx and the oesophagus
Function:It is to prevent air being sucked into the stomach during inhalation
Superior/cervical third of oesophagus: Begins at? Arterial supply? Venous drainage? Nerve supply? Lymphatics?
Begins at C6
Arterial supply from inferior thyroid arteries
Venous drainage to brachiocephalic veins
Nerve supply from branches of the vagus nerves (recurrent laryngeal nerves)
Lymphatics drain to deep cervical nodes
Middle/thoracic third of oesophagus: Arterial supply? Venous drainage? Nerve supply? Lymphatics?
Arterial supply direct from thoracic aorta and bronchial arteries
Venous drainage to azygos system (systemic)
Nerve supply from the oesophageal plexus (vagus and sympathetic)
Lymphatics drain to tracheobronchial nodes
Inferior/ abdominal third of oesophagus: Arterial supply? Venous drainage? Nerve supply? Lymphatics?
Arterial supply from left gastric artery
Venous drainage to left gastric veins and therefore to portal vein
Nerve supply from branches of the oesophageal plexus (vagus and sympathetic)
Lymphatics drain to left gastric and coeliac nodes
What are the 4 oesophageal constrictions?
- Upper oesophageal sphincter 17cm
- Arch of aorta
- Left main bronchus at 28cm
- Diaphragm (lower oesophageal sphincter) at 43cm
Structures anterior to the oesophagus (5)
Trachea Right pulmonary artery Left main bronchus Left atrium Diaphragm
Structures posterior to the oesophagus (3)
Vertebral bodies (C6 – T12) Thoracic duct (partly) Thoracic aorta (inferiorly)
Name a structure on the RHS and LHS of the oesophagus?
Thoracic aorta lies to the left
Azygos vein lies to the right
What is the epithelium and muscle type of the oesophagus?
It is lined by stratified squamous epithelium (transport) with submucosal mucous glands (lubrication) and has smooth muscle walls
Abdominal oesophagus: Where does it enter the abdomen? Arterial supply? Venous drainage? Lymph drainage? Nervous supply?
Where does it enter the abdomen?
It passes through the right crus of diaphragm at T10 (or 7th costal cartilage), but just to the left of the midline
Arterial supply?
Arterial supply is from the left gastric artery (and inferior phrenic)
Venous drainage?
Is to the portal vein
Lymph drainage?
Is to nodes along the left gastric artery and then coeliac nodes
Nervous supply?
By the oesophageal plexus, which is both vagal (p’symp and afferent) and sympathetic
What is the cardiac orifice?
The superior opening into the stomach from oesophagus
What forms the porto-systemic or portocaval anastomosis
Submucosal veins in the oesophagus form an anastomosis between its middle and lower thirds. The middle third drains to the azygos vein that drains to the SVC (systemic). The lower third drains to the left gastric vein that drains to the portal vein. Therefore this anastomosis is between the portal and systemic circulations i.e. a porto-systemic or portocaval anastomosis
Consequence of cirrhotic liver disease
Cirrhotic liver disease raises the portal venous pressure (portal hypertension) and blood escapes via the submucosal veins in the oesophagus and in to the systemic azygos vein. Consequently the veins become dilated and tortuous: oesophageal varices
–> Which may cause fatal haemorrhage
How is reflux prevented at the lower end of the oesophagus? 3
No anatomical sphincter, physiological sphincter
Reflux is prevented by a “physiological” cardiac sphincter: 1. Contraction of the right crus of the diaphragm
- The tonic contraction of the circular layer of smooth muscle in the lower oesophagus
- The “valvular” effect of the oblique entry of the oesophagus into the stomach, augmented by the oblique muscle layer
Sphincter closure under vagal control
What does z-line is oesophagus show?
The transition from stratified squamous (oesophageal) to columnar (gastric) epithelium is visible as the Z-line
Which regions does the stomach lie in?
It lies across the epigastric region, but extending to the umbilical and left hypogastric regions
Anterior and posterior relations of the stomach
Anteriorly related to: anterior abdominal wall; left costal margin; left pleura and lung (above diaphragm); diaphragm itself; left lobe of the liver
Posteriorly related to: lesser sac; diaphragm; spleen; left suprarenal gland; upper part of left kidney; splenic artery; pancreas; transverse mesocolon; transverse colon
What are the 4 parts of the stomach?
Cardia
Fundus
Body
Pyloric part (pyloric Antrum and canal)
What happens to the circular muscle in the pyloric region?
Thicken to form the pyloric sphincter that controls the outflow of gastric contents in to the duodenum
What are rugae?
Mucosal folds
aka maganstrasse
Change to bolus in stomach?
The stomach receives and stores food and fluid, adds more fluid plus acid and enzymes to create chyme and carry out digestion
Blood supply to stomach?
The arteries are all derived from the
branches of the coeliac artery (trunk or axis)
The left gastric artery:
- Arises from the coeliac artery.
- It supplies the lower third of the
oesophagus and the proximal part of the lesser curve and adjacent body of the stomach.
The right gastric artery
- Arises from the hepatic artery at the upper border of the pylorus.
- It supplies the distal part of the lesser curve and adjacent body of the stomach.
The short gastric arteries
- Arise from the splenic artery
- Supply the fundus
The left gastro-epiploic (omental) artery
- Arises from the splenic artery
- Supply the stomach along the proximal part of the greater curvature and adjacent body
The right gastro-epiploic artery
- Arises from the gastroduodenal branch of the hepatic artery;
- Supplies stomach along the distal part of the greater curvature and adjacent body
Arteries that supply stomach?
The left gastric artery:
The right gastric artery
The short gastric arteries
The left gastro-epiploic (omental) artery
The right gastro-epiploic artery
The arteries are all derived from the
branches of the coeliac artery (trunk or axis)
Where does the gasproduodenal artery lie in relation to the duodenum?
Posterior to the first part
Venous drainage of the stomach?
4 vessels
The veins all drain into the portal circulation
1 +2. The left and right gastric veins drain directly into the portal vein
3. The right gastro-epiploic vein joins the superior mesenteric vein
4. The short gastric veins and the left gastro-epiploiac veins join the splenic vein
What is vagotomy?
Operations done to cut the vagal trunks to:
- Reduce gastric acidity and prevent ulcers
Side effect:
-Motility was also affected causing patients to suffer incredible fullness
So consequently the vagal branches were found and sectioned selectively and highly selectively, after the hepatic branches, and after those going to the pyloric sphincter (nerve of Latarget), so that sphincteric function is maintained
Stomach bed:
Formed by?
Superiorly?
Inferiorly?
Formed by the posterior wall of the lesser sac, and retroperitoneal structures between it and the posterior abdominal wall
Superiorly: part of the diaphragm (left crus), the spleen, the left suprarenal gland and upper pole of the left kidney
Inferiorly: body and tail of pancreas, transverse mesocolon, left colic flexure and the splenic artery
Duodenum: Shape? Relations? Position in peritoneum? Functions?
C shaped structure
Adjacent to the head of the pancreas
It is mainly retroperitoneal and receives the openings of the bile and pancreatic ducts
Functions are: continued digestion, especially of fats; and absorption
What occurs at the major papilla
Duodenum has 4 parts and receives the bile and pancreatic ducts together at the major papilla
1/4 part of the duodenum start?
1st or superior part begins at the pylorus and runs upward, backward and to the right, starting on the transpyloric plane at the level of the 1st lumbar vertebra
2/4 part of the duodenum start
Major papilla?
2nd or descending part runs vertically downward in front of the hilum of the right kidney on the right side of the 2nd and 3rd lumbar vertebrae
About halfway down its medial border, the bile duct and the main pancreatic duct pierce the duodenal wall at the major duodenal papilla
Other name for major papilla?
Ampulla of Vater
3/4 part of the duodenum start?
3rd or horizontal part runs horizontally to the left on the subcostal plane, passing in front of the vertebral column at L3 and following the lower margin of the head of the pancreas
4/4 part of duodenum journey?
4th or ascending part runs upward and to the left to the duodenojejunal flexure at L2
Duodenum blood supply? Upper/lower halves
The upper half is supplied by:
- Supraduodenal and gastroduodenal branches of the common hepatic artery (Coeliac trunk, foregut)
The gastroduodenal gives anterior and posterior superior pancreaticoduodenal branches
The lower half is supplied by:
- Superior mesenteric artery (midgut) that gives the Inferior pancreaticoduodenal artery, which quickly divides into anterior and posterior branches
Duodenum venous drainage?
The superior pancreaticoduodenal vein drains into the portal vein; the
inferior vein joins the superior mesenteric vein
Duodenum lymph drainage?
Coeliac and SM nodes
Duodenum nerve supply?
The nerves are derived from sympathetic greater (T5 to T9) and lesser splanchnic (T10 and 11) nerves and parasympathetic (vagus) nerves via the coeliac and superior mesenteric plexuses
(Change from foregut to midgut)
Nerves that supply foregut?
T5-9
Nerves that supply midgut?
T10-11
