Abdominal And GI tract Anatomy Flashcards
What sympathetic/visceral afferents innervate the foregut? Which dermatomes is referred pain in the foregut referred to and what region is this?
Coeliac plexus
T5-9
Epigastric region
What sympathetic/visceral afferents innervate the midgut? Which dermatomes is referred pain in the midgut referred to and what region is this?
Superior mesenteric nerve
T10-11
Umbilical region
What sympathetic/visceral afferents innervate the hindgut? Which dermatomes is referred pain in the hindgut referred to and what region is this?
Inferior mesenteric nerve
T12-L1
Pubic/Hypogastric region
What is the peritoneum?
A serous membrane which lines the abdominopelvic wall and organs
If an organ is in contact with the posterior abdominal wall, what is it known as?
Retroperitoneum
What is a double layer of peritoneum called? How many layers will it have and what forms them?
Mesentery
4 layers- parietal, visceral, visceral, parietal
The visceral peritoneum has a separate neurolymphovascular supply to the organ it covers true or false?
False - it’s closely associated so supply is the same
What is the neurolymphvascular supply of the parietal peritoneum the same as?
The abdominal pelvic wall segment it is in contact with
Abdominal aorta is retroperitoneal true or false?
True
What is located between the mesentery?
Fat, neurolymphovasculature
Where is the lesser sac? What partially separates it from the greater sac?
Posterior to wall of stomach and liver, anterior to posterior abdominal wall
What is the greater omentum attached to?
Greater omentum of the stomach, around the transverse colon to the proximal duodenum and then posterior abdominal wall
what is the transverse mesocolon, and what are its attachments and course?
Mesentery of the transverse colon which courses horizontal from anterior aspect of right kidney across descending part of duodenum to pancreas, along posterior abdominal wall
Through which opening are the greater and lesser sacs connected? Where is this located?
Epiploic foramen of Winslow, located inferior to and through the free margin of the lesser omentum
At what spinal level does the oesophagus enter the abdomen?
T10
Which parts of the mediastinum does it travel through?
Superior and posterior
What covers the oesophagus at the oesophageal hiatus?
Right crus of diaphragm
What is the: -upper 1/3 -middle 1/3 -lower 1/3 of the oesophagus supplied by?
Upper = oesophageal branch of inferior thyroid artery (from thyrocervical trunk of subclavian) Middle = oesophageal branch of thoracic aorta Inferior = oesophageal branch of left gastric from coeliac trunk
ANS to oesophagus?
Sympathetic = coeliac plexus Parasympathetic = vagus, via oesophageal plexus
Which region does the stomach lie in?
Left hypochondrium
Epigastric
Level of transpyloric plane?
L1
What are the folds of the stomach lining called? What forms them?
Rugae
Folding of mucosa and submucosa
What organ does the descending duodenum curve around?
Pancreas
The duodenum is retroperitoneal true or false?
True - some bits in contact with posterior abdominal wall
Which part of the duodenum does the ampulla of vater open into?
The descending duodenum
What is important about the major duodenal papilla?
Where the biliary system opens into duodenum
Boundary between mid- and foregut
What are the folds of the duodenal lining called? Describe them
Plicae circulares - they are complete, circular folds
The whole duodenum is supplied by the coeliac trunk true or false?
False - the distal duodenum is supplied by the superior mesenteric artery
What artery actually supplies the duodenum?
Proximal = coeliac trunk --> gastroduodenal artery --> pancreaticoduodenal artery Distal = SMA --> inferior pancreaticoduodenal artery
Venous drainage of duodenum?
SMV, splenic veins or hepatic portal vein
Which of the four parts of the duodenum are retroperitoneal?
Second half of Superior, Descending and Horizontal
Does the superior duodenum go over or under the right lobe of the liver and the gallbladder?
Under
The proximal portion of duodenum is NOT retroperitoneal, but it is covered by something… what?
Lesser omentum
Bile duct and hepatic portal vein both pass over the superior duodenum true or false?
False, they are posterior
The duodenojejunal flexure is situated to the left of the abdominal aorta true or false?
true
What organs are found posterior to the right lobe of the liver?
Right suprarenal gland, right kidney and transverse colon
What organs are found posterior to the left lobe of the liver?
Stomach and oesophagus
What separates the left lobe of the liver from the caudate lobe?
Ligamentum venosum
What separates the left lobe of the liver from the quadrate lobe?
Ligamentum teres
The ligamentum venosum is part of the falsiform ligament true or false?
False, the ligamentum teres is part of the falsiform ligament
Embryologically, what were the ligamentum venosum and teres?
LV = ductus venosus LT = umbilical vein
Function of umbilical vein embryologically?
Carry OXYgenated blood into foetus, terminating in porta hepatis (hepatic portal vein)
Function of ductus venosus embryologically?
Took blood from umbilical vein to the IVC in order to bypass porta hepatis
Venous drainage?
Right, middle and left hepatic veins –> IVC
What does the lesser omentum join?
posterior visceral surface of liver to lesser curvature of stomach (from cardiac to pylorus and a bit of duodenum)
Right edge of lesser omentum is free true or false? What structure(s) does it encapsulate as anterior peritoneum becomes posterior peritoneum?
True
Common bile duct, hepatic artery and hepatic portal vein
Is the pancreas retro- or intraperitoneal?
Retroperitoneal - entirely
Embryological development of pancreas (time and primordial structures)
Ventral and dorsal buds distal to stomach (Week 4)
Ventral bud rotates (week 6) forming entire organ
Which regions of the pancreas lie in the curvature of the duodenum?
Uncinate process (inferiorly) and head (superiorly)
Which region of the pancreas lies posterior to the duodenum?
Neck
Relation of superior mesenteric vein to regions of pancreas?
Posterior to neck, anterior to uncinate process
Where does the minor duodenal papilla open in relation to the major duodenal papilla? What is the difference in contents
Superior - only has pancreatic secretions
What organ does the body of the pancreas overly?
Left kidney
What is an annular pancreas? Complications?
Ventral bud forms ring around duodenum in development
Can cause atresia or block duodenum
Greatest proportion of total length of GI formed by large intestine true or false?
False - small intestine
What demarcates the end of the small intestine?
Ileocaecal junction
Which SI organ (J or I) has multiple arterial arcades?
Ileum
Which SI organ (J or I) has long vasa recta rather than short?
Jejunum
Which SI organ (J or I) has the thinner wall?
Ileum
Which SI organ (J or I) is intraperitoneal?
Jejunum AND ileum
How are the jejunum and ileum anchored to the posterior abdominal wall?
By mesentery
Which SI organ (J or I) has more plicae circulares?
Jejunum
Which of the 9 regions is the caecum situated in?
Right iliac
What prevents reflux of contents of caecum back into ileum?
Ileocaecal valve
Where do the taeniae coli originate and insert?
Base of vermiform appendix to rectosigmoid junction
The ascending colon lies on the anterior abdominal wall true or false?
False - posterior abdominal wall
Nerve supply to large intestine
Up to 2/3 of transverse colon:
— parasympathetic = vagus nerve (CNX)
— sympathetic = superior mesenteric ganglia (T11-L2)
Distal to 2/3 of transverse colon:
— parasympathetic = pelvic splanchnic nerves (S2-4)
— sympathetic = inferior mesenteric ganglia (T11-L2)
Dermatome for initial pain of appendicitis?
Pain after parietal peritoneum is pressed by swelling?
T10
then right lower quadrant
What level is the rectosigmoid junction?
S3 vertebra
An important muscle of faecal continence, O and I?
Puborectalis - from body of pubis slings around anorectal flexure
How many folds are there in the rectum and what are they called?
3 transverse folds
What do the teniae coli become once they reach the anorectal junction?
Outer longitudinal smooth muscle layer of rectum
What are the small pouches of fat-filled peritoneum covering the large intestine called>
Epiploic or omental appendices
Peritoneal coverings of rectum (considered in thirds)…?
First = covering anterolateral surfaces Second = covering anterior surface Third = sub-peritoneal
What is the posterior rectum in contact with?
Sacrum
Describe the type of muscle and innervation of internal anal sphincter
Circular smooth muscle continuous with SM of rectum
Sympathetic (T11-L2) = contraction
Parasympathetic (S2-4) = relaxation
Describe the type of muscle and innervation of external anal sphincter
Striated muscle - pudendal nerve S2-4