Abdominal Organs 1 And 2 Lectures Flashcards
Continents of the foregut
Abdominal esophagus
Stomach
Proximal duodenum
Pancreas
Liver/gallbladder
Spleen*
*Not a gut derivative
What anatomical location separates the foregut from the midgut?
Major duodenal papilla
also site of pancreaticoduodenal branches anastomoses
Esophagogastric junction
External physiological sphincter between abdominal esophagus and cardia of stomach
When contracted food stops and prevents gastric reflux (GERD)
The Z-line of the abdominal esophagus
Marks transition in mucosa from stratified squamous to simple columnar
What attaches abdominal esophagus to the esophageal hiatus?
Phrenic-esophageal ligaments
allows breathing and eating to function separately
Parts of the pyloris
Angular notch
Pyloric canal
Pyloric sphincter
in order of closest to the body to closest to the duodenum
Chyme
Food contents mixed with gastric juices and enzymes
Minor duodenal papilla vs major duodenal papilla
Minor is above the major in the descending duodenum
Minor = accessory pancreatic duct
Major = bile and main pancreatic ducts
Hepatopancreatic ampulla
The site of bile duct and main pancreatic duct meet up right before dumping into the major duodenal papilla in the descending duodenum.
Blockage causes pancreatitis from bile moving back into pancreas
Purpose of bile
Emulsifiers fats so that intestines can absorb it.
Movement pattern of bile from liver to major duodenal papilla
Right and left hepatic ducts -> *common hepatic -> bile duct -> *hepatopancreatic ampulla -> major duodenal papilla
- common is site of gallbladder bile join via cystic duct. Hepatopancreatic is site of main pancreatic duct joining.*
Right and left triangular ligaments
Fusion of the coronary ligaments that anchor the liver to the diaphragm.
Contents of the portal triad (portal hepatis)
Hepatic proper artery
Common portal vein
Bile duct
What vein in the abdominal region does not come off directly from the IVC?
Left gonadal (testicular or ovarian)
Comes off left renal vein
Hepatic portal vein
splenic and SMV join together
Drains and filters blood from the abdominal viscera before dumping it back into the IVC
-IMV also can partake but usually comes off splenic downstream
4 collateral pathways of portal-caval anastomoses
“(Portal -> caval vein)”
Left gastric -> esophageal veins
Paraumbilical -> epigastric veins
Superior rectal -> middle and inferior rectal veins
Left Colic -> retroperitoneal veins
- All of these are possible when portal system/ liver is obstructed for any reason.
- often seen in cirrhosis of the liver
Cystohepatic triangle of Cabot is formed by what structures
Common hepatic duct
Cystic duct
Liver
site of Pringle maneuver when ligating arteries, veins and ducts during a cholecystectomy
Sympathetic innervation of the foregut
- T5-T9 presynaptic fibers leave from lateral gray horns and enter the sympathetic trunk, but DO NOT synapse.
- leave trunk via greater splanchnic and move to celiac ganglia where they synapse.
- postsynaptic fibers leave celiac ganglia and move to desired viscera and synapse there directly.
Parasympathetic innervation of foregut
Directly from vagus nerve (CN X)
Plicae circulares (valvulae conniventes)
Circular mucosal folds found throughout the jejunum and ileum (more concentrated in the jejunum)
Increase surface area of mucosa allowing increased absorption in the small intestine
Usual quadrant locations of jejunum and ileum
jejunum = LUQ
Ileum = RLQ
Peyers patches
Found in small intestine (much more common in ileum)
Monitor intestinal bacteria and prevent growth of pathogenic bacteria in intestines.
Also help prevent back flow of large intestine bacteria into small intestines.
Common physcial differences between jejunum and ileum
Jejunum:
- larger and thicker walls
- long vasa Recta w/ few arterial arcades
- less fatty mesentary
Ileum:
- smaller and thinner walls
- short vasa recta w/ many arterial arcades
- more fatty mesentary
Teniae coli
3 smooth muscle bands
aid in movement of bolus through the large intestines by contracting the haustra
Omental appendages
Fatty omental projections from teniae coli
-unknown function
Haustra
Sacculations of the large intestine wall that contract with teniae coli
Produce tonic contractions that move bolus through the large intestine
Cecum
1st part of the ascending colon
- contains illeoceal valve (not a sphincter, instead flap valve)
- also site of appendix entrance
3 main arterial anastomoses
Pancreaticoduodenal arteries
- supply collateral circulation between celiac trunk and SMA
Marginal arteries
-supply collateral circulation between SMA and IMA
Rectal arteries
-supply collateral circulation between IMA and internal iliac
Sympathetic Innervation of the midgut
T 10-12 presynaptic fibers move from lateral horn into sympathetic chain. DO NOT synapse here.
- take lesser or least splanchnic nerves out of sympathetic chain and synapse onto the superior mesenteric ganglion.
- post synaptic fibers travel to organs and viscera via the plexus where they directly synapse
Sympathetic innervation of the hindgut
L1-2 presynaptic fibers move from lateral horn to sympathetic chains and do 1 of 2 things:
- Distal 1/3 transverse colon -> superior rectum*
- DONOT synapse and exit via lumbar splanchnic nerves and synapse onto inferior mesenteric ganglion. Postsynaptic fibers then leave ganglion and travel to organs and viscera to synapse directly on them.
- inferior rectum above pectinate line*
- synapse within the chain and post sympathetic fibers exit as lumbar (3rd-5th ganglia) and sacral (1st-3rd ganglia) splanchnic nerves to supply only the middle and inferior rectum
Parasympathetic innervation of the midgut
Vagus nerve (CN X)
Parasympathetic innervation of hindgut
Pelvic splanchnic nerves (S1-2)
