Lecture 46 - Accessory Digestive Organs Flashcards
Differentiate the accessory organs of digestion
Liver, gallbladder, pancreas
Liver: anatomical features, relations and surface anatomy
o Heaviest gland in body
o Occupies right upper quadrant and extends to right of midline
o Deep to ribs 7-11
o Has a diaphragmatic surface in anterior, superior and posterior
o Has visceral surface inferior
o Has significant mobility with excursions of the diaphragm and with gravity
Liver: anterior aspect
o Complex diaphragmatic surface
Covered with visceral peritoneum, except posteriorly where in direct contact with diaphragm (bare area of liver)
o Right and left lobes are separated by the falciform ligament
Liver: posterior aspect
o Almost completely covered by visceral peritoneum, except in fossa for the gallbladder and porta hepatis
o Comes into contact with the oesophagus, gallbladder, stomach, duodenum, right kidney and right colic flexure & transverse colon
o Caudate and quadrate lobes can additionally be seen posteriorly
o Right & left triangular ligaments
blood supply of the liver
o Receives blood from hepatic artery (oxygenated) and hepatic portal vein (deoxygenated)
o Branches of each carry blood to hepatic sinusoids where toxins are taken up by hepatocytes
o Nutrients and hepatocyte products are secreted back into blood via hepatic vein
hepatic portal system
o Hepatic portal vein begins at L2 level
o Main vessels that contribute to hepatic portal system are
Superior mesenteric vein
Inferior mesenteric vein
Splenic vein
Pancreas; anatomical features, relations and surface anatomy
o Lies posterior to stomach, at level of L1/L2 vertebrae
o Retroperitoneal
o Extends from the duodenum to the spleen
In order of head, neck, body, tail
o Has accessory digestive and endocrine functions
Secrets digestive enzymes into small intestine
Secretes hormones (glucagon, insulin, somatostatin and pancreatic polypeptide)
pancreatic ducts
o Digestive secretions are released into small ducts that unite to form two larger ducts: pancreatic and accessory ducts
o Pancreatic duct
Begins in the tail, runs centrally through the pancreas
Joins the bile duct
o Accessory duct empties into duodenum
Spleen; anatomical features, relations and surface anatomy
o Not an accessory organ but largest lymphatic organ
o Ovoid purplish mass in the superolateral part of the left upper quadrant, protected by ribs 9-11
o Rests on left colic flexure, contacts posterior wall of stomach
Gallbladder; anatomical features, relations and surface anatomy
o Pear-shaped sac lying on the inferior surface of the liver
o Stores bile produced by liver (up to 50mL)
o Has three parts: body neck, fundus
o Very closely associated with duodenum
Arterial supply of the abdominal viscera
o 3 main branches
o Celiac trunk
o Superior mesenteric artery
o Inferior mesenteric artery
celiac trunk
o Supplies viscera in the foregut
o Stomach, duodenum, liver, gallbladder, pancreas, spleen
o Branches off at L1
o Has 3 main branches
Splenic artery
Left gastric artery
Common hepatic artery
Superior mesenteric artery
o Midgut (duodenum, jejunum, ileum, cecum, appendix, ascending colon, transverse colon)
o Branches off at L1
Inferior mesenteric artery
o Hindgut (transverse colon, descending colon, sigmoid colon, rectum)
o Branches off at L3
Other major branches of abdominal aorta
o Inferior phrenic arteries – diaphragm, inferior oesophagus
o Adrenal arteries – adrenal glands
o Renal arteries – kidneys
o Gonadal arteries – gonads (testes or ovaries)
o Lumbar arteries – vertebrae, spinal cord, abdominal wall
