Lecture 19: GI III Flashcards
Accessory digestive organs
-liver
-gallbladder
-pancreas
-salivary glands
purpose of accessory digestive organs
-produce, store and secrete digestive enzymes and buffers
Liver
-largest visceral organ
functions of liver
- Metabolic
- Hematological
- Digestive
metabolic purpose of liver
hepatocytes regulate circulating levels of nutrients; remove metabolic waste and toxins
Hematological purpose of liver
acts as a blood resivoir, filters circulating debris
digestive purpose of liver
synthesizes and secretes bile
location of the liver
immediately inferior to the diaphragm, in the right upper abdomen. the liver sits superior and lateral to the stomach, right kidney and intestines
Surfaces of the liver
-diaphragmatic
-visceral
diaphragmatic surface of the liver
-superior and anterior surfaces, smooth and follows curve of diaphragm and body wall
Bare area of liver
area of liver in direct contact with the diaphragm, no visceral peritoneum
visceral surface of the liver
posterior and inferior surfaces, has impressions from the stomach, small intestine, right kidney, and large intestine
Lobes of the liver
-right
-left
-caudate lobe
-quadrate lobe
Ligaments of the Liver
-Falciform ligament
-coronary ligament
-right & left triangular ligaments
-round ligament
Falciform ligament
attaches liver to anterior body wall and divides the liver into L & R lobes
Coronary ligament
suspends liver from the diaphragm
R & L triangular ligaments
on superior aspect, towards lateral body wall
Round Ligament
thickening of inferior margin of falciform ligament, embryological remnant of umbilical vein
Purpose of the gallbladder
-stores and concentrates bile produced by the liver
purpose of bile
-helps in the digestion of dietary lipids through emulsification
location of the gallbladder
-hollow, pear shaped muscular sac on the right visceral surface of the liver
-lateral to stomach
-closely related to duodenum
Parts of the gallbladder (4)
- Cystic duct
- Neck
- Infundibulum
- Fundus
ducts that connect the liver and gallbladder
-R&L hepatic duct
-common hepatic duct
-cystic duct
-common bile duct
what combines to form the common hepatic duct
L&R hepatic ducts
what combines to form the common bile duct
common hepatic duct and the cystic duct
where does the common bile duct empty
duodenum
Gallbladder arterial supply
cystic artery (branch of hepatic artery proper)
Gallbladder venous drainage
cystic vein into the hepatic portal vein
contents of the porta hepatis
-hepatic portal vein
-hepatic artery proper
-common hepatic duct
what is the porta hepatis
hilium of the liver
BS & VD of the liver
BS: hepatic artery proper
VD: hepatic portal vein
origin of the artery in porta hepatis
abdominal aorta > celiac trunk > common hepatic artery > hepatic artery proper
origin of the vein in porta hepatis
union of the: SMV & splenic vein, poaterior to the pancreas form the hepatic portal vein
the hepatic portal vein carries blood from the
-small intestine
-large intestine
-stomach
-pancreas
-gallbladder
-spleen
Hepatic portal system
-connection between two capillary beds
-nutrient rich venous blood drains from the stomach and intestines and travels to the liver for processing
steps of hepatic portal system
- small intestine absorbs products of digestion
- Nutrient molecules travel in hepatic portal vein to liver
- Liver monitors blood content
- Blood enters general circulation by way of the hepatic veins, which empty into the IVC
Processing at the liver
-lobules are the functional unit of the liver
-hexagonal
-at the center of each lobule there is a central vein
at each corner theres a portal area containnig a portal triad
which direction does blood flow
toward the central vein
the portal area contains the triad of:
-a small brach of the hepatic portal vein
-a small branch of the hepatic artery proper
-a bile duct
what happens as blood flows towards the center of the portal area
hepatocytes absorb and secrete substances, altering the blood entering systemic circulation
central veins coalesce into
hepatic veins
path from hepatic veins
filteres blood passes from central veins to hepatic veins, drains into the IVC, emptying into right atrium of heart
path of alcohol consumption
- alcohol passes from the oral cavity into esophagus then stomach
- Stomach and small intestine absorb alcohol
- hepatic portal venin carries blood to liver
- enzymes metabolize alcohol in the liver
- Hepatic veins carry the blood to the IVC and go back into systemic cuirculation
what direction does bile flow
towards portal areas (opposite to blood)
what produces bile
hepatocytes
what does bile enter at edge of portal area
bile duct branch
path of bile in liver lobule
- hepatocytes produce bile
- Bile canaliculi carry bile to the bile duct of the closest portal area
- bile duct leads to the rest of the duct system
hepatic artery proper
delivers oxygenated blood to the liver
hepatic portal vein
delivers deoxygenated, but nutrient-rich blood from the digestive tract
common hepatic duct
carries bile produced by the liver away
exocrine funcitons of the pancreas
-produces digestive enzymes and alkaline buffers to neutralize acidic chyme
-duct system within pancreas carries the fluid to the duodenum
endocrine function of pancreas
-produce hormones like insulin
substance secretions exocrine vs endocrine
exocrine: substances are secreted into duct system to an epithelial surface
endocrine: susstances are secreted into interstitial fluid and then into the blood stream
appearance of pancreas
-15cm
-pink/grey colour
location of pancreas
-posterior to stomach
-head of pancrease is punched in curve of duodenum
-extends left towards the spleen
features of the pancreas
- accessory pancreatic duct
- pancreatic duct
- ucinate process
BS & VD to the pancreas
BS: branche sof the splenic artery and the pancreaticduodenal artery
VD: splenic vein
where are secretions from the gallbladder and pancreas transported
the duodenum via duct systems
fluid enters the duodenum via
papilla (major and minor)
minor papilla
only pancrease fluid enters here (from accessory pancreatic duct)
what empties into the ampulla of the duodenum at the major duodenal papilla
pancreatic duct & common bile duct
