Liver, Gallbladder, and Pancreas Flashcards
Liver weight
1,500g or 2.5% of adult body weight
largest internal organ and mass of glandular tissue in the body
Liver location
below the diaphragm at the upper right quadrant
Fibrous connective tissue of the liver
Glisson’s capsule
Anatomical lobes of the liver
(1) right lobe
(2) left lobe
(3) caudate lobe - upper middle
(4) quadrate lobe - lower middle
Endocrine function of the liver
What are the plasma proteins produced by the liver
1) albumin
2) glycoproteins (haptoglobin, transferrin, hemopexin)
3) fibrinogen
4) prothrombin
5) lipoproteins (VLDL, LDL, HDL)
Composition of bile
Liver stores (1) what vitamins and (2) converts them into…
- vitamin A > retinol
- vitamin D > 25-hydroxycholecalciferol
- vitamin K > prothrombin and clotting factors
- Iron > all proteins involved in transport and metabolism (transferrin, haptoglobin, and hemopexin)
Metabolic pathways performed by the liver
- carbohydrate metabolism
- glucose metabolism
- glycogenolysis
- cholesterol metabolism
- synthesizes urea
- synthesis and conversion of nonessential amino acids
carries 70% - 80% of liver blood supply
Hepatic portal vein
blood from the intestines, pancreas, and spleen; oxygen-poor but nutrient rich blood
Carries oxygen rich blood to the liver
Hepatic artery
(True/False)
Liver cells are never exposed to fully oxygenated blood
True
In liver parenchyma
(True/False)
The plates of hepatocytes in adults are 2 cell thick and separated by sinusoidal capillaries while in children they are 1 cell thick
False
The plates of hepatocytes in adults are 1 cell thick and separated by sinusoidal capillaries while in children they are 2 cell thick
Where blood vessels, nerves, lymphatics, and bile ducts travel
continuous with Glisson capsule
Connective Tissue Stroma
Vascular channels between plates of hepatocytes
Sinusoidal capillaries
aka sinusoids
space between sinusoidal epithelium and hepatocytes
perisinusoidal spaces
aka space of Disse
3 ways to describe the structure of the liver
1) classic lobule
2) portal lobule
3) liver acinus
Structural unit of the liver
Classic hepatic lobule
Consists of stacks of one cell thick plates of hepatocytes separated by sinusoids; a central venule as the terminal hepatic venule; and several portal triads surrounding the periphery
loose stromal connective tissue, continuous with the Glisson capsule and contains the portal triad, lymphatics, and nerves
Portal Space or Portal Canal
3-6 portal space per classic lobule
Site where lymph originates in the liver; a space between the connective tissue stroma and hepatocyte
Periportal space or space of Mall
Portal triad is composed of:
1) hepatic portal venule
2) hepatic arteriole
3) bile duct
Bile duct is lined by what epithelium
simple cuboidal
Hepatic arteriole carries blood from the
celiac trunk of the abdominal aorta
the hepatic portal vein comes from (1) and drains to (2)
(1) superior and inferior mesenteric vein, splenic vein
(2) central venule to the inferior vena cava
Unit of the liver that emphasizes the exocrine function of the liver
portal lobule
Formed peripherally by 3 central veins with 1 portal triad at the center
traces bile drainage to the portal triad
Portal lobule
Lozenge shaped; is the smallest functional unit of the hepatic parenchyma
Liver Acinus
Short axis is formed by 2 portal triads; Long axis is formed by 2 central veins
Basic structural component of the liver
Hepatocytes
Large polygonal cells
* nuclei are large, spherical, and centrally placed
* eosinophilic cytoplasm
* large number of mitochondria
Average lifespan of hepatocytes
5 months
(True/False)
The liver is capable of regeneration when parenchyma is damaged or lost due to hepatotoxic processes, disease, or surgery
True
What liver oxygenation zone?
- First to receive oxygen, nutrients, and toxins from sinusoidal blood
- First to show morphologic changes during bile duct occlusion or other pathologies
- Last to die if circulation is impaired
- First to regenerate
Zone 1
What liver oxygenation zone?
- First to show ischemic necrosis
- First to show fat accummulation
- Last to respond to toxic substances and bile stasis
Zone 3
Discontinuous layer of fenestrated endothelial cells
Liver sinusoids
Macrophages in sinusoids
In the luminal surface of the endothelial cells
Kupffer cells
15% of liver cell population
Fuctions to:
1) metabolize aged erythrocytes
2) digest hemoglobin
3) secrete protein related to immunologic process
4) destroy bacteria (from large intestine)
Kupffer cells
Space between the basal surfaces of hepatocytes and the basal surfaces of endothelial cells and kupffer cells that line the sinusoids
Site of exchange of materials between blood and liver cells
Perisinusoidal space or space of Disse
Fat storing cells in the space of Disse
contains vitamin A-rich lipid inclusions and type 1&3 collagen
Hepatic stellate cells
aka Ito cells
Functions to:
* uptake, storage, and release of retinoid
* synthesis and secretion of growth factors and cytokines
* regulation of the sinusoidal lumen diameter in response to different regulators (prostaglandin & thromboxane A2)
Billiary tree is lined by
Cholangiocytes
apical domain contains microvilli and a primary cilium
Biliary tree epithelium
cuboidal to columnar
Bile cannaliculi are joined by what junction
tight junctions
Consists of specific hepatic stem cells
canal of Hering
Bile produced daily
1L
2 major functions of bile
1) absorption of fat
2) excretion of cholesterol, bilirubin, iron, & copper
Regulation of bile flow
Bile flow is increased by
- cholecystokinin (CCK)
- Gastrin
- motilin
- parasympathetic stimulation
Regulation of bile flow
Bile secretion is decreased by
Estrogen
Hollow pear-shaped organ attached to the lower surface of the liver
Gallbladder
Gallbladder functions:
- store bile (30 to 50 mL)
- concentrate bile by absorbing water
- release bile
Epithelial lining of the gallbladder
simple columnar epithelium
(True/False)
Mucosal folds are always present in the gallbladder
False
mucosal folds are only present when empty
(True/False)
the wall of the gallbladder lacks muscularis mucosae and submucosa
True
Deep diverticula of the mucosa
Develop as the result of hyperplasia and herniation of epithelial cells through the muscularis externa
Rokitansky-Aschoff sinuses
Epithelial cells of the gallbladder contain what protein channel
Aquaporin 1 and 8
Final modification of bile is mainly due to
(1) active transport of Na, Cl, and HCO3
(2) passive aquaporin-mediated transport of water
Pancreas location
Retroperitoneal
at the level of the 2nd and 3rd lumbar vertebrae
Connective tissue that extends into the pancrease dividing it into ill-defined lobules
septa
The pancreatic duct of Wirsung empties into the duodenum via
hepatopancreatic ampulla (of Vater)
Regulates the flow of bile and pancreatic juice into the duodenum
prevents reflux of intestinal contents into the pancreatic duct
Hepatopancreatic sphincter (of Oddi)
pancreatic acini morphology
compound acinus gland
Formed by simple epithelium or pyramidal serous cells
(True/False)
Acinar cells are small at rest and wider during active secretion
True
Duct system of the exocrine pancreas
Acinus > intercalated ducts > intralobular duct > interlobular duct > main pancreatic duct
Most numerous in the tail region of the pancrease - endocrine portion of the pancreas
Islet of Langerhans
Major Pancreatic cells
Minor Pancreatic Cells