Liver and Gallbladder Flashcards
1
Q
liver
A
- second largest organ (1,500 g)
- enclosed in Glisson’s capsule
- divided into 4 lobes-right, left, quadrate, caudate
2
Q
liver physiology
A
- synthesis of circulating plasma proteins-albumins, lipoproteins (VLDLs), glycoproteins (haptoglobin, transferrin, hemopexin), prothrombin and fibrinogen, non-immune alpha and beta globulin
- storage and conversion of several vitamins and iron- ADK
- degradation of drugs and toxins-oxidize or conjugate many water soluble drugs and toxins to make them more easily removable by the kidney
- involved in important metabolic pathways-glycogen, cholesterol, urea
- exocrine function in bile production
- endocrine like functions-modifies action of hormones released by other organs including vitamin D and thyroxine conversion and the production of growth hormone releasing factor
3
Q
blood supply to liver
A
- liver has dual blood supply from hepatic portal vein and hepatic artery
- hepatic portal vein supplies 75% of the liver’s blood, rich in nutrients and toxic materials from the intestine, blood cell breakdown products from the spleen and has endocrine secretions of the pancreas and enteroendocrine cells of the GI tract- low o2
- hepatic artery carries oxygenated blood that mixes with the venous blood just before it enters heptatic sinusoids, 25 %
- branches of the hepatic artery and portal vein travel with branches of the bile duct and form the portal triad
- hepatic sinusoids are in intimate contact-arranged around central vein
4
Q
portal triad
A
- hepatic artery, portal vein, bile duct
- in CT at angles of hexagonal liver lobule
- branches of the hepatic artery irrigate the structures in the portal canal
- lymphatic vessels and nerve brances can also be found in these portal canal areas
5
Q
central vein
A
- gets larger has it progresses along the lobule and empties into the sublobular veins which join to form hepatic veins that empty into inferior vena cava
- sublobular and hepatic veins travel alone
6
Q
liver structural components
A
- parenchyma-one cell thick plates of hepatocytes separated by sinusoidal capillaries
- CT stroma-continuous with glissons capsule and brancehs into the smallest portal canals
- sinusoidal capillaries-separates plates of hepatocytes
- perisinusoidal spaces (of Disse)-b/n sinusoidal epithelium and hepatocytes
7
Q
classic liver lobule
A
- hexagonal cylinder
- 0.7 x 2 mm
- terminal hepatic venule (central vein) at center
- have to draw lines connecting portal canals in humans, in pigs CT outlines it
8
Q
portal lobule
A
- emphasizes exocrine function of the liver
- bile secretion
- portal canal at center
- triangle formed by connecting lines between the three closest central veins
9
Q
liver acinus
A
- lozenge/football shaped
- long axis is line b/n 2 central veins
- short axis is line b/n adjacent portal canals
- insight into blood perfusion
- three zones surround short axis
- zone 1 first to receive oxygen, nutrients, and toxins, die last when circulation is impaired
- zone 3 first to show ischemic necrosis and fat accumulation
- zone 2 in between in character
10
Q
hepatic sinusoids
A
- discontinuous sinusoidal capillaries that have large fenestrae and large gaps between neighboring cells
- portion of wall filled with Kupffer cells- extend into lumen
11
Q
kupffer cells
A
- derived from monocytes
- members of mononuclear phagocytic system (MPS)
- destroy aged erythrocytes, digest hemoglobin, and destroy bacteria
- 15% of liver cell pop
12
Q
perisinusoidal space of Disse
A
- site of exchange of materials between blood and liver cells
- hepatocytes have numerous microvilli that project into this space and increase SA 6x
- ito cells in this space- store vitamin A
- chronic IF/cirrhosis- ito cells lose ability and change into myofibroblasts that synthesize collagen and leads to fibrosis
13
Q
hepatocytes
A
- large, polygonal cells with diameter 20-30 microns, about 80% of liver cell pop
- nuclei are large, spherical, and centrally located-binucleate cells and polyploid cells develop with age, adult liver has mostly tetraploid cells
- long life span-5 months, can be replaced by regeneration, lose ability as get older
14
Q
cytoplasmic components of liver cells
A
- numerous mito
- up to 50 golgi
- RER, sER, highly developed
- sER varies with metabolic activity
- underdeveloped sER- newborns-bilirubin not converted to water solube bilirubin glucuronide- blue light from fluorescent bulbs
- peroxisomes and lysosomes
- glycogen is a depot for glucose
15
Q
biliary tree
A
- bile flows from center of classic liver lobule out to gallblaldder and SI
- canaliculi empty into intrahepatic ductules (canals of Hering) within the lobule but close to portal canal- made of cuboidal epi cells and join with interlobular bile ducts
