Flashcards in MA - Poole Liver and Gall Bladder - 2/20 Deck (20)
What cell type produces bile and plasma proteins?
The primary digestive function of bile is to aid in the dispersion and digestion of fat in the lumen of the small intestine. Bile is formed initially in the hepatocyte (liver cell), and the rate of formation is dependent primarily on the rate at which bile acids are secreted into the bile channels, or canaliculi.
What cell type stores vitamin A?
Ito cells, which reside in the space of Disse, aka the perisinusoidal space.
In situations of chronic inflammation or cirrhosis, Ito cells lose their storage function and transform into myofibroblasts that make collagen --> fibrosis
What cells border the bile canaliculi?
The bile canaliculus is a small canal formed between the surfaces of adjacent hepatocytes. It is part of the biliary tree, tight junctions and all that.
Which hepatocyte organelle is involved in drug detoxification?
The dual blood supply to the liver first gets mixed in:
75% blood going to the liver is deoxygenated, and has waste products and whatnot, coming through the hepatic portal vein. The hepatic artery also gets 25% oxygenated blood that gets mixed just before blood enters the sinusoids.
Bilirubin glucuronide gives feces their:
Color. Bilirubin glucuronide is a bile pigment that comes from hemoglobin breakdown.
What does the concept of a liver acinus help explain?
Liver organization, which is the basis for blood flow, metabolic activities and liver pathology. The liver acinus can be drawn as a football shape between 2 liver hexagons, from middle (central vein) to middle (central vein) of each hexagon. It has 3 zones, moving outward from the center of the acinus, as 321-123.
Zone 1 has hepatocytes, the first to receive O2, nutrients and toxins. They are the first to die if perfusion is limited, and the first to regenerate if perfusion is restored.
Zone 3 had hepatocytes that are the most likely to show signs of necrosis and fat deposition. Zone 2 is in the middle, in both location and characteristics.
What layers of the small intestine are missing in the gallbladder?
The gallbladder has a mucosa, simple columnar epithelium, It also has a lamina propria, but NO muscularis mucosa, which differs from the small intestine. It does have a regular muscularis of smooth muscle that helps to empty it. Finally, it has adventitia on the liver side, and serosa on the free side.
Name the 3 major cell types that border the perisinusoidal space.
This is the site of exchange between blood and liver cells. The cell types found here are Ito cells, hepatocytes. Endothelial cells and some Kupffer cells are also found here. I'm not sure which 3 he means.
What are the functions of the gallbladder?
To hold bile and concentrate it
Dilute bile goes from liver --> common hepatic duct --> cystic duct --> gallbladder --> stored, concentrated --> cystic duct --> common bile duct --> duodenum via sphincter of Oddi
What are the components of the portal triad?
**There is also sometimes a lymphatic vessel that runs with these guys, and capillaries that can surround the group.
What are the endocrine functions of the liver?
The liver modifies the action of hormones released by other organs, ie Vitamin D, and thyroxine conversion, and produced growth hormone releasing factor.
Why does the liver oxidize and conjugate toxic substances?
To make them water soluble for safe excretion by the kidney.
The liver is responsible for synthesizing many plasma proteins such as albumin. Name 4 others.
Lipoproteins, ie VLDLs
Glycoproteins (haptoglobin, transferrin, hemopexin) involved in Fe transport
Non-immune alpha and beta-globulin
T/F: The liver is responsible for storing vitamins A, D, K and storing Fe.
How does blood flow through the liver?
Heptic sinusoids are radially spaced around the central vein, blood goes down through there to the sublobular veins to the hepatic veins to the inferior vena cava.
What are the structural components of the liver?
Parenchyma - 1-cell thick plates of hepatocytes separated by sinusoidal capillaries
Connective tissue stroma - continuous with Glissons capsule and branches into the smallest portal canals.
Sinusoidal capillaries aka sinusoids - separate plates of hepatocytes
Spaces of Disse aka perisinusoidal spaces - lie between the sinusoidal endothelium and the hepatocytes
T/F: Hepatocytes are frequently binucleate and polyploid nuclei develop with age.
What substances increase bile flow?
CCK, gastrin, motilin
Also PS stimulation