Liver and Gallbladder Flashcards
Understand the dual blood supply of the liver and its functional significance.
The liver has a dual blood supply from the hepatic portal vein and the hepatic artery. The blood is mixed shortly before it enters the hepatic sinusoids.
The hepatic portal vein supplies approximately 75% of the liver’s blood volume. This blood is rich in nutrients and toxic materials from the intestine. This venous blood is largely depleted of oxygen.
The hepatic artery carries oxygenated blood that mixes with the venous blood just before it enters the hepatic sinusoids. It supplies approximately 25% of the liver’s blood volume.
Branches of the hepatic artery (1) and portal vein (2) travel with draining branches of the bile duct (3) forming the portal triad.
Sinusoids empty into the terminal hepatic venule (central vein). The central vein gets larger and empties into sublobular vein. The sublobular veins join to form hepatic veins.
Know how the liver acinus concept helps explain liver pathology patterns.
Liver acinus provides insights into blood perfusion, metabolic activity, and liver pathology. This concept of liver organization provides insights into blood perfusion, metabolic activity, and liver pathology.
The liver acinus is a lozenge or football shape. This concept of liver organization provides insights into blood perfusion, metabolic activity, and liver pathology. Three elliptical zones are described surrounding the short axis. Zone 1 contains the hepatocytes that are the first to receive oxygen, nutrients and toxins from the sinusoidal blood. These hepatocytes die last when circulation is impaired and are the first to regenerate. Zone 3 hepatocytes are the first to show ischemic necrosis and the first to show fat accumulation. Zone 2 hepatocytes are intermediate in character between zone 1 and 3 cells.
What cell type produces bile and plasma proteins?
Hepatocytes do this in addition to:
- Protein synthesis
- Protein storage
- Transformation of carbohydrates
- Synthesis of cholesterol, bile salts and phospholipids
- Detoxification, modification, and excretion of - exogenous and endogenous substances
- The hepatocyte also initiates formation and secretion of bile.
The adult liver secretes about 1 liter of bile a day. It consists of water, phospholipids and cholesterol, bile salts, bile pigments, and electrolytes. Bile salts such as cholic acid are emulsifying agents that aid in the digestion and absorption of lipids from the gut. About 90% of the bile salts are recycled by gut reabsorbtion, portal vein transport, and hepatocyte resecretion. Cholesterol, lecithin, electrolytes, and water are also recycled.
What cell type stores vitamin A?
Ito cells reside in the perisinusoidal space and are the primary storage site for hepatic vitamin A.
What cells border the bile canaliculi?
Small microvilli rich in ATPase and other alkaline phophatases project into the lumen of the bile canaliculi.
Which hepatocyte organelle is involved in drug detoxification?
SER is involved in drug detoxification
RER is primarily engaged in synthesis of plasma proteins
Bilirubin glucuronide gives feces their ______________.
color
Bilirubin glucuronide is a bile pigment that comes from hemoglobin breakdown. It is excreted with the feces and provides their color.
What are the functions of the gallbladder?
Gallbladder has a single duct (the cystic duct) that both receives diluted bile from the liver and discharges concentrated bile to the duodenum via the common bile duct and the sphincter of Oddi.
There are ______, ______, & ______ lobules of the liver. Describe features of each.
There are classical, portal, & acinus lobules of the liver.
The classic liver lobule is a hexagonal cylinder of tissue .The terminal hepatic venule (central vein) is at the center of the lobule.
The portal lobule emphasizes the exocrine functions of the liver. The major exocrine function is bile secretion, so the portal lobule has a portal canal at its center.
The liver acinus is a lozenge or football shape. This concept of liver organization provides insights into blood perfusion, metabolic activity, and liver pathology. Three elliptical zones are described surrounding the short axis. Zone 1 contains the hepatocytes that are the first to receive oxygen, nutrients and toxins from the sinusoidal blood. These hepatocytes die last when circulation is impaired and are the first to regenerate. Zone 3 hepatocytes are the first to show ischemic necrosis and the first to show fat accumulation. Zone 2 hepatocytes are intermediate in character between zone 1 and 3 cells.
Recognize & describe the function of hepatocyes
Cytoplasmic components of the hepatocyte are numerous reflecting the diversity of the cell’s functions.
There are numerous mitochondria. The Golgi apparatus is elaborate and each cell. Both the rough and smooth endoplasmic reticula are highly developed.
The sER varies with metabolic activity. For example, ethanol will produce sER hypertrophy. Clinically, newborns can have underdeveloped sER (neonatal hyperbilirubinemia) where bilirubin is not converted to the water-soluble bilirubin glucuronide. This is treated by blue light from ordinary fluorescent bulbs that transforms unconjugated bilirubin to a water-soluble photoisomer.
Peroxisomes and lysosomes are also numerous. Finally, glycogen in the liver provides a depot for glucose that is mobilized if blood glucose levels fall.
Recognize & describe the function of Kupffer cells
Kupffer cells are derived from monocytes and are members of the mononuclear phagocytotic system (MPS). Kupffer cells destroy aged erythrocytes (along with the spleen), digest hemoglobin, and destroy bacteria.
Recognize & describe the function of sinusoids
The hepatic sinusoids are discontinuous sinusoidal capillaries that have large fenestrae and large gaps between neighboring cells. A portion of the wall of the sinusoids is filled by Kupffer cells that also extend into the lumen (Figure 5).
Recognize & describe the function of bile ducts
A bile duct is any of a number of long tube-like structures that carry bile.
Recognize & describe the function of hepatic veins
Sinusoids empty into the terminal hepatic venule (central vein). The central vein gets larger and empties into sublobular vein. The sublobular veins join to form hepatic veins.
Recognize & describe the function of portal veins
The hepatic portal vein supplies approximately 75% of the liver’s blood volume. This blood is rich in nutrients and toxic materials from the intestine. This venous blood is largely depleted of oxygen.
