20- Hepatobiliary Function Flashcards
This organ is ideally located to receive absorbed nutrients and to detoxify drugs/toxins. Its main functions include the following:
- Bile production and secretion
- Metabolism of carbohydrates, proteins, and lipids
- Bilirubin production and excretion
- Detoxification of substances
Liver
The ________ ________ _________ connects the following two capillary beds:
1) That of the abdominal and pelvic parts of the gut from the abdominal part of the esophagus to the lower anal canal, together with the pancreas, gallbladder, and spleen.
2) The hepatic sinusoidal ‘capillary’ bed.
Hepatic Portal System
What are the carbohydrate metabolism functions of the liver?
- Gluconeogenesis
- Storage of glucose as glycogen
- Release of glucose
What are the protein metabolism functions of the liver?
– Synthesis of nonessential AAs
– Modification of AA for use in biosynthetic pathways for carbohydrate
– Synthesis of almost all plasma proteins (i.e., albumin and clotting factors)
– Conversion of ammonia to urea
Liver failure can result in hypoalbuminemia, which may lead to _________.
Edema
What are the lipid metabolism functions of the liver?
- FA oxidation
- - Synthesis of lipoproteins, cholesterol, and phospholipids
This is a chronic liver disease in which normal liver cells are damaged and replaced by scar tissue. Excessive alcohol intake is a most common cause.
Cirrhosis
Alcohol abuse leads to accumulation of fat within hepatocytes. Fatty liver leads to ___________, which is fatty liver accompanied by inflammation. This leads to scarring of the liver and cirrhosis.
Steatohepatitis
Cirrhosis can cause _________ _________, which develops when there is resistance to portal blood flow, and most often occurs in the liver.
Portal Hypertension
This change to the venous circulation associated with portal hypertension is due to a swollen connection between systemic and portal systems at the inferior end of the esophagus.
Esophageal Varices
This change to the venous circulation associated with portal hypertension is due to swollen connections between systemic and portal systems around the umbilicus.
Caput Medusae
Decreased hepatic urea cycle metabolism in the context of liver cirrhosis or portosystemic shunting leads to accumulation of ammonia in the systemic circulation (hyperammonemia). Ammonia readily crosses the BBB and alters brain function and can cause __________.
Encephalopathy
This is produced and secreted by the liver, and is a vehicle for elimination of substances from the body. It also solves the insolubility problem of lipids.
Bile
What is bile composed of?
- Bile Salts (50%)
- Bile Pigments (20%; i.e., bilirubin)
- Cholesterol (4%)
- Phospholipids (40%; i.e., lecithin)
- Ions
- Water
In the hepatocytes of the liver, cholesterol reacts with 7a-hydroxylase to form the two primary bile acids. These acids are…
Cholic Acid
Chenodeoxycholic Acid
In the lumen of the small intestine, the two primary bile acids will react with 7a-dehydroxylase to form the two secondary bile acids. These acids are…
Deoxycholic Acid (from Cholic Acid) Lithocholic Acid (from Chenodeoxycholic Acid)
In the liver, the secondary bile acids will be conjugated to form bile salts. What are these bile salts?
Glycodeoxycholic Acid
Taurodeoxycholic Acid
Glycolithocholic Acid
Taurolithocholic Acid
Bile salts form _________ with the products of lipid digestion.
Micelles
Bile secretion results from the concerted actions of biliary system’s organs. These organs are…
Liver Gallbladder and Bile Duct Duodenum Ileum Portal Circulation
Bile acids and electrolytes are secreted from the liver via the bile duct. Bile is stored in the gallbladder between meals, but otherwise is taken to the _________ for emulsification and digestion of fats.
Duodenum
After emulsification and digestion of fats in the duodenum, there is micelle formation and fat absorption in the ________. After this, there is active absorption of bile acids via the ________, which then takes the bile acids back to the liver via the portal circulation.
Jejunum
Ileum
Put the following steps of the mechanism of bile secretion and absorption of bile salts in order:
A. Absorption of bile salts into the portal circulation.
B. CCK-induced gallbladder contraction and sphincter of Oddi relaxation.
C. Delivery of bile salts to the liver.
D. Synthesis and secretion of bile salts.
E. Bile salts are stored and concentrated in the gallbladder (absorption of ions and water).
1) D.
2) E.
3) B.
4) A.
5) C.
Together with newly synthesized bile acids, the returning bile acids are secreted into the ________ ________. This bile is then secreted by ductule cells in response to the osmotic effects of anion transport.
Bile Canaliculi
Secretion of bile acids is accompanied by the passive movement of _______ into the canaliculus.
Cations
Canalicular bile is primarily an ultrafiltrate of ________.
Plasma
_________ stimulates the secretion of HCO3- and H2O from the ductile cells, resulting in a significant increase in bile volume, HCO3- concentration, and pH and a decrease in the concentration of bile salts.
Secretin
Almost all bile formation is driven by bile acids (bile acid-dependent). A small portion of bile is stimulated by ________ and is secreted from the ducts (bile acid-independent or ductular secretion).
Secretin
In between meals, what happens to bile?
The gallbladder is relaxed and fills with bile, and the Sphincter of Oddi is closed.
During meals, what happens to bile?
CCK stimulates contraction of the gallbladder to release bile and causes relaxation of the Sphincter of Oddi.