Liver Lobule Anatomy and Function

What is the average transit time for blood across the liver lobule?

8.4 s

What type of cells are anchored to the endothelium of the sinusoids in the liver?

Macrophages (Kupffer cells)

Where do the bile canaliculi drain into in the liver?

Intralobular bile ducts

What happens when cholecystokinin (CCK) is released?

Sphincter of Oddi relaxes Signup and view all the answers

What is the function of the spiral valves in the cystic duct?

Facilitate bile drainage Signup and view all the answers

What gives the interior of the gallbladder a honeycombed appearance?

Extensive folding of the surface Signup and view all the answers

What is the main excretory route for lipid-soluble waste products?

Bile Signup and view all the answers

Which organ is responsible for the metabolism of essentially all steroid hormones?

Liver Signup and view all the answers

What is the major class of plasma proteins NOT synthesized by the liver?

Immunoglobulins Signup and view all the answers

Which compound is responsible for the golden yellow color of bile?

Glucuronides of bilirubin and biliverdin Signup and view all the answers

What happens to the liver's synthesis of plasma proteins following blood loss?

Replaces proteins in days to weeks Signup and view all the answers

Which system can show apparent overactivity if there is liver disease?

Endocrine system Signup and view all the answers

What is the functional unit of the liver?

Acinus Signup and view all the answers

Why is the central portion of the acinus referred to as zone 1?

It is well oxygenated Signup and view all the answers

What is the approximate normal hepatic venous pressure in humans?

5 mm Hg Signup and view all the answers

What is the purpose of the arrangement that increases the turbulence of bile as it flows out of the gallbladder?

To reduce gallstone formation risk Signup and view all the answers

Where do hepatic veins drain?

Inferior vena cava Signup and view all the answers

How many acini does the human liver contain approximately?

~100,000 acini Signup and view all the answers

What is the main role of the liver in maintaining blood glucose levels in the postprandial period?

Removing excess glucose from the blood Signup and view all the answers

Which of the following is a consequence of liver failure in relation to glucose levels?

Hypoglycemia Signup and view all the answers

What is believed to be the primary driving force for the initial formation of canalicular bile?

Secretion of bile acids Signup and view all the answers

Why does cholesterol precipitate, leading to one type of gallstones?

Deviation from the bile acids: phosphatidylcholine: cholesterol ratio Signup and view all the answers

What is a key function of the liver in fat metabolism?

Supporting fatty acid oxidation for energy supply Signup and view all the answers

How does the liver contribute to cholesterol homeostasis?

By synthesizing most lipoproteins needed by the body Signup and view all the answers

What happens to bile when it flows into the gallbladder?

It becomes hypertonic Signup and view all the answers

Which type of cells in the liver are responsible for trapping and breaking down bacteria and other particulates?

Kupffer cells Signup and view all the answers

What is the average water content in hepatic bile?

97% Signup and view all the answers

What is the primary role of cytochrome P450 enzymes in hepatocytes?

Convert toxins to inactive metabolites during phase II detoxification Signup and view all the answers

Which substance forms mixed micelles with the bile acids and cholesterol in canalicular bile?

Phosphatidylcholine Signup and view all the answers

What property of osmolarity allows bile to remain isotonic despite becoming hypertonic?

Colligative property Signup and view all the answers

Why is the peripheral zone (zone 3) of the acinus least well oxygenated?

Oxygen diffusion limitation from terminal branches of hepatic arteries Signup and view all the answers

What contributes to the high permeability of hepatic sinusoids?

Large gaps between endothelial cells Signup and view all the answers

What is the primary function of the arrangement that increases the turbulence of bile from the gallbladder?

To prevent bile acid precipitation Signup and view all the answers

Why are hepatic veins different from portal veins in terms of oxygenation?

Hepatic veins receive blood from central lobular veins Signup and view all the answers

What is the significance of acinus being at the end of a vascular stalk?

It allows for oxygen-rich blood flow into the liver lobules Signup and view all the answers

What is the role of the sphincter of Oddi in the digestive system?

Prevents bile reflux into the pancreas Signup and view all the answers

What contributes to the honeycombed appearance of the interior of the gallbladder?

Surface folding of the gallbladder Signup and view all the answers

What is the function of Kupffer cells in the liver lobule?

Anchor to the endothelium and break down particulates Signup and view all the answers

Where does the common bile duct enter to release bile into the digestive system?

Duodenum at the duodenal papilla Signup and view all the answers

What leads to the relaxation of the sphincter of Oddi to allow bile flow into the duodenum?

Presence of gastric contents in the duodenum Signup and view all the answers

What is the overall purpose of the biliary system in relation to digestion and metabolism?

Facilitate fat digestion and absorption Signup and view all the answers

What causes the skin, scleras, and mucous membranes to turn yellow in jaundice?

Accumulation of free or conjugated bilirubin in the blood Signup and view all the answers

In hyperbilirubinemia due to bile duct obstruction, which type of bilirubin is predominantly elevated in the plasma?

Conjugated bilirubin Signup and view all the answers

What is actively secreted into bile across the canalicular membrane as per the text?

Bile acids, phosphatidylcholine, and cholesterol Signup and view all the answers

What happens when there is disturbed secretion of conjugated bilirubin into the bile canaliculi?

Accumulation of free bilirubin in the plasma Signup and view all the answers

Which process would lead to a rise in free bilirubin in the blood?

Decreased uptake of bilirubin into hepatic cells Signup and view all the answers

What is the yellowness observed in jaundice mainly attributed to?

Elevated levels of bilirubin in the blood Signup and view all the answers

What is the reason for the marked pressure drop along the hepatic arterioles?

Inverse relationship between hepatic arterial and portal venous blood flow Signup and view all the answers

What effect does adenosine have on the hepatic artery and portal vein?

Vasodilation only in the hepatic artery Signup and view all the answers

What happens to adenosine accumulation in the terminal arterioles when portal flow is reduced?

It accumulates Signup and view all the answers

During the postprandial period, what happens to the 'reserve' sinusoids in the liver?

They recruit more blood flow Signup and view all the answers

What is the role of adenosine in dilating the terminal arterioles?

It has a direct vasodilator effect on the terminal arterioles Signup and view all the answers

What is the primary driving force for the initial formation of canalicular bile?

Active secretion of bile acids Signup and view all the answers

What substances passively enter the bile from the plasma by diffusion?

Water, glucose, calcium, amino acids, urea Signup and view all the answers

What is the approximate ratio of bile acids: phosphatidylcholine: cholesterol in canalicular bile?

10:3:1 Signup and view all the answers

What happens to bile flows into the gallbladder when the sphincter of Oddi is closed?

Bile is concentrated by absorption of water Signup and view all the answers

Why does bile remain isotonic even though it is transiently hypertonic?

The micelles become larger due to the presence of bile acids Signup and view all the answers

Why is it important for portal pressures not to increase linearly with portal flow until all sinusoids are recruited?

To prevent fluid loss from the highly permeable liver under normal conditions Signup and view all the answers

What role does the concentration of solids play in the gallbladder bile?

Reflects the degree of concentration through water absorption Signup and view all the answers

What happens to bile secretion when the bile duct and cystic duct are clamped?

Bile secretion stops completely. Signup and view all the answers

What stimulates gallbladder contraction according to the text?

Both fatty acids and amino acids Signup and view all the answers

What increases the production of bile by enhancing the water and HCO3 − content according to the text?

Secretin Signup and view all the answers

What are substances that increase the secretion of bile known as?

Choleretics Signup and view all the answers

What happens to intra-biliary pressure when the bile duct is clamped but the cystic duct is left open?

It rises only to about 100 mm of bile in several hours. Signup and view all the answers

What is the primary role of the liver in relation to the substances absorbed across the gut wall?

Serving as the first port for most absorbed nutrients Signup and view all the answers

Which blood vessel carries blood from the intestines to the liver?

Portal vein Signup and view all the answers

What is the function of bile synthesized by the liver?

Optimizes fat absorption Signup and view all the answers

Which vessel drains blood from the liver into the inferior vena cava?

Hepatic veins Signup and view all the answers

What is extensively modified when blood percolates through hepatic sinusoids in the liver?

Hepatic Bile Signup and view all the answers

What is a key structural feature that allows the liver to conduct a wide range of critical functions?

Structural and physiologic adaptations Signup and view all the answers

What is the major excretory route for lipid-soluble waste products according to the text?

Bile Signup and view all the answers

What is the approximate daily volume of bile secretion mentioned in the text?

500 mL Signup and view all the answers

What contributes to the golden yellow color of bile according to the text?

Glucuronides of bilirubin and biliverdin Signup and view all the answers

What is the primary source of bilirubin in the body based on the text?

Hemoglobin breakdown Signup and view all the answers

Which class of plasma proteins is NOT synthesized by the liver according to the text?

Immunoglobulins Signup and view all the answers

What can liver disease potentially lead to regarding hormone systems based on the text?

Apparent overactivity of hormone systems Signup and view all the answers

What is the main reason for the marked pressure drop along the hepatic arterioles?

Accumulation of adenosine around the arterioles Signup and view all the answers

How is bilirubin transported into bile canaliculi after conjugation?

Via an active transporter known as UDP-glucuronosyl-transferase Signup and view all the answers

What contributes to the dilation of terminal arterioles in the liver?

Portal flow reduction Signup and view all the answers

What prevents fluid loss from the highly permeable liver under normal conditions?

Recruitment of 'reserve' sinusoids Signup and view all the answers

What has a direct vasodilator effect on the hepatic artery but not on the portal vein?

Adenosine Signup and view all the answers

Why do many of the sinusoids collapse in the period between meals?

'Reserve' sinusoid recruitment Signup and view all the answers

What is the enzyme responsible for conjugating bilirubin to glucuronic acid?

Glucuronyl transferase (UDP-glucuronosyl-transferase) Signup and view all the answers

Which vessel has a lower pressure compared to the pressure in the sinusoids?

Portal vein Signup and view all the answers

What happens to the majority of bilirubin glucuronide formed in the liver?

It passes via the bile ducts to the intestine Signup and view all the answers

Why is bilirubin diglucuronide more water-soluble than free bilirubin?

As a result of conjugation to glucuronic acid Signup and view all the answers

How does unconjugated bilirubin differ in permeability compared to conjugated bilirubin in the intestine?

Unconjugated bilirubin is more permeable Signup and view all the answers

Where is the enzyme glucuronyl transferase primarily located in liver cells?

Smooth endoplasmic reticulum Signup and view all the answers

Liver Lobule Anatomy and Function

Questions and Answers

What is the average transit time for blood across the liver lobule?

What type of cells are anchored to the endothelium of the sinusoids in the liver?

Where do the bile canaliculi drain into in the liver?

What happens when cholecystokinin (CCK) is released?

What is the function of the spiral valves in the cystic duct?

What gives the interior of the gallbladder a honeycombed appearance?

What is the main excretory route for lipid-soluble waste products?

Which organ is responsible for the metabolism of essentially all steroid hormones?

What is the major class of plasma proteins NOT synthesized by the liver?

Which compound is responsible for the golden yellow color of bile?

What happens to the liver's synthesis of plasma proteins following blood loss?

Which system can show apparent overactivity if there is liver disease?

What is the functional unit of the liver?

Why is the central portion of the acinus referred to as zone 1?

What is the approximate normal hepatic venous pressure in humans?

What is the purpose of the arrangement that increases the turbulence of bile as it flows out of the gallbladder?

Where do hepatic veins drain?

How many acini does the human liver contain approximately?

What is the main role of the liver in maintaining blood glucose levels in the postprandial period?

Which of the following is a consequence of liver failure in relation to glucose levels?

What is believed to be the primary driving force for the initial formation of canalicular bile?

Why does cholesterol precipitate, leading to one type of gallstones?

What is a key function of the liver in fat metabolism?

How does the liver contribute to cholesterol homeostasis?

What happens to bile when it flows into the gallbladder?

Which type of cells in the liver are responsible for trapping and breaking down bacteria and other particulates?

What is the average water content in hepatic bile?

What is the primary role of cytochrome P450 enzymes in hepatocytes?

Which substance forms mixed micelles with the bile acids and cholesterol in canalicular bile?

What property of osmolarity allows bile to remain isotonic despite becoming hypertonic?

Why is the peripheral zone (zone 3) of the acinus least well oxygenated?

What contributes to the high permeability of hepatic sinusoids?

What is the primary function of the arrangement that increases the turbulence of bile from the gallbladder?

Why are hepatic veins different from portal veins in terms of oxygenation?

What is the significance of acinus being at the end of a vascular stalk?

What is the role of the sphincter of Oddi in the digestive system?

What contributes to the honeycombed appearance of the interior of the gallbladder?

What is the function of Kupffer cells in the liver lobule?

Where does the common bile duct enter to release bile into the digestive system?

What leads to the relaxation of the sphincter of Oddi to allow bile flow into the duodenum?

What is the overall purpose of the biliary system in relation to digestion and metabolism?

What causes the skin, scleras, and mucous membranes to turn yellow in jaundice?

In hyperbilirubinemia due to bile duct obstruction, which type of bilirubin is predominantly elevated in the plasma?

What is actively secreted into bile across the canalicular membrane as per the text?

What happens when there is disturbed secretion of conjugated bilirubin into the bile canaliculi?

Which process would lead to a rise in free bilirubin in the blood?

What is the yellowness observed in jaundice mainly attributed to?

What is the reason for the marked pressure drop along the hepatic arterioles?

What effect does adenosine have on the hepatic artery and portal vein?

What happens to adenosine accumulation in the terminal arterioles when portal flow is reduced?

During the postprandial period, what happens to the 'reserve' sinusoids in the liver?

What is the role of adenosine in dilating the terminal arterioles?

What is the primary driving force for the initial formation of canalicular bile?

What substances passively enter the bile from the plasma by diffusion?

What is the approximate ratio of bile acids: phosphatidylcholine: cholesterol in canalicular bile?

What happens to bile flows into the gallbladder when the sphincter of Oddi is closed?

Why does bile remain isotonic even though it is transiently hypertonic?

Why is it important for portal pressures not to increase linearly with portal flow until all sinusoids are recruited?

What role does the concentration of solids play in the gallbladder bile?

What happens to bile secretion when the bile duct and cystic duct are clamped?

What stimulates gallbladder contraction according to the text?

What increases the production of bile by enhancing the water and HCO3 − content according to the text?

What are substances that increase the secretion of bile known as?

What happens to intra-biliary pressure when the bile duct is clamped but the cystic duct is left open?

What is the primary role of the liver in relation to the substances absorbed across the gut wall?

Which blood vessel carries blood from the intestines to the liver?

What is the function of bile synthesized by the liver?

Which vessel drains blood from the liver into the inferior vena cava?

What is extensively modified when blood percolates through hepatic sinusoids in the liver?

What is a key structural feature that allows the liver to conduct a wide range of critical functions?

What is the major excretory route for lipid-soluble waste products according to the text?

What is the approximate daily volume of bile secretion mentioned in the text?

What contributes to the golden yellow color of bile according to the text?

What is the primary source of bilirubin in the body based on the text?

Which class of plasma proteins is NOT synthesized by the liver according to the text?

What can liver disease potentially lead to regarding hormone systems based on the text?

What is the main reason for the marked pressure drop along the hepatic arterioles?

How is bilirubin transported into bile canaliculi after conjugation?