Anatomy of the Liver

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Questions and Answers

Where is the liver located in the body?

In the pelvic region, mostly on the right side

In the chest cavity, mostly on the left side

Immediately beneath the diaphragm, mostly on the left side

Immediately beneath the diaphragm, mostly on the right side (correct)

What is unique about the capillaries in the liver sinusoids?

They have a thick wall

They have a large fenestrae with no diaphragm or basement membrane (correct)

They have a large fenestrae with a basement membrane

They have a small diameter

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

To store glycogen

To produce bile

To engulf foreign particles and bacteria (correct)

To filter blood

What is the function of the hepatic portal vein?

To deliver absorbed nutrients from the GI tract to the liver Signup and view all the answers

Where does the blood flow after circulating through the liver capillaries?

To the inferior vena cava Signup and view all the answers

What is the percentage of cardiac output that is directed towards the liver?

25% Signup and view all the answers

What is the arrangement of hepatic plates in a liver lobule?

Around a central vein Signup and view all the answers

What opens into the sinusoids between the hepatic plates?

Hepatic artery and hepatic portal vein Signup and view all the answers

Where is bile secreted by hepatocytes initially released?

Bile canaliculi Signup and view all the answers

What is the main purpose of enterohepatic circulation?

To reabsorb substances into the bloodstream Signup and view all the answers

What is the daily production of bile by the liver?

250-1,500 ml Signup and view all the answers

What is bilirubin derived from?

Heme without iron from hemoglobin Signup and view all the answers

What happens to free bilirubin in the liver?

It is conjugated with glucuronic acid Signup and view all the answers

What is the function of urobilinogen in the small intestine?

To make feces brown Signup and view all the answers

What is the function of bile salts in the small intestine?

To emulsify fats for digestion Signup and view all the answers

What happens to substances that are not reabsorbed in the enterohepatic circulation?

They are excreted in feces Signup and view all the answers

What is the main function of emulsification in fat digestion?

To increase the surface area for lipase enzyme activity Signup and view all the answers

What is the source of lipase enzyme involved in fat digestion?

Pancreas Signup and view all the answers

What is the role of bile acids in fat digestion?

To form micelles that increase the surface area for lipase activity Signup and view all the answers

What is the polar component of bile acids responsible for?

Attracting water molecules Signup and view all the answers

What is the primary function of the liver listed in the content?

Detoxification of blood Signup and view all the answers

What is the result of lipase activity on fat molecules?

Breakdown into fatty acids Signup and view all the answers

What is the structure formed by bile acids and fat molecules?

Micelle Signup and view all the answers

What is the purpose of the micelle structure in fat digestion?

To increase the surface area for lipase activity Signup and view all the answers

What percentage of urobilinogen is absorbed by the intestines and taken back to the liver?

30-50% Signup and view all the answers

What is the purpose of some urobilinogen in the body?

To make bile Signup and view all the answers

What is the function of bile salts in the body?

To form micelles Signup and view all the answers

What is the origin of bile acids?

Cholesterol Signup and view all the answers

What is the role of bacteria in the process of urobilinogen formation?

To convert bilirubin to urobilinogen Signup and view all the answers

What is the final destination of urobilinogen in the urine?

It gives an amber color to the urine Signup and view all the answers

What is the main component of bile salts?

Bile acids conjugated with taurine Signup and view all the answers

What is the main function of the enterohepatic circulation?

To recycle bile acids Signup and view all the answers

Which of the following is NOT a way the liver removes biologically active substances?

Excreted into urine Signup and view all the answers

What is the product of gluconeogenesis in the liver?

Glucose Signup and view all the answers

What is the function of glycogenolysis in the liver?

To break down glycogen and release glucose into the blood Signup and view all the answers

Which of the following is NOT produced by the liver?

Hemoglobin Signup and view all the answers

What is the purpose of glycogenesis in the liver?

To store glucose as glycogen Signup and view all the answers

What is the liver's role in ketone production?

To convert fatty acids into ketones Signup and view all the answers

Study Notes

Liver Structure and Function

Located immediately beneath the diaphragm, mostly on the right side
Composed of hepatocytes that form hepatic plates separated by capillaries called sinusoids
Sinusoids have large fenestrae with no diaphragm or basement membrane, making them very permeable
Kupffer cells (macrophages) are also present in the sinusoids

Hepatic Portal System

Absorbed nutrients from the GI tract are delivered first to the liver via the hepatic portal vein
Veins from the pancreas, gallbladder, stomach, intestine, and spleen join with the hepatic portal vein
After circulating through liver capillaries, the blood leaves via the hepatic vein to join regular venous circulation
Hepatic artery provides about 25% of cardiac output to maintain hepatic clearance

Liver Lobules

Hepatic plates arranged with hepatic arteries, hepatic portal veins, and a central vein
Hepatic artery and hepatic portal vein open into the sinusoids between the plates
Bile secreted by hepatocytes is released into bile canaliculi, which drain into bile ducts

Enterohepatic Circulation

Involves substances metabolized in the liver, excreted into bile, and reabsorbed across the intestinal mucosa
Substances not reabsorbed are excreted in feces

Bile Production and Secretion

Liver produces 250-1,500 ml of bile per day
Bile is composed of bile pigment (bilirubin), urobilinogen, bile salts, phospholipids, cholesterol, and inorganic ions
Bile can also contain exogenous compounds removed by hepatocytes from the blood

Bile Pigment (Bilirubin)

Produced in the spleen, liver, and bone marrow from heme (minus iron) from hemoglobin
Bilirubin is not water-soluble and is carried attached to albumin in the blood
Conjugated bilirubin is secreted into the bile, where it is taken to the small intestine

Bile Salts

Made from bile acids conjugated with glycine or taurine
Bile acids are derived from cholesterol and have four polar groups on each molecule
Form micelles with polar groups toward water and nonpolar groups inward, allowing for emulsification of fats for digestion

Liver Functions

Detoxification of Blood: removes hormones, drugs, and biologically active substances through phagocytosis, excretion into bile, and chemical alteration
Metabolism of Carbohydrates and Lipids: helps balance blood glucose levels through glycogenesis, glycogenolysis, gluconeogenesis, ketogenesis, and lipogenesis
Production of Plasma Proteins: produces plasma albumin, globulins, clotting factors, and angiotensinogen

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Description

This quiz covers the structure and function of the liver, including its location, composition, and microscopic features. It also touches on the role of hepatocytes, sinusoids, and Kupffer cells.