2 - Liver

Question 1

The basic functional unit of the liver is the ______

Answer 1

lobule

Question 2

How many lobules does the average liver contain?

Answer 2

50,000 - 100,000

Question 3

The liver has ____ blood flow and _____ vascular resistance

Answer 3

high

low

Question 4

What is the blood flow per minute in the liver?

Answer 4

1350 ml/min

Question 5

What is NASH?

Answer 5

Non-alcoholic steatohepatitis

cirrhosis from excess fat accumulation in the liver and subsequent inflammation

Question 6

What is Fatty Liver Disease?

Answer 6

A less severe form of NASH

most common cause of liver disease

associated with obesity and DM2

Question 7

Why does cirrhosis cause portal HTN?

Answer 7

The vascular resistance is EXTREMELY low in the liver, and it has to be

pressure in the portal vein is usually around 9, and pressure in the hepatic vein that dumps into the vena cava is zero.

Any increase in vascular resistance in the liver will cause decreased flow through the sinusoids

Question 8

A sudden blockage of the portal vein d/t clot can lead to death within a few hours. Why?

Answer 8

excessive loss of fluid from the capillaries into the lumens and walls of the intestines

Question 9

When pressure is high in the RA, the liver can expand to hold up to _______ L of extra blood

Answer 9

0.5-1

Question 10

Compared to capillaries in other tissues, hepatic sinusoids are (more/less) permeable

Answer 10

More!

Have huge openings that even plasma proteins flow through

Question 11

Lymph draining from the liver has a protein concentration that is _______ compared to the plasma

Answer 11

almost the same as plasma

this is a testament to its extreme porosity

Question 12

How much lymph does the liver create?

Answer 12

About half the lymph in the body is from the liver

Question 13

what degree of portal hypertension can cause ascites?

Answer 13

an increase of only 3-7 mmHg

Question 14

Where does ascites come from?

Answer 14

liver sweat

excess fluid that transudes into the lumph and leaks through the outer surface of the liver capsule directly into the abdominal cavity

Pretty much pure plasma

AND

leakage from the gut wall and capillaries

Question 15

What substance is responsible for liver regeneration?

Answer 15

Hepatocyte growth factor

Question 16

Where is hepatocyte growth factor produced?

Answer 16

NOT by hepatocytes

produced by mesenchymal cells in the liver and other tissues

Blood levels of HGF spark after liver resection, but the effects are only seen in the liver

Question 17

Blood returning from the intestines is rich in colonic bacteria. How is this bacteria filtered out?

Answer 17

Kupffer cells (massive macrophages that line the hepatic sinuses)

Less than 1% of the bacteria entering the portal blood from the intestines succeeds in passing through the liver into the systemic circulation

Question 18

What are the liver’s four function in carbohydrate metabolism?

Answer 18

1. storage of large amounts of glycogen
2. conversion of galatcose and fructose to glucose
3. Gluconeogenesis
4. Formation of chemical compounds from intermediate byproduts of carb metabolism

Question 19

What is the liver’s role in fat metabolism?

Answer 19

1. Oxidation of fatty acids to supply energy
2. Synthesis of large quantities of cholesterol, phospholipids, and most lipoproteins
3. Synthesis of fat from proteins and carbs

Question 20

Describe how the liver facilitates fat use for energy

Answer 20

1. Fat is split into glycerol and fatty acids
2. fatty acids split by beta oxidation into two Acetyl CoA
3. Acetyl-CoA enters citric acid cycle
4. Whatever the liver can’t use is released into the bloodstream as acetoacetic acid
5. Tissue cells use acetoacetic acid to form acetyl CoA

Question 21

Describe how the liver facilitates fat storage

Answer 21

synthesizes fats from carbs and proteins

transported as lipoproteins

taken up by adipose tissue and stored

Question 22

What are the most important functions of the liver in protein metabolism?

Answer 22

1. deamination
2. formation of urea
3. formation of plasma proteins
4. reconversion of amino acids into other compounds

Question 23

How does the liver respond when plasma protein levels are low?

Answer 23

causes rapid mitosis of hepatic cells and growth of the liver to a larger size

Question 24

How is iron stored in the body?

Answer 24

transferred in the blood via transferrin

stored in the liver as ferritin (the product of apoferritin from the liver and iron from the blood)

This is a reversible reaction, so when iron levels are low it functions as a blood iron buffer as well as a storage medium

Question 25

In hemolytic jaundice, there is excess ______ bilirubin

In obstructive jaundice, there is excess ______ bilirubin

Why?

Answer 25

unconjugated

conjugated

In hemolytic, the liver is overwhelmed, so it can’t conjugate bilirubin fast enough

in obstructive, it actually is conjugating, the bilirubin just can’t get out and winds up bursting into the lymph

Question 26

How can you tell if jaundice is caused by conjugated or unconjugated bilirubin?

Answer 26

When an obstruction is present, no bilirubin reaches the intestines to be cnverted into urobilinogen by bacteria, and therefore there is no urobilinogen in the urine

when hemolytic processes are at fault, an excess of urobilinogen is being formed and excreted in the urine

Question 27

The liver produces all of the plasma proteins except for ____

Answer 27

immunoglobulins

Question 28

Which coagulation factors are NOT produced in hepatocytes?

Answer 28

Von Willebrand (endothelium)

Factor III (endothelium)

Factor VIII (sinusoidal cells)

Question 29

The most common indication for liver transplant is:

Answer 29

Hepatitis C

Question 30

What is the acinus of the liver?

Answer 30

Liver tissue served by a single terminal branch of the hepatic artery