Lecture 46 11/30/23

Question 1

What are the characteristics of the hepatic lobule?

Answer 1

-anatomic unit of the liver
-consists of portal triad, linear cords of hepatocytes, and central vein

Question 2

What are the functions of the liver?

Answer 2

-filtration and storage of blood
-metabolism of carbs, fats, proteins, hormones, bilirubin, and foreign materials
-formation and excretion of bile
-reabsorption of bile acids
-storage of vitamins and iron
-formulation of plasma proteins and coagulation factors

Question 3

How does the liver receive blood?

Answer 3

-hepatic artery
-portal vein

Question 4

What are the characteristics of Kupffer cells?

Answer 4

-specialized macrophages
-part of mononuclear phagocyte system
-terminate bacteria that enters liver through portal blood
-responsible for metabolism of old RBCs

Question 5

Why is it important that the liver is an expandable organ?

Answer 5

-stores excess blood when the right atrium of the heart is not functioning properly
-releases additional blood during times of acute blood loss

Question 6

Why does the liver have high lymph flow?

Answer 6

-pores in hepatic sinusoids are very permeable
-permeability allows for passage of fluid and proteins and contribution of a large volume of lymph

Question 7

What are the functions of the liver in carbohydrate metabolism?

Answer 7

-storage of glycogen
-gluconeogenesis
-conversion of galactose to glucose
-fructose metabolism
-formulation of intermediate products required for glucose metabolism

Question 8

What are the functions of the liver in fat metabolism?

Answer 8

-oxidation of fatty acids
-cholesterol, phospholipid, and lipoprotein synthesis
-synthesis of fat from protein/carbs

Question 9

What are the functions of the liver in protein metabolism?

Answer 9

-deamination of amino acids
-formation of urea for ammonia removal
-formation of plasma proteins
-interconversion of amino acids
-synthesis of other compounds from amino acids

Question 10

What are the characteristics of albumin?

Answer 10

-important plasma protein
-accounts for 50% of the substances synthesized by the liver
-contributes 80% to plasma oncotic pressure

Question 11

What are the functions of the liver in foreign material/hormone metabolism?

Answer 11

-removes excess drugs, hormones, and other substances
-excretes or alters hormones from endocrine glands
-hepatocytes express large numbers of enzymes to convert drugs, toxins, and other materials into metabolites

Question 12

Which vitamins and minerals are stored in the liver?

Answer 12

-vitamin A/retinol
-vitamin D/calciferol
-vitamin B12/cobalamin
-iron stored as ferritin

Question 13

What are the functions of the liver in coagulation factor production?

Answer 13

-produces almost all clotting factors
-produces many clotting inhibitory proteins

Question 14

Why is it important that the liver can slow/stall bile flow through the biliary system?

Answer 14

can result in decreased intestinal vitamin K absorption, leading to a vitamin K deficiency and potential problems with clotting

Question 15

What is bilirubin?

Answer 15

a product of heme metabolism

Question 16

What is heme?

Answer 16

an iron-containing compound

Question 17

What are the characteristics of hemoglobin?

Answer 17

-contains 4 heme groups
-protein in RBCs
-allows for oxygen transport

Question 18

What are the characteristics of myoglobin?

Answer 18

-contains 1 heme group
-protein in striated muscles
-serves as intracellular storage site for oxygen

Question 19

Which type of conditions can increase bilirubin formation?

Answer 19

conditions that increase the turnover rate of RBCs

Question 20

Why is it important that bilirubin has an orange-yellow color?

Answer 20

leads to the yellow appearance of icterus

Question 21

Which enzymes are involved in the generation of bilirubin?

Answer 21

-heme oxygenase
-biliverdin reductase

Question 22

What is the role of heme oxygenase?

Answer 22

convert heme into biliverdin, which is green

Question 23

What is the role of biliverdin reductase?

Answer 23

convert biliverdin into bilirubin

Question 24

What are the characteristics of bilirubin solubility and conjugation?

Answer 24

-unconjugated bilirubin is not water soluble, and circulates in the blood bound to albumin
-unconjugated bilirubin is transported to the liver
-liver removes bilirubin from plasma and conjugates bilirubin to glucuronic acid
-conjugated bilirubin is secreted in bile

Question 25

What are the characteristics of bilirubin in the intestines?

Answer 25

-bacteria remove glucuronic acid to form urobilinogen
-urobilinogen can be oxidized to urobilin, giving urine the yellow color
-urobilinogen in intestines is oxidized to stercobilin to give feces brown color

Question 26

What is the pre-hepatic cause of high blood bilirubin?

Answer 26

increased production due to RBC lysis

Question 27

What is the hepatic cause of high blood bilirubin?

Answer 27

inadequate uptake, conjugation, and/or biliary excretion

Question 28

What is the post-hepatic cause of high blood bilirubin?

Answer 28

abnormal biliary excretion of bilirubin

Question 29

What are the characteristics of bile component recycling?

Answer 29

-bile components move from the liver to the small intestine, portal vein, and back to the liver
-bile, bilirubin, toxins, and drugs can circulate between the liver and intestines

Question 30

What are the characteristics of hepatic regeneration?

Answer 30

-liver is able to restore functional tissue following injury or lobe removal
-infectious or inflammatory conditions may complicate recovery
-regenerative ability not completely understood