The Liver

Question 1

Describe the architectural organization of the liver in terms of the classic hepatic lobule and the hepatic acinus.

Answer 1

The functional unit of the liver is the lobule. Lobules contain “Triads”: (Artery, Vein, Bile duct, (Lymphatic vessels)), Hepatocytes, Immune cells (Kupffer cells) and Sinusoids.

Question 2

What are the major functions of hepatocytes and Kupffer cells?

Answer 2

Hepatocytes:
* Carbohydrate metabolism (glycogenesis, glycogenolysis, buffer for blood glucose)
* Lipid metabolism (carbs to proteins and fats, special lipids: lipoproteins, cholesterol, and phospholipids)
* Protein metabolism (deamination of amino acids, ammonia removal through urea synthesis, formation of albumin)
* Vitamin and Iron storage (enough A for months, D and B12, iron stored as ferretin)
* Formation of coagulation factors (liver makes almost every coagulation factor, K required for prothrombin and VII, IX, and X)
* Formation of bile
Kupffer Cells
* Resident macrophages in hepatic sinusoids, removes 99% of bacteria from GIT.

Question 3

Describe the vascular system of the liver, and its role in digestive physiology and formation of lymph. What is portal hypertension and how does it lead to ascites?

Answer 3

Low pressure, low resistance, high flow. Two sets of capillaries in the splanchnic system, low pressure, low resistance. Arterial pressure and bellow-action of thorax moves blood through hepatic system. 50% of body lymph is formed in the liver. Ascites is when fluid leaks into the abdomen due to fluid leakage from hepatic sinusoids. When increased sinusoidal pressure increases lymph production ist can lead to ascites.

Question 4

Describe the structure of the intrahepatic and extrahepatic biliary systems, and the process and control of bile formation and secretion.

Question 5

List the important constituents of bile and their functions, particularly bile acids. Describe enterohepatic circulation of bile salts and explain its diagnostic significance.

Question 6

Specify the metabolic fate of heme and the formation of bilirubin.

Question 7

Describe the principles of diagnostic testing for hepatocellular disease.