Liver
I. Liver
a. General Factoids of the Liver
i. The liver is the largest andocrine/exocrine gland
ii. The cells fo the liver are called hepatocytes
iii. The liver is composed of 4 lobes
iv. The liver is covered by a capsule called the capsule of glisson
1. The liver is not only covered by a capsule of glisson
2. The liver is also covered by a serosa
v. The hilum of the liver is called Porta Hepatis
vi. The liver has a dual blood supply
1. The liver receives oxygenated blood from the systemic circulation
2. The liver receives venous blood by the hepatic portal system
b. Functions of the Liver
i. The liver synthesizes
1. plasma proteins
a. Clotting factors
b. Angiotensinogen
c. Globulins
d. Lipoproteins
2. Triglycerides
a. The liver synthesizes fatty acids and cholsterols
b. The liver re-esterifies fatty acids into triglycerides
3. Glucose
a. The liver is involved with the process of the production of
glucose called gluconeogenisis
ii. The liver detoxifies
1. The liver detoxifies lipid-soluble drugs
2. The liver detoxifies ammonia into urea
iii. The liver synthesizes lipid and cholesterols
1. The liver re-esterifies fatty acids into triglycerides
iv. The liver changes bilirubin to bile
c. Hepatocytes
i. Hepatocytes are polygonal shaped
ii. Hepatocytes have a central nucleus
1. Hepatocytes are often binucleate
iii. Hepatocyte cytoplasm stain deeply basophilic due to the large presence of
rough endoplasmic reticulum
iv. Hepatocytes have microvilli
v. Adjacent hepatocytes form a union structure called the bile cannaliculi
d. Liver Lobules
i. The Liver lobules are hexagons
ii. The liver lobules contain anastmosing columns of hepatocytes
1. At the center of each liver lobule is a central vein
a. All the columns of hepatocytes radiate out from this central
vein
2. In the liver lobules, the anastomosing columns of hepatocytes are
separated by sinusoids
a. The sinusoids have kupffer cells
i. The sinusoids drain into the central veins
1. The central veins drain into hepatic veins
b. Space of Disse
i. The space of Disse is the space between the endothelial
cells of the sinusoids and the hepatocytes
iii. Hepatic Triads or Portal Triads
1. At the edges of the lobules are structures all the hepatic or portal triads
2. The hepatic or portal triads that are found at the edges of the liver
lobules in the portal canal
a. The portal canal contains 3 structures
i. Branch of the hepatic artery
ii. Branch of the portal vein
iii. Branch of the Bile Duct
e. Acinus
i. The acinus is the area of liver tissue that lies between 3 central veins.
ii. Since the acinus is the area between 3 central veins, the acinus will be situated
around the portal triads, since these are found at the edges of the lobules.
iii. The area that is bound by the acinus is divided up into 3 zones
1. Zone 1 in the acinus is the area closest to the portal traids and portal
canal area
a. Since this zone is so close to the blood supply it is the first to
regenerate, and least likely to die
2. Zone 2 is just in the middle
3. Zone 3 in the acinus is the zone closest to the central vein
a. Zone 3 of the acinus is the most vulnerable because all the bad
toxins that the liver filters has to filter through this area to get
to the central vein, and since zone is not really near the arterial
blood supply, it is more vulnerable and less likely to regenerate.