Liver (21-22)

Question 1

The liver is the largest

Answer 1

Internal organ

Question 2

It is important for metabolism of

Answer 2

Carbohydrates, protein and fat (endocrine), modification of exogenous substances (endocrine) and formation and secretion of bile (exocrine)

Question 3

Surfaces and Borders

Answer 3

Its convex diaphragmatic (anterior, superior, and partly posterior) surface is in contact with the thorax-abdominal diaphragm and the anterior body wall

It has a relatively flat visceral (postern-inferior) surface

Question 4

Anatomical Lobes

Answer 4

Large right lobe separated from smaller left lobe by the falciform ligament

Quadrate (anterior and inferior) and caudate lobes (posterior and superior) are visible on the visceral (inferior) aspect, demarcated by the sagittal fissures

Question 5

The porta hepatis

Answer 5

a transverse fissure in the middle visceral surface of the liver, is the entrance and exit for many vessels:

1. Arterial blood from the proper hepatic artery, nerve supply (autonomic fibers) and the portal vein enters the liver here
2. The hepatic ducts exit here, along with the main lymphatic drainage
3. However, venous drainage from the liver via the hepatic veins does not exit from the portal hepatic. Instead, the hepatic veins exit on the posterior aspect of the liver and empty into the IVC

Question 6

Blood Supply

Answer 6

Hepatic Portal Vein (80% of the blood supply to the liver) brings oxygen-poor blood from the GI tract.
- this blood contains nutrients and toxins from the intestines, blood cells and their breakdown products from the spleen and endocrine secretions from the pancreas and intestines

Hepatic Arteries (20% of the blood supply to the liver) brings oxygen-rich blood

Question 7

The liver is a ____________ organ

Answer 7

Parenchymatous

Question 8

About 80% of the liver tissue is

Answer 8

Parenchyma consisting of hepatocytes arranged into thin plates separated by fine blood sinusoids.

The remaining 20% is connective tissue storm

Question 9

The liver parenchyma is traditional described as the

Answer 9

Classic Lobule - considered the morphs-functional unit of the liver.
The liver consists of about 1 million such units

1. Hexagonal in cross-section. At the center of the lobule is a relatively large venule, the central vein which is the smallest tributary of the hepatic vein

Question 10

At the peripheral angle of the hexagon are

Answer 10

Portal areas- loose stroll connective tissue characterized by the presence of the portal triads.

This connective tissue ultimately continuous with the fibrous capsule of the liver.

Question 11

Each portal triad consists of

Answer 11

Terminal branches of both hepatic portal vein. hepatic artery and bile ductule

Question 12

An anastomotic system of sinusoids

Answer 12

radially arranged, connect the portal area to the central vein. The sinusoids receive mixed blood from the hepatic after and hepatic portal vein

Question 13

The sinusoids perfuse the cell with the mixed portal and arterial blood and allow

Answer 13

the hepatocytes to exercise their endocrine and exocrine roles and modify composition of blood circulating in the sinusoid

Question 14

After being modified by the hepatocytes, the mixed blood is ultimately collected in

Answer 14

the central vein

Question 15

The central veins merge

Answer 15

into large veins and ultimately form 2 or more hepatic veins that empty into the IVC

Question 16

The hepatocyte has a _________ shape

Answer 16

Polygonal shape

Question 17

Characteristics of hepatocyte

Answer 17

2 of its surfaces face the sinusoids

The other 4 sides face a neighboring hepatocyte and between the adjacent cell membranes a tiny channel called a bile canaliculus is present

A network of bile canaliculi continues through the plates of hepatocytes

Question 18

The bile flow system

Answer 18

Bile flow is centrifugal, from the region of the central vein toward the portal area (opposite blood flow)

bile canaliculus drains into bile ductules in portal triads
The bile ductules carry the bile to the interlobular (intrahepatic) bile duct (part of portal triad) which drain into the R and L hepatic ducts, the common hepatic duct and then to the duodenum via common bile duct