Functions of the Liver

Page 1

Circulation of blood to and from the liver-

The hepatic portal vein contains low pressure deoxygenated blood that is rich in nutrients since it receives blood from the villi on the small intestine

The hepatic artery contains oxygenated blood

They deliver blood to sinusoids

The hepatic vein (low pressure deoxygenated blood) drains the blood from the sinusoids and takes it away from the liver

Page 2

Sinusoids: The Capillaries of the Liver

Sinusoids facilitate the exchange of materials between the blood and the hepatocytes.

They are composed of a single layer of endothelial cells that are slightly apart allowing direct contact between the blood and hepatocytes

Kupffer cells breakdown the haemoglobin released by older erythrocytes.

Sinusoids are unique because:

-Fenestrated

-Wider than capillaries

-A single layer of endothelial cells

-Kupffer cells

Page 3

Liver and Toxin Removal

The liver can eliminate toxins such as alcohol, herbicides and pesticides

Two cells help in this process

Kuppfer cell:

-Specialized white blood cell

-Eliminates old erythrocytes through phagocytosis

-Also eliminates Bacteria

-Contains a lot of lysosomes

Hepatocyte:

-Direct contact with the blood coming from the hepatic portal vein and hepatic artery via the sinusoids

-Absorbs the blood plasma and makes the toxins less destructive and make it water-soluble through chemical processes, so it can be expelled through urine.

Page 4

Alcohol Consumption and Liver Damage:

The alcohol is first delivered through the hepatic portal vein

If the hepatocytes weren't able to eliminate the alcohol for the first time it will come back again through the hepatic artery (cycle)

Alcohol abuse can cause:

Cirrhosis - Scar tissue formed through excessive exposure to alcohol, these locations no longer function

Fat accumulation

Inflammation

Page 5

Nutrients Stored by the Liver: