Biology HL -Functions of the Liver Essay
The liver receives its blood from two main sources; the hepatic artery and the hepatic portal vein. The hepatic artery transports oxygenated blood from the left side of the heart through the aorta to the liver. The deoxygenated blood from the liver is drained back out through the hepatic vein which returns it to the vena cava. The hepatic portal vein carries nutrient rich blood from the small intestine to the liver. Its blood however, is already deoxygenated in the wall of the stomach of the intestines. Inside of the liver the liver cells, which are also known as hepatocytes are lined up in rows to form lobules. These lobules are located around the hepatic portal vein and have capillaries called sinusoids branching through them from the hepatic portal vein and hepatic artery. (P. Barker, Harry"The Liver: Anatomy and Functions." ) These capillaries or vessels are wider than normal capillaries and contain thinly layered walls that are more porous. The hepatocytes can therefore easily absorb substances as it is in close contact with the sinusoids. The presence of oxygenated blood from the hepatic artery in the sinusoids provides the hepatocytes with oxygen needed for aerobic cell respiration. The walls of the sinusoids sometimes have phagocytes called Kupffer cells stuck on them. (Burrel, John. "Click4Biology ) These small scale cells take on the responsibility to absorb damaged red blood cells.
Not only is the liver one of the biggest organs in the human body, it is also a main part of homeostasis. One of our livers key ways in doing so is by maintaining the blood glucose level. Our normal level of blood glucose is approximately 90 mg per 100cm3, and must be kept this way via the liver. The liver withdraws excess glucose from the plasma solution and either uses it for muscle respiration during exercise or stores it as glycogen in the hepatocytes. When the level of blood glucose decreases, it is...
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