Organ systems and Evolution

Digestive System

4 . Select one representative organ in this system . Describe its structure and explain how the structure relates to the specific function of the organ . Include details about the types of cells and the types of tissues

The liver is one of the major organs of the digestive system that plays an essential role in metabolism . There are two vessels that enter the liver : the hepatic portal vein which allows the passage of food that was dissolved in the small intestine and the hepatic artery which facilitates the flow of

the oxygenated blood coming from the lungs (Marieb and Hoehn , 2006 . Moreover , most of the liver is composed of cells called hepatocytes . The hepatocytes carry out the main functions of the liver such as the synthesis and storage of protein , fat metabolism , and the transformation of carbohydrates into fatty acids among others (Marieb and Hoehn , 2006 . The liver is also made up of endothelial cells which allow water and plasma proteins to pass freely and Kupfer Cells , which are reticuloendothelial cells that ingest bacteria and other foreign particles in the blood (Marieb and Hoehn 2006

5 . Name a disease associated with this organ and explain how it affects the system and human health

One of the diseases most commonly associated with the liver is cirrhosis . Basically , cirrhosis is the formation of scars on the liver tissue due to a certain long-term disease , such as hepatitis and chronic alcoholism , or injury (US National Library of Medicine and National Institutes of Health , 2008 . Since the tissue of the liver is scarred the organ is unable to perform its normal functions such as the storage of glycogen , detoxification of the blood , protein synthesis , protein storage , red blood cells decomposition , and the production of bile that helps during digestion , among others (US National Library of Medicine and National Institutes of Health , 2008 . In other words , most of the metabolic functions of the body is impaired by liver cirrhosis

References

Hoehn , K . N , and Marieb , E , N (2006 . Human Anatomy and Physiology USA : Benjamin Cummings

United States National Library of Medicine and National Institutes of Health (2008 . Cirrhosis . MedlinePlus . Retrieved April 19 , 2008 from http /www .nlm .nih .gov /medlineplus /cirrhosis .html PAGE

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Digestive System...