4) Processing of Drugs and Hormones : the liver can detoxify substances such as alcohol and excrete drugs such as penicillin, erythromycin, etc. into bile. It can also chemically alter or excrete thyroid hormones and steroid hormones such as estrogens and aldosterone. 5) Excretion of Bilirubin : derived from the phagocytosis of aged RBCs bilirubin is absorbed by the liver and secreted into bile. 6) Synthesis of Bile Salts : used in the small intestine for the emulsification and absorption of lipids. 7) Storage : in addition to glycogen, the liver is the storage site for vitamins A, D, E, K and B12, and minerals iron and copper which are released by the liver as needed elsewhere in the body.
8) Phagocytosis : Kupffer cells are capable of phagocytizing aged RBCs, WBCs and some bacteria.
9) Activation of Vitamin D : in addition to the skin and kidneys, the liver plays a role in the activation of vitamin D.
Small Intestine
Most digestion and absorption of nutrients occurs in the small intestine. To accommodate this, the small intestine is 25m long providing a large surface area with a 40-50L capacity. In addition, circular folds, villi, and microvilli also increase surface area.
Divided into 3 regions:
1) Duodenum
Shortest region (1 m), acts as a mixer and neutralizer (contents from stomach is pH of 2-3). Where pancreatic juices and bile enter.
2) Jejunum
About 24 m long. Absorption of some nutrients
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