The |liver| and gallbladder are responsible for a number of functions. One of the main ones relates to digestion, and the generation of digestive ~enzymes~ to be introduced into the |small intestine|. The |liver|, however, also helps control metabolism and works with the body's immune system to combat rogue cells and organisms which threaten the body (in a process called "phagocytosis"). The |liver| is the largest of the body's |glands| and is responsible for several important functions. Weighing about three pounds, the red-brown organ features a high degree of vascularity which is responsible for its dark color. Located mostly on the right side of the abdominal cavity, just above the |duodenum|, the liver |aids| in the digestion of |fats| by secreting ~bile~ into the |duodenum|. The |liver| also destroys red |blood cells|, forms ~urea~ for the excretion of nitrogenous wastes, forms fibrinogen, used in ~blood~ coagulation, stores glycogen, helps in the metabolism and storage of |vitamins|, and produces protective and antitoxic substances, among its many functions.
The gallbladder serves the function of concentrating and storing ~bile~, produced in dilute form by the |liver|, and secreting the ~bile~ through the |cystic ducts| into the |duodenum| where it can help in digestion. The gallbladder itself is a greenish organ, about three inches long, located on the underside of the |liver|. ~Bile~ is composed of ~cholesterol~, ~bile~ salts, and ~bile~ pigment. The gallbladder is not critical to the survival of the human, and may be removed without severely adverse effects. The crystallization of the ~bile~ salts in the gallbladder gives rise to ~gallstones~, which often requires surgical correction.
