There are three additional organs take part in digestion of the food are the liver, the gallbladder, and the pancreas.
FUNCTION OF THE LIVER:
The liver is located in the right upper quadrant or RUQ of the abdomen. The liver creates an yellowish-brown colored or greenish, thick fluid named bile. Bile contains a fatty substance i.e. cholesterol, bile acids, and many bile pigments. The pigment named bilirubin is manufactured from the breakdown of hemoglobin in the liver. Bile combines with bilirubin in the liver and then passes into the duodenum. This material is also excreted out from the body with feces.
The bile is manufacturing continuously in the liver travels down to the gallbladder via hepatic duct and cystic duct. Gallbladder is a pear-shaped sac like structure, which is under the liver. Gallbladder collects the bile and stored inside. The bile gets concentrated in the gallbladder. The bile forced to out to the duodenum via common bile duct and pancreatic duct. The duodenum or the first part of the small intestine receives a mixture of bile and pancreatic juice.
Emulsification is an effect of bile on fats in the duodenum, by which bile breaks large fat globules and then the enzymes from the pancreas can digest the fats. So fat digestion is the important function of the bile. Without bile fat materials from the food will remain undigested. The liver apart from producing bile, which also participates many important functions in human body.
The liver maintains the amount of blood sugars also called glucose normal in the body by removing excess of sugars from the bloodstream and stores it in the form of starch (glycogen) in the liver cells.
Another important function of the liver is also to convert fats and proteins in the body into glucose and uses it when the body needs it. This process is called gluconeogenesis. The liver also produces the important blood proteins essential for blood clotting. Bilirubin is produced by the liver destruction of old erythrocytes. The liver also removes the poison materials from the blood through a process called detoxification.
The another important function of the liver is formation of urea. The liver receives amino acids from the blood and it removes ammonia and which is converted into urea, and removed by kidney and excreted out with urine.
The liver helps in the digestion of fats via bile.
The liver also helps in controlling body temperature. It stores hematrin necessary for the formation of RBCs. It forms RBC in the fetal life. It is a storehouse for many chemicals enzymes, and substances life vitamins etc.
Hepatic Portal System:
The blood vessels that bring to the liver from the intestines. This system of blood vessels is called hepatic portal system.
Digested foods pass into the portal vein directly after being absorbed into the bloodstream from the small intestine, thus giving the liver first chance at using the nutrients.
Functions of the pancreas:
The pancreas is an gland, which works both as an endocrine and also as an exocrine organ. As an exocrine, the pancreas produces pancreatic juices filled with enzymes called amylase and lipase to digest the food. These pass into the duodenum through the pancreatic duct.
As an endocrine gland, the pancreas secretes insulin into the bloodstream. Insulin is a hormone essential to help release sugar from the blood, which acts as a carrier to bring glucose into cells of the body to be used for energy.