*The nutrients in the food we eat are divided into small molecules that get absorbed in the intestine. Carbohydrates are broken down into small glucose molecules, proteins into amino acids and fats into fatty acids.*When molecules are absorbed into the cells, they split and oxidize. It releases energy, in the form of ATP, which the cells use to carry out their tasks. Examples of cellular functions may be to build proteins, produce enzymes or for muscle cells to contract a muscle.
The food we eat provides our cells with the energy they need to perform their tasks. The food contains nutrients such as carbohydrates, proteins and fats. They have to be divided into smaller molecules to be absorbed. With help of enzymes, nutrients break down in the digestive tract into small molecules that can pass through the cell membranes. Carbohydrates are divided into glucose, which can easily be transported through the intestinal wall; bonds of proteins are broken down to particles that are so small that they can also pass through membranes.
Food is absorbed in the small intestine and goes directly to the liver through the portal vein, while lymph vessels transport fat from the intestine to fat cells in the body. In that way, the fat goes directly into the blood stream without having to go through the liver.
In the digestive tract, it also produces hormones that regulate pancreatic functions and empties bile into the small intestine.
