Digestion
Most of our food is digested in the small intestine. The first section of the small intestine produces many digestive enzymes. Two other organs the pancreas, and the liver, release substances into the small intestine to aid digestion.
The liver produces a greenish fluid called bile, stored in the gall bladder. Bile does not contain enzymes. Bile breaks up fats into smaller droplets, bile also neutralises the acidic chyme from the stomach.
Absorption
Nutrients are absorbed into the bloodstream from the second part of the small intestine. Nutrients pass through the villi into the bloodstream.
Once absorbed into the bloodstream,. Food molecules are transported to the liver. the liver processes the nutrients, storing some and releasing others into the bloodstream to be transported to various parts of the body where they are used for growth and repair.
When food molecules are delivered to the cells they are used for energy, growth and repair. This is called assimilation.