The pancreas is a glandular organ in the digestive system. It lies in the upper left part of the abdomen. Pancreatic juice is secreted by the pancreas. 

Bile juice, produced by the liver, is stored in a small organ called the gall bladder. Here the bile is concentrated, before it is released into the small intestine where it helps in the digestion of fats/lipids.

The small intestine is a part of the gastrointestinal tract between the stomach and the large intestine. Most of the digestion and absorption occurs in the small intestine. The primary function of a small intestine is absorption of nutrients and minerals from the food.

Grazing animals have a large sac-like structure called rumen between the oesophagus and the small intestine. Here the food gets partially digested and is called cud. But later the cud returns to the mouth in small lumps and the animal chews it. This process is called rumination.

Amino acids are the building blocks of proteins. Proteins are large molecules made up of one or more chains of amino acids. So the breakdown of proteins will ultimately result in the formation of the same smaller units, i.e., amino acids.

Ingestion, digestion, absorption and egestion are the processes involved in digestion of a food material.
  $\bullet$ Ingestion is the consumption of food by an organism.
  $\bullet$ Digestion is the process of breaking down food by mechanical and enzymatic action in the alimentary canal into substances that can be used by the body. 
  $\bullet$ Absorption is the process by which the digested food molecules are absorbed in the small intestine.
  $\bullet$ The left over or undigested food is removed from the body through anus by the process of egestion.