How the food changes consistency and form
In our digestive system, the consistency and form of the food that we intake change because of the series of processes that occur in the organs that constitute the digestive system. The food is broken down into simple nutrients that will be absorbed and eventually circulated in the body. Going back from the top, the digestion of food starts in the mouth through mastication or the mechanical digestion of food along with hydrolysis, which is the enzymatic digestion of food. This results in the reduction of food into soft, flexible, and easily swallowed form which is called the bolus. After swallowing, the bolus passes the esophagus, then into the stomach. In the stomach, churning happens, which is similar to chewing but there are more dimensions of contractions that influence the form and consistency of the food; hydrolysis is also present in the stomach. These processes transform the bolus into a more fluid type of substance called chyme. The chyme, then, moves into the small intestine where the nutrients of the food are absorbed. Lastly, in the large intestine, water, ions, and vitamin K are absorbed. When the absorption of all the needed nutrients and substances is done, feces is produced, which is ready to be expelled from the body.
How the body was able to absorb the nutrients from the foods we eat.
Absorption of the materials in our body happens through diffusion, facilitated diffusion, osmosis, and active transport. In our body, the small intestine is the host of 90% of absorption while the remaining 10% happens in the large intestine and stomach. The structure of the small intestine, which has tiny projections called villi, allows the nutrients to be absorbed into the blood. Moreover, pancreatic juice from the pancreas and the bile from the liver complete the digestion of starch, digest half of the protein, and totally carry out fat digestion and nucleic acids. Then, the absorption of water and other products occurs all along the length of the small intestine via active transport in the intestinal cell plasma membranes. In the large intestine, the substances absorbed are limited to vitamin K, some B vitamins, some ions, and water, and any undigested materials are passed onto this organ.