1. How does the food change in consistency and form?
During digestion, food is broken down into smaller molecules through mechanical and chemical means which changes its consistency into a more absorbable form. First, through mechanical digestion, food is cut into pieces as one chews and eventually, saliva gets into the mix which further breaks down food into a form that the body can use which is otherwise known as bolus. Second, in chemical digestion, the stomach holds the food wherein it is further broken down by strong stomach acids and enzymes into an absorbable form also known as chyme. In line with this, the small intestine continuous to breaks down food with the use of enzymes and bile produced by the pancreas and liver, respectively. In the small intestine, peristalsis also occurs wherein food moves and mixes in with digestive juices. From a solid state, food enters in the small intestine in a semi-solid state then comes out in a liquid form — water, bile, enzymes, and mucus all contributing to the change in its consistency and form. Finally, as chyme travels through the large intestine, excess water is absorbed together with bacteria and feces is formed — to be expelled by the body through the anus.
2. How could the body absorb the nutrients from the foods we eat?
In the small intestine, food, or bolus at this point, is first mixed with digestive enzymes and bile from the pancreas and liver — this all occurs in the duodenum. As food reaches the ileum, nutrients absorption occurs as the ileum is lined with millions of villi — finger-like projections known for absorbing nutrients. As each villus are connected to a mesh of capillaries, nutrients are passed into the bloodstream which then delivers them to other parts of the body.