1. How does the food change in consistency and form?
Food changes in consistency in form primarily because of the mechanical and chemical digestion of the body. It all starts with the mouth wherein food is ingested. As it is being ingested, digestion process also takes place through chewing wherein food is being broken down into smaller pieces with the help of saliva. When done, the digested travels through the esophagus. This organ propels the food through involuntary muscle contraction and relaxation until it reaches the stomach. It is further processed by the stomach by churning and turn it into chyme. Then, as it is passed through the intestines, nutrients, water, iron, and other molecules are absorbed. Those that are processed and indigestible are stored in the rectum and is disposed by the anus as feces.
2. How could the body absorb the nutrients from the foods we eat?
The jejunum and ileum in the small intestine are the main sites of nutrition absorption. It begins at the pyloric sphincter, in the lowest part of the stomach. The absorption of several nutrients, including as proteins, lipids, carbohydrates, and nucleic acids, is specialized in the small intestine. It has several different kinds of structures, such as plicae circulares, microvilli, and villi. Some of these structures are connected by a capillary network that permits nutrients to enter the bloodstream. Conversely, some of the water, ions, and bacteria are absorbed in the large intestine.