1. Food is broken down into smaller molecules during the process of digestion, both chemically and physically, in order to release the nutrients and make the food more absorbable. It moves more easily down the alimentary canal and is eventually absorbed by the intestines as its consistency changes from large bite-sized pieces to chewed semi-solid paste (bolus) and finally to a fluid-like consistency (chyme). Mucus, water, bile, and enzymes all contribute to the consistency changes. The leftover food residue liquid passes through the small intestine and into the large intestine (colon) after the nutrients have been absorbed.
2. Through the gastrointestinal (GI) tract's processes of digestion and absorption, the body obtains nutrients from the food we eat. Nutrient molecules from food are broken down during digestion and subsequently absorbed into the bloodstream through the small intestine's walls. The inner lining of the small intestine contains projections called villi and microvilli that significantly increase the surface area that is available for absorption. Nutrients pass through the walls of the small intestine, which makes it possible for nutrients needed for energy, growth, and cell repair to reach all of the body's cells. Due to its ability to absorb the majority of digested food molecules, water, and minerals and transfer them to other areas of the body for storage or additional chemical transformation, the small intestine is an essential organ for the absorption of nutrients. The circulatory system transports the nutrients to other areas of the body after specialized cells assist absorbed materials in passing through the gut lining and into the circulation.
References:
Tortora, G. J., & Derrickson, B. H. (2020). Principles of Anatomy and Physiology (16th ed.). John Wiley & Sons, Inc.