-
How the food changes consistency and form
-
Initially, there is ingestion, which is the act of putting food and liquids into the mouth or eating. Second is the secretion, in which cells inside the GI tract and auxiliary digestive organs discharge around 7 liters of water, acid, buffers, and enzymes into the lumen or internal area of the tract each day. Third is mixing and propulsion, in which the smooth muscle in the walls of the GI tract alternately contracts and relaxes to mix food and secretions and move them into the anus. This capacity of the digestive tract to mix and transport substances along its length is known as motility. The fourth process is digestion, in which mechanical and chemical processes break food down into little molecules. In mechanical digestion, food is sliced and ground by the teeth before swallowing, and then churned by the smooth muscles of the stomach and small intestine. Thus, food molecules disintegrate and are extensively combined with digesting enzymes. Hydrolysis breaks down the big carbohydrate, lipid, protein, and nucleic acid molecules in food during chemical digestion. Absorption is the fifth component. The entry of consumed and produced fluids, ions, and digestive products into the epithelial cells that line the lumen of the gastrointestinal system. The ingested compounds enter the blood or lymph and circulate to all of the body's cells. Lastly is the defecation in which wastes, indigestible substances, bacteria, GI tract lining cells, and digested elements that were not absorbed during their transit through the digestive tract exit the body via the anus.
-
How the body was able to absorb the nutrients from the foods we eat.
-
The small intestine gets all of the food that has been digested by the stomach. Bile, pancreatic juice, and sodium bicarbonate are found in the small intestine, where they neutralize acidity and accelerate chyme breakdown. The pancreas secretes enzymes into the small intestine to break down chyme via a chemical process. The gallbladder stores bile generated by the liver.. Within the small intestine, food continues to be broken down so that the body can absorb all the nutrients it needs. The conversion of proteins to amino acids, carbohydrates to simple sugars, and fats to fatty acids and glycerol. Villi are responsible for the absorption of nutrients into the bloodstream.
Reference
Tortora, Gerard J., and Bryan Derrickson. Principles of Anatomy & Physiology. 14th edition. Danvers, MA, Wiley, 2014.