When one talks about digestive system, what body part will first appear in your mind? Stomach isn’t it? Digestion is the breakdown of food into their smallest parts so that the nutrients can be absorbed into the body. It does not only involve the stomach but also the following:
Stomach (protein digestion)
- Protein Þ Gastric juice (hydrochloric acid and pepsin) Þ amino acids
Duodenum and pancreas (first part of small intestine for carbohydrate, fat and vitamin digestion)
- Starch (carbohydrates) Þ amylase Þ maltose Þ glucose
- Sugar (carbohydrates) Þ amylase Þ sucrose Þ glucose + fructose
- Milk Þ lactase Þ lactose
- Fats Þ bile acids (bile is stored in gall bladder and produced by pancreas) Þ fatty acids and cholesterol Þ move to cells of mucosa
- Water-soluble vitamins (B and C vitamins)
- Fat-soluble vitamins (A, D, E, K vitamins) stored in the liver and fatty tissue
Jejunum and ileum (small intestine for absorption of water, salt and minerals)
It has tiny fingerlike projections called villi covering with microscopic projections called microvilli, aiding the absorption process.
Colon (large intestine for reabsorption of water and minerals)
Water and minerals are reabsorbed into the blood in the colon. Subsequently, waste material is eliminated from the rectum during defecation.