1. How does the food change in consistency and form?
- Food changes in consistency and form through digestion which could either be mechanical or chemical. These changes occur due to the digestive system specifically in the mouth, stomach, and small intestine. During mechanical digestion, large pieces of food are broken down into smaller pieces through chewing, grinding, and churning. In chemical digestion, food is broken down into simpler substances.
- In the mouth, chewing turns food into smaller pieces, and then salivary amylase acts and breaks down carbohydrates into simple sugars. Gastric acid then breaks down proteins, and enzymes like pepsin in the stomach. Gastric lipase break down proteins and lipids. The stomach's churning motions mix food with gastric juices and other fluids. In the small intestine, pancreatic lipase breaks down lipids into fatty acids, pancreatic amylase breaks down carbohydrates into glucose, and enzymes like trypsin and chymotrypsin break down proteins into amino acids and peptides. Bile breaks down fats into fatty acid molecules. The small intestine also uses peristalsis to help with digestion.
2. How could the body absorb the nutrients from the foods we eat?
- The small intestine has three parts: the duodenum, jejunum, and ileum. It helps to further digest food coming from the stomach. It absorbs nutrients (vitamins, minerals, carbohydrates, fats, proteins) and water from food so they can be used by the body. The small intestine is part of the digestive system.
- The small intestine of the digestive system is lined with millions of finger-like projections called villi, which are connected to capillaries. This allows nutrients to pass into the bloodstream and then distributed to the body.