Chapter 38 Notes

Sections 38.1-2

The nutrients that the body needs are water, carbs, fats, proteins, vitamins and minerals. Every cell in the human body NEEDS water, b/c many of the body's processes including chemical reactions take place in water. It's important to have a balanced diet.

The digestive system includes the mouth pharynx, esophagus, stomach, small intestine, and large intestine.
The purpose of the mouth is to make the food into smaller, usable pieces. Also, digestive enzymes in your saliva helps break down the food on a molecular level. This is called chemical digestion. The function of each organ of the digestive system is to help convert food into simpler molecules that can be absorbed and used by the cells of the body.
The combined actions of the tongue and throat molecules push the clump of food down the throat. From the throat, we go to the esophagus, or food tube down to the stomach. Gravity does not cause food to travel down this tube. We know this because astronauts can eat in outer space where gravity is unpredictable and nearly non-existent. Rather, muscles in the organ push food down to the stomach.
The stomach contains acids and chemicals that break down food into usable parts. The small intestine is where the food is absorbed. The interior of the intestine is lined with villi, which look like tiny hairs. This increases the surface area so that the body can absorb LARGE amounts at once. By the time food leaves the small intestine, nearly all the nutrients have been removed and what is left is basically toxic waste. The body eliminates it through the excretory system.