NEET Biology — Human Physiology

Digestion and Absorption

Have you ever wondered why you can't just rub a sandwich on your skin to get energy? Your cells are actually starving for that food, but they are too tiny to absorb it as it is. Digestion is the process of breaking down giant chunks of food into microscopic pieces that your body can actually use.

To make this journey, food must go through two distinct phases. First, digestion breaks the food down chemically and mechanically. Second, absorption moves those tiny, broken-down nutrients across your gut wall and directly into your bloodstream.

Let's follow a single bite of a sandwich. In your mouth, mechanical digestion begins as your teeth crush the bread. At the same time, chemical digestion starts as enzymes in your saliva begin to chop up complex carbohydrates.