Final answer:
The digestive system uses enzymes like salivary amylase and pepsin to break down carbohydrates and proteins in pizza. Chewing thoroughly is important for increasing the surface area for enzymatic action. Peristalsis moves the food through the digestive tract in the correct direction.
Step-by-step explanation:
How the Digestive System Digests a Pizza
The digestive system breaks down the carbohydrates, fats, and proteins in a pizza with cheese, pepperoni, and onions through a multi-phase process involving various enzymes. These components are digested similarly until they reach the pylorus, the passage at the lower end of the stomach.
Chewing food thoroughly is crucial as it increases the surface area for enzymes to act upon, facilitating digestion. Salivary amylase in the mouth starts breaking down carbohydrates into simple sugars. In the stomach, the enzyme pepsin begins the digestion of proteins into shorter amino acid chains.
Enzymes are essential in digestion; they are biological catalysts that speed up the biochemical reactions. For example, amylase produced in the salivary glands breaks down starch in the mouth, while pepsin, produced in the stomach, begins digesting protein. Enzymes ensure macromolecules become small enough for absorption.
Peristalsis, rhythmic contractions of the muscular wall, moves the food along the digestive tract, ensuring it moves in the right direction. The chyme is pushed through the pylorus into the small intestine, where further digestion takes place with the assistance of enzymes from the pancreas and intestinal lining, completing the breakdown into absorbable nutrients.