When we eat pizza, the first step in digestion is the physical breakdown of the food in the mouth. The teeth grind the pizza into smaller pieces, forming a bolus. As the bolus is being chewed, the salivary gland secretes amylase, which starts breaking down the carbohydrates in the pizza into simpler sugars.
The bolus of partially digested pizza then travels down the esophagus and into the stomach, where it is mixed with gastric juices that contain pepsin, an enzyme that helps break down proteins. The mixture of partially digested pizza and gastric juices is called chime.
The chime then moves from the stomach into the small intestine, where it is further broken down by enzymes from the liver and pancreas. The small intestine is lined with tiny finger-like projections called villi, which absorb the broken-down nutrients and pass them into the bloodstream.
Finally, the remnants of the digested pizza move into the large intestine, where water and electrolytes are absorbed, and the remaining material is eliminated as feces.
In this way, the pizza is broken down and its nutrients are absorbed and utilized by the body as it travels through the digestive system