How does the food change in consistency and form?
-
Food changes in consistency and form as it travels through the digestive system. First, mechanical digestion takes place. Food mixes with saliva and is shredded by the teeth when we chew in the mouth, forming bolus, a soft and ball-like mass. This bolus travels down the esophagus and to the stomach, where it changes form once again through chemical digestion. The gastric juices in the stomach melts the bolus into chyme, a more liquid substance. As chyme moves through the intestines, the form and consistency changes once more. The small intestine absorbs the nutrients, then the large intestine absorbs the water from the chyme, producing a solid material called stool. This stool is then stored in the rectum until the appropriate time comes to excrete. To summarize, the form and consistency of food starts as itself, turned into bolus, melted into chyme, and becomes stool.
How could the body absorb the nutrients from the foods we eat?
-
The nutrient absorption from the chyme takes place in the small intestine. The small intestine is lined with finger-like projections called villi. These villi increase the surface area for transport mechanisms to absorb nutrients into the capillaries and lacteals.