Why are villi present in the intestine and not in the stomach?
The stomach is an organ exclusively used for churning and mixing the solid food with hydrochloric acid. The stomach contains folds called rugae which aid in the muscular squishing and sloshing action. Once the proteins in the food (if you are consuming meat) are broken down the pyloric sphincter opens and chyme (the broken down food) is passed into the duodenum which is the beginning of the small intestine. This area is where villi are found in the highest numbers. These are present because it allows a much higher surface area to volume ratio. In other words, more area for absorption can fit in a smaller area. Almost all the nutrients get absorbed while passing through the duodenum. Of course, bile is added to the mix which helps neutralize the stomach acid as well as help break down the lipids. Then, the food passes throughout the small intestine when the less numerous villi are present. They focus more on extracted the “left over” nutrients..Then from there, it goes to the large inte