The Digestive System

Summary:
           On most animals, the digestive tract is the very first thing that forms. Digestion in a human, the main key is maximizing surface area. The first part of making surface area is chewing. That breaks apart the food to allow enzymes and acids to get at them. Digesting starts in the mouth with salivary amylase that breaks down starch into glucose. Then the food goes down past the pharynx and into the esophagus then into the stomach with peristalsis. The stomach then churns the food into chyme with its gastric juices and it is very acidic. The stomach also has pepsin which breaks apart proteins. Then the small intestine has villi to have more surface area surrounded by capillaries to absorb nutrients and the small intestine has a texture like velvet. Bile is also in the small intestine and it is an emulsifier. Then the Large intestine absorbs water and salts from the chyme so you dont have constant diarrhea, and finally you poop.

Relevance to Class:
          In class, we have learned about the digestive system and specifically villi, and the idea of increasing surface area in the digestive tract. This video is a crash course explaining the general idea of of how food passes through your body. In class we learned it in much further detail, but this video does  a good job covering a general overview.

Source:
Link:  http://www.youtube.com/watch?v=s06XzaKqELk
Creator: crashcourse
Uploaded: Aug 6, 2012