Your Digestive System

Your Digestive System

A look inside your digestive system

The digestive system is a group of organs that work together to convert food into energy, and to dispose of unused nutrients. The digestive system is made up of the digestive tract, also called the gastrointestinal (GI) tract, which stretches from the mouth to the anus, along with the liver, pancreas, and gallbladder. A series of hollow and solid organs are part of the digestive system. The hollow organs include the mouth, esophagus, stomach, small intestine, large intestine (which includes the rectum), and anus, while the solid organs include the liver, pancreas, and gallbladder.

Within the small intestine there exists tiny cells that contain hairlike projections on their surface called microvilli. When microvilla band together, they form a structure called the brush border. The function of the microvilli is to assist in the digestion and absorption of nutrients. The microvilla secrete enzymes that aid in the breakdown of proteins and sugars, thus enabling these nutrients to be more easily absorbed by the body. When the microvilli are present, the surface area of a cell greatly increases. This in turn enables greater cell absorption from the cell surface.

There are many contributors to the digestive process. Gut flora or microbiome, also known as bacteria in the GI tract, as well as parts of the nervous and circulatory systems, all assist in this process. The process of digesting foods and processing waste each day is a combination of nerves, blood, hormones, and bacteria, along with organs of the digestive system.

Your Digestive System - Parts and Names

Terms and Information

  • Enzymes are proteins that catalyze (speed up) chemical reactions in the body.
  • The molecules that are affected by enzymes are called substrates.
  • Substrate molecules temporarily bond with the enzyme at the active site to form an
    enzyme/substrate complex.
  • The enzyme bends the substrate in a way that breaks the molecule apart.
  • The result of an enzymatic reaction is a product.