The human digestive system is a bodily process made up of many systems, organs, and substances that break down food both physically and chemically for use by the body. But what exactly is human digestion and what happens to food as it passes through the digestive system? “…[digestion] is a group of organs that work together to convert food into energy and basic nutrients to nourish the entire body” (Tim Taylor). There are three main bodily mechanisms that contribute to the digestion process. The first mechanism is the breakdown of food, the second mechanism is the process of extracting nutrients from food, and the third mechanism is excretion, or the body's natural waste system. Each mechanism uses specific body organs and chemical compounds to assist in the digestion process. Organs such as the mouth, tongue, throat, liver, esophagus, gallbladder, pancreas, small and large intestine, rectum, and anus are all critical to the digestive process. These organs and mechanisms come together to convert the food that humans eat into energy and nutrients that the body uses to sustain life and to eliminate unnecessary waste that could be harmful to the body. While removing waste from the human body may be a difficult topic to discuss, it is an important part of the digestive system because, if left in the body, this waste would eventually poison us. The digestive system is interesting, complex and really important to our daily lives. Without the digestive system, energy and nutrients vital to the body could never reach the body's cells and a person would not be able to do all the things he or she likes to do, such as studying, playing sports and going out with friends. The body uses various organs and chemicals to break down food. The breakdown of food is the focus of the paper and contains necessary nutrients, such as stomach acid and saliva. The body also uses a waste system to eliminate bad things from the body that cannot be used as nutrients or energy. Humans and all animals, from the smallest insect to the largest mammal in the world, must remove and dispose of waste from their bodies. Separate systems work on gaseous, liquid and solid waste. The excretion of waste in living things helps maintain homeostasis that supports the basic ability to survive. There are many systems in the human body, from the circulatory system which regulates blood flow throughout the body, to the nervous system and the muscular system. Each system has its specific function and purpose in the body. However, it is fair to say that the digestive system, with all its organs, enzymes, chemicals and necessary processes, is truly one of the most important systems in the human body.