The alimentary canal is a canal through which food travels on its way from the mouth to the anus.  It utilizes the mouth, pharynx, esophagus,stomach, intestines, and the anus. These organs are the ones that carry food through the body and expel it as waste after absorbing nutrients. These organs are the ones that directly touch and affect the food going through a persons body. This does not include the pancreas, gall bladder, or liver.
The purpose of the alimentary canal is to carry food through the body's organs that will absorb the nutrients and expel the waste. Ingestion begins the long process of fully eating and digesting our food. This process of ingesting nutrients, breaking them down for absorption, and expelling the waste and useless materials is very complicated. To begin our digestion we must first masticate the food we ingest. By chewing the food into more controllable sizes we can more easily manage these food chunks with the chemical breakdowns in the next part of our digestion. But before the chemical breakdown, we must look at the physical breakdown that the stomach does in our bodies. It churns the food, grinding it into even smaller bits, as well as dissolving the food molecules in the fluids of the digestive system. However these molecules are still too large to be absorbed into the blood. They need to be chemically changed into smaller molecules. This process can occur anywhere from in the stomach too the ends of the large intestine. For the most part, the absorption of nutrients into the blood occurs in the small intestine. If any of the substances we ingest are unable to be absorbed we simply keep moving them along our digestive tract until they are expelled. By digesting our food and absorbing these nutrients we prolong our life, give ourselves energy, and fulfill the primal needs of our bodies. 
The Alimentary canal is consisted of the; mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus. Although their are other organs that affect the digestive system, such as the gall bladder or salivary glands, they are not actually part of the alimentary canal. The first organ, the mouth, will cut, crush, and grind the food into smaller bits using the teeth. The tongue moves that food to the proper places in the mouth and is used for tasting. The pharynx and the esophagus are mainly tubes that transport the food from the neck to the next organ in the lower part of our body, the stomach. The stomach serves as a temporary storage system for the food, as well as being able to churn and secrete juices that continue to break down the food. Once the food is finished in the stomach it is then called chyme and is sent to the small intestine. Now that the chyme has reached the small intestine it will now be absorbed and digested into the blood stream because of the small intestines functions. After the chyme is completely digested by the small intestine, the large intestine takes over and begins too reabsorb the water from what is now mostly waste. After this process, the waste is turned into feces which are expelled from the body using the rectum and the anus at an appropriate time. 
Accessory Organs are the organs that aid in digestion but are not a part of the alimentary canal. These include the gall bladder, liver, and even pancreas. all of these organs help either expel waste from the body, break down the food for digestion, or filter blood to absorb nutrients. The Liver picks up many of the nutrients from the blood after the small intestine digests them out of the food. The liver also produces bile, cleans the blood, and stores the nutrients it collects. The bile that the liver secretes is a useful substance in the mechanical digestion of fats. The gall bladder stores the bile secreted by the liver and releases it into the small intestine to aid in the digestion of fats. The pancreas produces digestive fluids on its own. These fluids are secreted into the small intestine to help digest macronutrients. 
- Wile, Jay L., and Shannon, Marilyn M. The Human Body: Fearfully and Wonderfully Made!. Cincinnati: Apologia Educational Ministries, Inc., 2001. page-number. Print.
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