Digestive Physiology in Humans

I. Introduction

The human digestive system consists of organs from the gastrointestinal tract, which is a tube that goes from the mouth to the anus. Either end of the mouth and the anus contain a lumen, which is open on each side for the external environment. Everything inside the lumen is considered to be external to the body. The organs that make up the GI tract consist of the mouth, stomach, pharynx, esophagus, large intestine, small intestine, and the anus. The human digestive system also consists of other organs that help with digestion, such as the salivary glands, teeth, liver, tongue, gallbladder, and the pancreas(Allen, Harper 2009).. The digestive system aids in ingesting food, secreting juices, moving and mixing food, breaking down food into absorbable, tiny molecules, absorbing digestive substances and molecules throughout the GI tract wall and inside the body, discharging through the anus (Tortora 2012).

There are two kinds of digestions, mechanical, and chemical digestions. Mechanical digestion is the breaking down of food into smaller pieces. It starts off in the mouth, and goes through the stomach and the small intestine. In the mouth, masticating or chewing occurs, which mechanically breaks down the food and allows it to be swallowed and travelled to the stomach. As the food reaches the stomach, the mixing of food and digestive juices occurs in until the food reaches the small intestine (Allen, Harper 2009). The mixing of food and the digestive juices makes it easier for digestion to occur. Chemical digestion is the breakdown of large molecules by the use of enzymes to break down the bond between carbohydrates lipids, and proteins. Enzymes are large protein molecules and are used to break down ...

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...one-Rose, Lambert, McKenney. HOW TO BE A FRUGIVORE: FRUIT, CARBOHYDRATES, AND DIGESTIVE PHYSIOLOGY AMONG PRIMATES AND CARNIVORA. Journal of Animal Science, 2012, Vol.90(4), pp.49-58

Carter, Chris G., Leef M., Nowak, B. Assessment of nutritional status and digestive physiology in southern bluefin tuna Thunnus maccoyii fed a modified baitfish diet. Aquaculture, June 20, 2012, Vol.350-353, p.162

Digestion. 2009. F.A.Davis Company. Taber's Cyclopedic Medical Dictionary

Digestive Physiology. Spring 2014 Protocol - Department of Biology, Zoology Laboratories. 2014. Available from: Texas Woman’s University, Denton, Texas.

Tortora, G. J. Derrickson. Principles of Anatomy and Physiology. 13th edition ed. Danvers, MA: John Wiley and Sons, Inc.2012; 1001

Reitan, KI. 2011. Digestion of lipids and carbohydrates from microalgae. Vol.42(10), pp.1530- 1538