Human Digestive System, Research Paper Example

Introduction

As one of the major human body systems, the digestive system is composed of organs, structures, and accessory glands that work together as a system to help digest food. The assessory glands “secrete digestive enzymes that are used by the digestive system to break down food substances in preparation for absorption” into the bloodstream as nutrients for other body systems and organs (Glanze, 2005, p. 371). The digestive system itself is made up of several parts with the digestive tract or musculomembranous tube extending from the mouth to the anus. The various portions of this tube includes the mouth, pharynx, esophagus, stomach, and the small and large intestines.

Key Mechanical Processes

When a person for example consumes a steak, the mechanical process involved in transporting the food through the human digestive system includes 1), the food first passes through the esophagus; 2), the food then enters the stomach where it is partially digested by stomach acids and enzymes; 3), the food then enters the small intestine via a process known as peristalsis in which digestive juices break down the food into various starches, fats, and protein, and where muscles help to move the food further down the gastrointestinal tract (GI) ; 4), the food (or waste product at this point) then enters the large intestine where water and remaining nutrients are absorbed and where waste is changed into a stool. This final part of the process involves the rectum at the far end of the large intestine where waste remains until it is expelled from the body during a bowel movement (The Digestive System and How It Works, 2013).

Mechanical v. Chemical Digestive Process

In contrast to the mechanical processes involved in the digestion of the steak, the chemical digestive process is rather complex and is of course based entirely on various chemicals and other substances that help to break down the steak into nutrients that are then used by the body for other functional purposes. First of all, enzymes or proteins that catalyzes chemical reactions via digestive juices break down the steak into different types of nutrients. One the steak is swallowed, the salivary glands “moistens the food so it moves more easily through the esophagus into the stomach” via an enzyme that breaks down starches in the steak. Second, certain glands in the stomach lining “produce stomach acid and an enzyme that digests protein;” third, the pancreas “produces a juice containing several enzymes that break down carbohydrates, fats, and proteins” and which sends digestive juices to the small intestine via ducts; fourth, the liver and the gallbladder via bile which is delivered through the bile ducts mixes with the fat and dissolves it so it can pass through the next step; fifth, the small intestine “combines with pancreatic juice and bile to complete digestion” by breaking down protein, soluble fiber, and starches through the production of “glucose molecules that absorb into the blood.” This final process is helped along by bacteria in the small intestine that also creates certain enzymes (The Digestive System and How It Works, 2013).

Food Choices and Digestive Disorders

Depending on what type of food a person consumes, such as a diet heavy in meat or conversely rich in vegetables and fruits, digestive disorders can occur, such as irritable bowel syndrome, gastroesophageal reflux, ulcers, and diverticulitis (Glanze, 2005, p. 342). In order to avoid these and other disorders of the digestive system, a person must consume a healthy and well-balanced diet. For example, irritable bowel syndrome can be avoided by consuming foods high in fiber, such as fruit, vegetables, and grain. The same holds true for gastroesophageal reflux which involves gastric juices entering the esophagus. Overall, the best way to avoid these and other disorders of the digestive system is to adhere to a diet high in vegetables, fruits, and grains as opposed to a diet high in meat, such as beef, pork, and poultry.

References

Glanze, W.D., Ed. (2005). Mosby’s Medical and Nursing Encyclopedia. St. Louis, MO: C.V. Mosby Company.

The digestive system and how it works. (2013). National Institutes of Health. Retrieved from http://digestive.niddk.nih.gov/ddiseases/pubs/yrdd