Digestive system

The digestive system is made up of many organs that work together to turn food into essential nutrients and energy that the body can use. As a result, food usually passes through a long channel in the body known as the gastrointestinal tract (GI tract) or the alimentary canal. The gastrointestinal tract is made up of the oral cavity, the pharynx, the liver, the esophagus, and the small and large intestines (NIDDK, 2016). The digestive system also includes its own set of accessory organs, which include salivary glands, the tongue, the teeth, the pancreas, the gallbladder, and the liver. The digestive system’s primary functions include swallowing, secretion, movement and mixing, metabolism, absorption, and excretion. These functions of the digestive system depict how the food moves from the mouth and it is finally absorbed into the body.
Background information
The GI tract relates to the series of the hollow organs, which are linked by twisting and long tubes from the mouth to the anus. These hollow organs allow for the entry of the food at the mouth and the dissemination of the same at the anus (Boland, 2013). The GI tract has a bacteria regarded as the microbiome or gut flora, which aids in the digestion process. There also parts of the circulatory and nervous system that plays a significant role in the entire process of digestion.
Digestive system works by ensuring that there is movement of food via the GI tract. At the mouth, the digestion process begins with chewing. This ends later in the small intestines. The movement of food through the GI tract is characterized of a mixture of the same with digestive juices (NIDDK, 2016). As a result, the large food molecules are broken into smaller food molecules during this process. Consequently, the body has the potential of the smaller molecules absorption as the food passes through the small intestine walls in the bloodstream. The digestion waste products are eliminated via the large intestines from the body as stool.
In the mouth, the food is chewed under the saliva as the digestive juice, which helps in breaking down the starches. The esophagus facilitates in swallowing of the food. This food enters the stomach where there is stomach acid, which assists in the breaking down of the proteins. The next organ to receive the food is the small intestine, which involves the peristalsis movement and digestive juices that break down carbohydrates, protein, and starches (Boland, 2013). The pancreas has the pancreatic juice, which helps in the breaking down of proteins, fats, and starches and liver that assists in the breakdown of fats and bile acids.
The digested food molecule is absorbed in the small intestine. It is here where minerals and water are also absorbed. The absorbed food is then allowed to move to other body parts for chemical change and storage. There are specialized cells, which aid absorbed materials to pass the intestinal lining so that they can enter the bloodstream. It is in the bloodstream where simple sugars, salts, vitamins, glycerol, and amino acids are absorbed. There is also the lymphatic system, which is characterized of vessels that absorb vitamins and fatty acids into the body.
The digestive system has the role of breaking down the food. It is after the breakdown of food that such food is absorbed into the body and used in growth, cell repair, and production of the essential energy. The digestive system also has the mandate of excreting solid wastes from the body. This includes offering a good storage for the vital food elements and nutrients in the body.
In the mouth, where digestion begins, the tongue and the teeth break down the large food particles into smaller food particles (Hall, 2011). In the mouth, there are the salivary enzymes, which have the role of breaking down the starch prior to the entry of the food in the esophagus. It is the esophagus, which does the work of pushing the chewed food from the mouth all the way to the stomach. The entry of the food in the stomach is accepted by the gastric acid. Such food mixes with the gastric acid to form the chime. As the food reaches the small intestine, the bile and digestive enzymes break it prior to its entry into the large intestine. Finally, it is the work of the large intestine to ensure that electrolytes and liquid are eliminated from the food.
New information
Nerve and hormone regulators tend to control the entire process of digestive system. The small intestines and stomach have a lining of cells, which helps in the release and production of hormones that regulate the digestive system functions. It is these hormones that regulate appetite and stimulate digestive juices production (NIDDK, 2016). The intrinsic and extrinsic nerves are the ones, which are absorbed into the body that help in controlling digestive system actions. The extrinsic nerves are the ones that play the key role of ensuring that there is a connection of the organs of the digestive system to the spinal cord and the brain. The nerves release chemicals, which make GI tract to relax or contract depending on the digestion food requirement. The intrinsic nerves are found in the GI tract and tend to be triggered by the stretch of the food to the hollow organs walls. It is the nerves, which have the responsibility of releasing different substances that either delay or speed up food movement, as well as digestive juices production.
The GI tract tends to have several problems during the process of food digestion. These include abdominal pain, diarrhea, heartburn, and blood in the stool, vomiting, constipation, and challenges in swallowing, nausea, and incontinence (Guyton, 2011). These affects negative the entire process of food digestion into the body. There are also diseases of the digestive system that include the colon cancer. This cancer is caused by irregular cells and polyp growth and it is commonly diagnosed among men and women in society.
Conclusion
In conclusion, digestive system has the main role of ensuring that food is broken down into nutrients, which are absorbed into the body for cell repair, growth, and sources of energy. This occurs as the food is moved through the entire gastrointestinal (GI) tract. The digestion starts at the mouth and ends with nutrients absorption into the small intestine. The waste products of the food are eliminated from the body as solid matter after passing via the large intestines by the anus. However, there are nerve regulators and hormones, which have the role of controlling the entire process of digestion in the body. Moreover, the GI tract has several health problems and diseases, which calls for immediate medical attention if the symptoms are observed.

References
Boland, G. (2013). Gastrointestinal imaging: the requisites (4th Ed.). Philadelphia:
Elsevier/Saunders.
Hall, J. (2011). “General Principles of Gastrointestinal Function”. Guyton and Hal Textbook of
Medical Physiology (12 Ed.). Saunders Elsevier. p. 755.
Guyton, H. (2011). Textbook of Medical Physiology. U.S.: Saunders Elsevier. p. 784.
NIDDK. (2016). Your digestive system and how it works. Retrieved from:
https://www.niddk.nih.gov/health-information/health-topics/Anatomy/your-digestive-system/Pages/anatomy.aspx