The functions of the digestive system are to take in food, break the food down into nutrient molecules, absorb the molecules into the bloodstream, and to get rid of any indigestible remains. All of these functions take place as they go through the steps of the digestive system. 

The first step of the digestive system is ingestion, which is done through eating. Ingestion is where food is taken from the mouth into the alimentary canal. The alimentary canal is the digestive tube from the mouth to the anus. While in the alimentary canal, the food is chewed and mixed with saliva that contains enzymes to break down the carbohydrates and lipids. 

The second step of the digestive system is propulsion, which is the movement of food through the digestive tract and it includes both swallowing and the involuntary process of peristalsis. Peristalsis consists of sequential, alternating waves of contraction and relaxation of alimentary wall smooth muscles, which acts to propel food along and plays a role in mixing food with digestive juices. 

The third step is mechanical digestion which is a physical process that does not change the chemical nature of the food. During mechanical digestion, the food gets smaller to increase surface area and mobility. In the beginning of digestion, this happens by chewing and tongue movements that help break food into smaller bits and mixes food with saliva. During mechanical churning of food in the stomach, it breaks the food apart even more to create an acidic “soup”, which is called chyme. Segmentation consists of localized contractions of circular muscle of the muscular layer of the alimentary canal. The contractions isolate small sections of the small intestine and moves the contents back and forth to continue subdividing, breaking up, and mixing the contents. In the intestinal lumen, segmentation mixes food and digestive juices which then facilitates absorption of the food. 

The fourth step is chemical digestion, this starts in the mouth where digestive secretions break down complex food molecules into chemical building blocks. The chemical digestion is completed in the small intestine where the secretion compositions could contain water, enzymes, acids, and salts. 

The fifth step is absorption, which is where the food that has been broken down, now enters the bloodstream and puts its nutrients to work. Absorption takes place mostly in the small intestine, where most nutrients are absorbed from the lumen of the alimentary canal into the bloodstream and through the epithelial cells that make up the mucosa. 

The sixth and final step is defecation, which is where we get rid of indigestible remains. These indigestible remains, are removed from the body, through the anus, as feces. 

GERD or gastroesophageal reflux disease is a condition of the digestive system in which the reflux of gastric contents, that are going into the esophagus results in symptoms and/or complications. The most common symptoms from GERD include heartburn and regurgitation. The symptoms may be worse since GERD can cause a decrease in salivary production. GERD interferes with the mechanical digestion step of the digestive system. The food gets ingested, propelled down to the stomach, and then during the mechanical digestion, it does not make it down to chemical compounds because the reflux of gastric acid during the mechanical digestion, pushes the gastric acid contents from the stomach into the esophagus. The medical treatment choice for GERD is PPI which stands for proton pump inhibitors. Proton pump inhibitors reduce the symptoms and reduce the amount of acid that the stomach produces. 

Works Cited 

Libguides: Bio 140 – human biology I – textbook: Chapter 16 – Digestive System Processes and regulation. Chapter 16 – Digestive System Processes and Regulation – BIO 140 – Human Biology I – Textbook – LibGuides at Hostos Community College Library. (n.d.).,digestion%2C%20absorption%2C%20and%20defecation

.Katz, P. O., Dunbar, K. B., Schnoll-Sussman, F. H., Greer, K. B., Yadlapati, R., & Spechler, S. J. (2022, January 1). ACG clinical guideline for the diagnosis and management of gastroesophageal reflux disease. The American journal of gastroenterology.

Belete, M., Tesfaye, W., Akalu, Y., Adane, A., & Yeshaw, Y. (2023, April 19). Gastroesophageal reflux disease symptoms and associated factors among university students in Amhara Region, Ethiopia, 2021: A cross-sectional study. BMC gastroenterology.

One Comment

  1. Her STEAM Project explains the steps of the digestive system and its function as well. Her project is concise and easy to digest. There are 6 steps to digestion which she explains. One will be where we ingest the food this is where we put the food in the mouth and swallowed it and the saliva helps down on breaking it down. I have learned from her steam project that during ingestion saliva has properties that can break down carbohydrates lipids. The second part is where the food is moving through the digestive tract, and it is propulsion. Swallowing is also involved in moving the food. The third step was where the food will be physically processed, I have learned that in the mechanical process of digestion, the food will get smaller to create and increase the surface area to also help with its mobility. These steps will help the food to be processed much easier in the digestive tract as smaller pieces could be easily breakdown by digestive juice. This will promote faster food absorption. The fifth step is when the food is already broken down and the absorption is happening where the nutrients go into the bloodstream and be distributed all over the body. The sixth step is where the indigestible food remains, and this will turn into feces. Ali Earls also explained about GERD and I have learned that this is a condition where the digestive system has an issue with the reflux of gastric contents. I have learned that GERD’s symptoms are heartburn and regurgitation and it also causes saliva production. I have learned that GERD can be treated by proton pump inhibitors to reduce the symptoms as well as the reduction of the amount of acid that is being produced in the stomach.

    Kay Quintana Torres

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