Essay Sample Content Preview:
Tracking a Bolus of Food
Your Name
Your Institution of Affiliation
April 29, 2018
Introduction
While a sufficient amount of food is needed to keep the body nourished and functioning, the quantity of food is just one of factors that should be kept in check. In fact, ingestion and digestion of food is a complicated process that involves different mechanism and organ structures to optimally extract the nutrients from the food so the body could use it. To put it into perspective, for a healthy adult, it is stated that this whole process (including excretion) usually takes 24-72 hours from the time when the food enters a person’s mouth to the time when it comes out of the anus (Nelson, n.d.). In light of the importance and the complexity of the digestion process, the author of this article believes that knowing the specifics of the process is critical, especially for practitioners of health. Without a firm knowledge of how we humans extract the resources that keeps them alive, preventing and diagnosing possible health problems would be harder. Thus, in this article, a thorough discussion of the four processes (1) ingestion, (2) digestion, (3) breakdown, and (4) excretion would be detailed.
Ingestion
Even before the food enters the mouth, an individual’s senses are already being stimulated to alert the system and recognize the presence of food. Some of the senses that function to do this are our sense of sight, smell, and sound (ScienceLearn.org, 2014). Together, these senses work to make the food more sumptuous or repugnant based on whether it would be beneficial or dangerous for our body. On the one hand, this is the reason why when individuals are about to ingest materials and substances which are unnecessary, the natural reaction of the body is to puke to expel them. On the other hand, this collaboration between the senses is another reason why the sight and smell of food prompt our body to release more gastric juices. Even according to studies, our ability to taste food is about 80% to 90% reliant on the sense of smell, as compared to the sense of taste (Spence, 2015). Nonetheless, in cases where food is ingested rather than any harmful substances, its journey of becoming broken down and consumed is about to start.
Beginning in the mouth, the food is chewed and broken down into smaller pieces through a process called ‘mechanical digestion.’ The reason why this process is called mechanical is that its main purpose is to make passage easier through the esophagus as well as increase its surface area to improve the ability of the enzymes to break it down using a process called ‘chemical digestion.’ Specifically, the reason why the mixing of the saliva with the food initiates the digestion of both starch and carbohydrates as well as creates a ‘bolus’ of food that is lubricated by mucin (ScienceLearn.org, 2014).
As the food forms into a bolus and descends the digestive tract, a series of unidirectional and rhythmic waves, known as peristalsis, happens in walls of the esophagus to push it down to the underlying sphincters which are near the pharynx (Goyal & Mashimo, 2006). The duration of this movement depends on the size of the bolus, with small ones about 1-3 seconds and the larger ones about 5-8 seconds before hitting the LES or the Lower Esophageal Sphincter.
Breakdown and Digestion
While chemical breakdown happens as early as the food hits the mouth, most of the digestion occurs as it enters the stomach. Within this J-Shaped stru...