The Esophagus: The Four Layers Of The Human Body

The digestion process begins when we bite into our food. We chew our food so that we can break it into smaller pieces, which make it simpler for the body to digest. The following four layers create the esophagus: the mucosa, submucosa, muscularis, and tunica adventitia. Collectively, the mucosa and submucosa build elongated folds. During digestion, the esophageal lumen is occupied with the food and liquids we swallow. However, when we are not swallowing, the elongated folds work to close the lumen. There are two sphincters located within the esophagus. The sphincters maintain a circular shape, and act as a door shutting channels when appropriate (William Circus, 2015). I will be focusing on the lower esophageal sphincter (LES) and its relation to gastroesophageal reflux disorder (GERD). The LES is composed of smooth muscle. The LES functions as a valve, relaxing when we swallow food or drinks so contents can pass into the stomach. It is designed to close firmly after swallowing, so that no contents are directed back into the esophagus. Reflux refers to the backflow of …show more content…
Smooth muscle cells lack the striation component that aligns contractile units. The cells are filled with dense bodies that allow binding of contractile units. Actin filaments project from one end of the dense bodies. Suspended in between the actin are the thick myosin filaments. When the smooth muscle is stimulated to contract, the myosin filaments will start inching toward the actin, resulting in the shortening of fibers. Essentially, once the mesh-like structure of the smooth muscle cell is activated, it will pull the cell membrane inward. The highest force output is generated when the actin and myosin overlap because there is room to shorten. If they are pulled a part a great distance and the interaction is lost between actin and myosin, a force can no longer be