Physiology and Pathophysiology of Deglutition

Esophagus

One of the major focuses of our research laboratory is towards bettering understanding of physiology and pathophysiology of the normal swallowing process and its disorders. Motility of the esophagus and its associated sphincters, i.e., upper and lower esophageal sphincters is an area of intense investigation in our laboratory for the last 30 years. We have made several seminal physiological and pathophysiological observations that have improved our understanding of this field.

Once swallowed, foods, liquid and solids, moves down from the top end of the gut (mouth) to the lower end of gut (Rectum) automatically or without person having any knowledge or make any effort for it. It happens because of the sophisticated structure and function of the gastrointestinal tract. Science that deals with the above field is called Neuro-gastroenterology and Motility. This complex system involves unique morphology of various structures of gastrointestinal (GI) tract, smooth and skeletal muscles, a unique nervous system of the wall of gut (also called as myenteric plexus or little brain) which is influenced by central or big brain through two sets of autonomic nervous systems (sympathetic and parasympathetic) that connect the little brain to the big brain. Communication between big brain and little brain happens through various chemicals called neurotransmitters. Hormones circulating in the blood and paracrine substances released by unique cells that sit in the vicinity of the myenteric nervous system also play crucial roles in the seamless functioning of the GI motility. It is not hard to imagine what may happen if the system goes haywire; symptoms of difficulty swallowing, difficulty breathing, choking, vomiting, intestinal obstruction, diarrhea, constipation, incontinence of bowel, angina like chest pain and abdominal pain are some of the most common symptoms seen by physicians in their clinical practice. Since the system is extremely complex, researchers and clinicians have tremendous amount to learn. With explosion of technology in so many areas during last 20 years, it is indeed an extremely exciting times for the researchers to be involved in the field and for the clinicians to translate the basic science to clinical practice. Pharmacologic industry is also at the forefront of exploring new agents to treat these conditions and from the surgeon’s point of view it is indeed exciting times to be discovering new surgical procedures, devices and non-invasive operative techniques.

Neurogastroenterology and motility as a research field is in its infancy. Since the system is extremely complex, researchers and clinicians have tremendous amount to learn.