The innermost layer is lined with non-keratinized stratified squamous epithelium. This thick, durable lining is designed to protect the esophagus from the abrasive effects of swallowed food. Unlike the stomach and intestines, it does not typically absorb nutrients.
As the peristaltic wave approaches the end of the esophagus, the LES relaxes. This relaxation is mediated by the vagus nerve and neurochemical transmitters like nitric oxide and vasoactive intestinal peptide. Once the food passes into the stomach, the LES constricts again to maintain a high-pressure barrier against gastric acid. Clinical Significance Gastrointestinal Anatomy and Physiology: The Es...
The esophagus is approximately 25 centimeters long in adults. It is situated posterior to the trachea and heart, passing through the mediastinum of the thorax. It penetrates the diaphragm at an opening called the esophageal hiatus before connecting to the cardias of the stomach. The innermost layer is lined with non-keratinized stratified
This layer is unique because its composition changes along the length of the tube. The superior third consists of skeletal muscle (voluntary), the middle third is a mix of skeletal and smooth muscle, and the inferior third is entirely smooth muscle (involuntary). It is arranged in inner circular and outer longitudinal layers to facilitate peristalsis. As the peristaltic wave approaches the end of
The tongue pushes the bolus of food posteriorly into the oropharynx. This is the only phase under conscious control.
The primary physiological function of the esophagus is deglutition, or swallowing. This is a complex process categorized into three phases: