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The esophagus is a muscular tube that connects the pharynx to the stomach. Like the rest of the digestive tract, it has the same basic tissue layers: mucosa, submucosa, muscularis, and either adventitia or serosa (depending on the region). When you observe these layers under the microscope, you can see features that show the efficiency of the esophagus as a passageway for food. . The mucosa of the esophagus is lined with a thick stratified squamous epithelium. This protective layer is perfect for resisting friction as food moves down. Underneath this layer, the submucosa contains glands that produce mucus, which lubricates the lumen of the esophagus to make the transition of the swallowed food to the stomach smoother. . The amazing thing is how the esophagus actually moves the swallowed food toward the stomach. It does not rely on gravity at all. Instead, it uses a coordinated wave of muscle contractions (peristaltic movements). These waves push the bolus toward the stomach in a perfectly timed sequence. The upper part of the esophagus contains skeletal muscle, which means the first part of swallowing is under voluntary control. As the bolus moves down, the muscle tissue gradually transitions to smooth muscle, which takes over the process of moving food forward without you having to think about it. . In the area where the esophagus meets the stomach, there is a specialized ring of smooth muscle called the lower esophageal sphincter. This sphincter prevents stomach contents from moving backward. But if this sphincter becomes too loose, acidic stomach contents can move upward into the esophagus. This backflow is what causes acid reflux. Since the esophageal lining is not designed to withstand repeated exposure to strong acidity, even a small decrease in sphincter tightness can lead to the typical burning sensations that some people have after meals. . Histology is amazing and the human body is incredible. . For this video, I used a Leica ZOOM 200 stereoscope and an Olympus BX41 microscope at up to 1000x magnification. #microscopy #histology #esophagus #LearnOnTikTokContest #EducatorAward
Adolfo Sánchez-Blanco, Ph.D21,900 views • 11 months ago
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