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Esophagus

life science Maturity 9-11 Next article →

The esophagus is a vital organ in the digestive system of vertebrates. It acts as a muscular tube that carries food from the pharynx to the stomach. In adult humans, this tube is about 25 cm or 10 inches long. It sits in a tight space behind the trachea and the heart. The tube travels through the diaphragm to reach the stomach. This organ is essential because it provides a path for nutrients to enter the body.

Illu esophagus
Illu esophagus

Moving food through the tube happens through a process called peristalsis. This works through waves of muscle contractions that push food downward. The tube has two muscular rings called sphincters that control the flow. The upper sphincter is an anatomical ring made of skeletal muscle. The lower sphincter is a functional ring that helps prevent acid from moving up. When the lower sphincter fails, it can cause gastric reflux. This is when stomach acid moves back up and causes heartburn.

The word esophagus comes from the Ancient Greek words oisophágos. This name comes from parts meaning "I carry" and "I ate." Scientists have studied its structure to understand how it protects itself. The inner lining is made of many layers of flat cells called stratified squamous epithelium. This tough lining protects the tube from the rough edges of food. The stomach has a different type of single-layer lining. Where these two linings meet, you can see a zig-zag line called the z-line.

There are many specific details about where the esophagus sits in the body. It starts near the sixth cervical vertebra in the neck. It passes through the diaphragm at the tenth thoracic vertebra. It ends at the cardia of the stomach at the eleventh thoracic vertebra. The tube has four specific points where it is narrow or constricted. These include the area behind the cricoid cartilage and the area where the aorta crosses. It also narrows where the left main bronchus presses against it.

Mid esophageal mass
Mid esophageal mass

Understanding the esophagus helps us understand how our whole body works together. It relies on many different nerves to function properly. The vagus nerve is very important for starting the waves of peristalsis. Other nerves, like the sympathetic trunk, help control blood vessels and muscle. Doctors can look inside the tube using a tool during an endoscopy. They can also use X-rays with barium sulfate to see how food moves. This helps them find problems like tears or narrow spots in the tube.

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File:Illu esophagus.jpg
Illu esophagus.jpg
File:Mid esophageal mass.jpg
Mid esophageal mass.jpg
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