Esophagus facts for kids

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Quick facts for kids Esophagus

The digestive tract, with the esophagus marked in red
Latin	oesophagus
System	Digestive system
Artery	Esophageal arteries
Vein	Esophageal veins
Nerve	Sympathetic trunk, vagus
Precursor	Foregut

The esophagus (pronounced ee-SOF-uh-gus) is a very important organ in your body. It's like a muscular tube that helps move the food you eat from your throat down to your stomach. This movement happens thanks to special muscle waves called peristaltic contractions.

In adults, the esophagus is about 25 centimeters (10 inches) long. It runs behind your trachea (windpipe) and your heart. It then passes through a large muscle called the diaphragm before connecting to the top part of your stomach. When you swallow, a small flap called the epiglottis closes over your windpipe. This stops food from accidentally going into your larynx (voice box) and lungs. The word esophagus comes from ancient Greek words meaning "I carry" and "I ate."

The wall of the esophagus has different layers, including muscle fibers. These muscles help push food along. It also has two special muscular rings, called sphincters, one at the top and one at the bottom. The lower sphincter is especially important because it helps prevent stomach acid from flowing back up into the esophagus.

Sometimes, the esophagus can have problems. These can include stomach acid reflux, changes in its lining, or issues with how its muscles move. These problems might make it hard or painful to swallow. Doctors can use special X-rays or a small camera (called an endoscopy) to look inside the esophagus and find out what's wrong.

How Your Esophagus Is Built

The esophagus is a key part of your digestive system. It starts at the back of your mouth and goes down through your chest, through the diaphragm, and into your stomach. It's about 25 centimeters (10 inches) long.

Your esophagus has a good supply of blood vessels that bring it nutrients and take away waste. It also has nerves that help control its movements.

Where the Esophagus Is Located

The esophagus is positioned carefully within your body. In your upper chest, it sits behind your windpipe and in front of your spine. As it goes lower, it passes behind your heart and curves in front of a large blood vessel called the thoracic aorta.

The esophagus (yellow) passes behind the trachea and the heart.

Diagram of thorax showing the esophagus and surrounding structures.

This diagram shows the esophagus in the neck and chest, seen from behind.

Narrow Spots in the Esophagus

Your esophagus has four natural narrow spots. If you accidentally swallow something that's too big or a harmful substance, it's most likely to get stuck or cause damage at one of these points. These constrictions are:

At the very top, where your throat joins the esophagus.
Where a large blood vessel called the aortic arch crosses in front of it.
Where the left main bronchus (a tube going to your lung) presses against it.
Where it passes through the diaphragm muscle.

The esophagus has four narrow points along its path.

Esophageal Sphincters

At the top and bottom of your esophagus are two muscular rings called sphincters. Think of them like one-way valves. They close the esophagus when you're not swallowing food.

The upper esophageal sphincter is at the top. It's made of skeletal muscle but you can't control it directly. It opens automatically when you start to swallow.
The lower esophageal sphincter is at the bottom, where the esophagus meets the stomach. It's also called the cardiac sphincter. This sphincter is very important for keeping stomach acid from flowing back up into the esophagus. If it doesn't work well, it can cause heartburn and a condition called gastroesophageal reflux disease (GERD).

Nerves Controlling the Esophagus

The esophagus is controlled by nerves, mainly the vagus nerve. This nerve helps the muscles of the esophagus contract in waves, which is how food is pushed down. This process is called peristalsis. Other nerves also help, for example, by adjusting blood flow or making the sphincters contract.

Where Esophagus Meets Stomach

The place where the esophagus connects to the stomach is called the gastroesophageal junction. You can often see a zig-zag line there, called the z-line. This line shows where the lining of the esophagus (which is usually pink) changes to the lining of the stomach (which is a deeper red).

Inside the Esophagus Wall

The wall of your esophagus has several layers. The inner lining, called the mucous membrane, is tough and protects against the food you swallow.

The muscle layer of the esophagus is special because it has two types of muscle:

The upper part has striated muscle, which you can find in muscles you control, like your arm muscles.
The lower part has smooth muscle, which works automatically, like the muscles in your stomach.
The middle part has a mix of both.

These muscles are arranged in two layers, one running lengthwise and one circling the tube. This helps them create the squeezing motion of peristalsis.

Glands in the Esophagus

Tiny glands in the esophagus produce mucus. This mucus helps to lubricate the inside of the tube, making it easier for food to slide down and protecting the lining.

How the Esophagus Develops

The esophagus starts to form very early when a baby is developing inside its mother. It grows from a simple tube, gradually becoming the muscular organ we have as adults.

What the Esophagus Does

Swallowing Food

When you eat, food goes from your mouth to your pharynx (throat), and then into your esophagus. The esophagus is the first part of your digestive tract that food enters after leaving your throat.

Here's how it works:

You chew food and swallow it.
The epiglottis closes over your windpipe to prevent choking.
The upper esophageal sphincter relaxes, letting the food enter the esophagus.
The muscles of the esophagus create wave-like contractions (peristalsis) that push the food down.
The lower esophageal sphincter relaxes, allowing the food to enter your stomach.

Stopping Stomach Acid Reflux

Your stomach makes strong gastric acid to help digest food. The lower esophageal sphincter acts like a gate. It closes tightly to prevent this acid from flowing back up into your esophagus. This backflow is called reflux, and it can cause heartburn and damage the delicate lining of the esophagus.

Common Esophagus Problems

Here are some of the main issues that can affect the esophagus:

Inflammation (Esophagitis)

When the esophagus becomes inflamed, it's called esophagitis. This can happen for several reasons:

Stomach acid reflux is a common cause.
Infections, like from a type of yeast called Candida albicans, especially if someone's immune system is weak.
Swallowing certain medications or harmful substances.
Food allergies can also play a role in some types of esophagitis.

Esophagitis can make swallowing painful. Doctors usually treat it by addressing the cause, like managing reflux or treating an infection.

Barrett's Esophagus

If someone has stomach acid reflux for a long time, the lining of the lower esophagus can change. This condition is called Barrett's esophagus. The normal lining is replaced by a different type of cell, similar to those found in the stomach. This change is important because it can increase the risk of developing esophageal cancer.

Esophageal Cancer

Esophageal cancer is a serious disease where abnormal cells grow in the lining of the esophagus. There are two main types. In its early stages, people might not have any symptoms. As it grows, it can make it very hard to swallow solid foods and cause weight loss.

Doctors use different methods to treat esophageal cancer, including radiotherapy (using radiation), chemotherapy (using medicines), and sometimes surgery to remove part of the esophagus. They might also use a stent (a small tube) to keep the esophagus open so a person can eat and drink.

Esophageal Varices

Esophageal varices are swollen, twisted blood vessels in the lower part of the esophagus. They can develop if there are problems with blood flow in the liver, often due to liver disease. These varices usually don't cause problems until they rupture and bleed. A bleeding varix is a serious medical emergency. Doctors can treat bleeding varices by placing a band around the vessel or injecting medicine to help it clot.

Motility Disorders

Motility disorders affect how the muscles of the esophagus move food. This can lead to:

Dysphagia: Difficulty swallowing.
Odynophagia: Painful swallowing.

One example is achalasia, where the lower esophageal sphincter doesn't relax properly, making it hard for food to enter the stomach. Another is a nutcracker esophagus, which can cause very painful swallowing.

Malformations

Sometimes, the esophagus can have problems with its shape or structure:

Esophageal strictures are narrowings in the esophagus, often caused by long-term reflux.
Esophageal atresia is a condition present at birth where the esophagus ends in a closed pouch instead of connecting to the stomach.
Tracheoesophageal fistula is another birth condition where there's an abnormal connection between the esophagus and the windpipe. These two conditions often happen together and are found in about 1 in 3500 births.

Checking the Esophagus with Imaging

Doctors use several ways to look at the esophagus:

X-rays: You drink a special liquid containing barium sulfate, which shows up on X-rays. This helps doctors see the shape of your esophagus and if there are any blockages.
Endoscopy: A doctor inserts a thin, flexible tube with a camera on the end into your esophagus. This allows them to see the lining directly. During an endoscopy, they can also take a small tissue sample (a biopsy) if needed.
CT scans: These are detailed X-ray images that can show if there are any masses or other issues around the esophagus.

A Look Back in History

The word esophagus has been used in medical writings for a very long time. Ancient Greek doctors like Hippocrates wrote about it. The Roman naturalist Pliny the Elder also described its role in animals. The wave-like muscle movements, called peristalsis, were noted by Galen many centuries ago.

The first attempts at surgery on the esophagus were done on dogs in 1871 by Theodore Billroth. Later, in 1877, Vincenz Czerny performed similar surgeries on people. By the early 1900s, doctors were able to remove parts of the esophagus, especially for esophageal cancer.

In 1955, Rudolph Nissen developed a surgery called the Nissen fundoplication. This operation helps control stomach acid reflux by wrapping part of the stomach around the lower esophageal sphincter.

The Esophagus in Other Animals

Vertebrates

In many animals, the esophagus works similarly to humans.

In some birds, the esophagus has a special pouch called a crop to store food before it goes to the stomach.
Ruminants, like cows, have four-chambered stomachs. Their esophagus has a groove that helps milk go directly to a later stomach chamber in young animals.
Horses have a very strong lower esophageal sphincter. This is why horses usually cannot vomit.
The esophagus of snakes can stretch a lot to swallow large prey.
In most fish, the esophagus is very short because their throat is long due to their gills.

The type of muscle in the esophagus can vary among animals. For example, in dogs and ruminants, the entire esophagus is made of striated muscle. This allows them to regurgitate food, which is useful for feeding their young or chewing cud.

It's a common myth that a human could fit through a whale's esophagus. In reality, even in large baleen whales, the esophagus is usually less than 25 centimeters (10 inches) wide when fully stretched.

Invertebrates

Many invertebrates, like molluscs (snails and slugs) and arthropods, also have a tube called an esophagus. It connects their mouth to their stomach. For example, in gastropods (snails and slugs), the esophagus usually wraps around the stomach due to how their bodies develop. In cephalopods (like octopuses), the brain often surrounds the esophagus.