Chapter The esophagus, trachea and main bronchi
Feb 11, The muscular layers that form the esophagus are closed tightly at both The esophagus passes close to the trachea (breathing tube) and the. The esophagus is a median structure that lies first behind the trachea and then The esophagus transports food and liquid and can be replaced successfully by. Mar 6, Tracheal stenosis: Inflammation in the trachea can lead to scarring and abnormal channel forms to connect the trachea and the esophagus.
At the superior end of the esophagus is the upper esophageal sphincter that keeps the esophagus closed where it meets the pharynx. The upper esophageal sphincter opens only during the process of swallowing to permit food to pass into the esophagus.
At the inferior end of the esophagus, the lower esophageal sphincter opens for the purpose of permitting food to pass from the esophagus into the stomach.
Stomach acid and chyme partially digested food is normally prevented from entering the esophagus, thanks to the lower esophageal sphincter. If this sphincter weakens, however, acidic chyme may return to the esophagus in a condition known as acid reflux. Acid reflux can cause damage to the esophageal lining and result in a burning sensation known as heartburn.
Anatomy of the Throat and Esophagus - Video & Lesson Transcript | socialgamenews.info
If these symptoms occur with enough frequency, they are known as GERD gastroesophageal reflux disease. Like the rest of the gastrointestinal tract, the esophagus is made of four distinct tissue layers. The mucosa layer forms the inner lining of the esophagus and is the only tissue layer that has direct contact with substances passing through the esophagus.
Non-keratinized stratified squamous epithelial tissue makes up the majority of the mucosa layer and provides protection to the esophagus from rough food particles and acid from the nearby stomach.
Mucous glands in the mucosa produce mucus to lubricate the esophagus and help shield the mucosa from stomach acid. In this lesson, you will learn about the process of swallowing and the structures of the throat and the esophagus.
To help understand this stage of digestion, let's visit with Frank. Frank recently finished a long day at work, and his stomach was growling.
Chapter 21: The esophagus, trachea and main bronchi
So, he stopped by the local hot dog stand for a quick bite to eat. Frank's teeth and saliva broke down his first bite of hot dog, and the slippery mass is now ready for deglutition. This is the term used to describe the act or process of swallowing. It will help you remember this term if you note that the root of the word comes from the Latin language and means to 'gulp or swallow.
The pharynx is what you might commonly refer to as your throat. Anatomically, it is described as the passage that leads from the cavities of the nose and the mouth to the rest of the alimentary canal.
So we see that the pharynx is the upper part of the alimentary canal, which we previously learned is the name used to describe the continuous tube that travels through the body and allows for digestion and absorption of nutrients. An interesting point about the pharynx is that it not only carries the foods and drinks that you consume, it also carries air, which passes through on the way to the lungs.
Now, you swallow hundreds of times a day and likely do not give the process much thought.
Anatomy of the Throat and Esophagus
However, there is a well-orchestrated series of events that must happen so that food and drink you swallow doesn't 'go down the wrong tube,' so to speak. So how does swallowing prevent food and drink from passing into the wrong tube?
Well, to explain this, we need to take a closer look at the anatomy of the pharynx. We see that the pharynx has three divisions. The superior division is called the nasopharynx. It's the part of the pharynx that is continuous with the nasal passages and nose. It's easy to remember this division because the word 'naso' means nose.
The next division is the oropharynx. It's the part of the pharynx that lies at the back of the mouth. This division is also easy to remember because the word 'oro' means mouth.
The lower division of the pharynx is called the laryngopharynx. It is the lower part of the pharynx that leads to the rest of the alimentary canal. You can recall this term by remembering that the word 'laryngo' means larynx.
We will describe the larynx shortly.