What is the difference between esophagus and pharynx

At either end of the esophagus are ring-shaped muscles the upper and lower esophageal sphincters , which open and close. The esophageal sphincters normally prevent the contents of the stomach from flowing back into the esophagus or throat. As a person swallows, food moves from the mouth to the throat, also called the pharynx 1.

The upper esophageal sphincter opens 2 so that food can enter the esophagus, where waves of muscular contractions, called peristalsis, propel the food downward 3. The food then passes through the lower esophageal sphincter 4 and moves into the stomach 5. Merck and Co. From developing new therapies that treat and prevent disease to helping people in need, we are committed to improving health and well-being around the world. The Manual was first published in as a service to the community.

When you swallow, the soft palate and uvula move upward, helping to keep foods and liquid from entering the nasal cavity. Unfortunately, it can also contribute to the sound produced by snoring. Two muscular folds extend downward from the soft palate, on either side of the uvula. Toward the front, the palatoglossal arch lies next to the base of the tongue; behind it, the palatopharyngeal arch forms the superior and lateral margins of the fauces. Between these two arches are the palatine tonsils, clusters of lymphoid tissue that protect the pharynx.

The lingual tonsils are located at the base of the tongue. Perhaps you have heard it said that the tongue is the strongest muscle in the body. Those who stake this claim cite its strength proportionate to its size. Although it is difficult to quantify the relative strength of different muscles, it remains indisputable that the tongue is a workhorse, facilitating ingestion, mechanical digestion, chemical digestion lingual lipase , sensation of taste, texture, and temperature of food , swallowing, and vocalization.

The tongue is attached to the mandible, the styloid processes of the temporal bones, and the hyoid bone. The tongue is positioned over the floor of the oral cavity. A medial septum extends the entire length of the tongue, dividing it into symmetrical halves.

Beneath its mucous membrane covering, each half of the tongue is composed of the same number and type of intrinsic and extrinsic skeletal muscles. The intrinsic muscles those within the tongue are the longitudinalis inferior, longitudinalis superior, transversus linguae, and verticalis linguae muscles.

These allow you to change the size and shape of your tongue, as well as to stick it out, if you wish. Having such a flexible tongue facilitates both swallowing and speech.

As you learned in your study of the muscular system, the extrinsic muscles of the tongue are the mylohyoid, hyoglossus, styloglossus, and genioglossus muscles. These muscles originate outside the tongue and insert into connective tissues within the tongue. The mylohyoid is responsible for raising the tongue, the hyoglossus pulls it down and back, the styloglossus pulls it up and back, and the genioglossus pulls it forward.

Working in concert, these muscles perform three important digestive functions in the mouth:. Figure 2. This superior view of the tongue shows the locations and types of lingual papillae.

The top and sides of the tongue are studded with papillae, extensions of lamina propria of the mucosa, which are covered in stratified squamous epithelium. Fungiform papillae, which are mushroom shaped, cover a large area of the tongue; they tend to be larger toward the rear of the tongue and smaller on the tip and sides. In contrast, filiform papillae are long and thin. Fungiform papillae contain taste buds, and filiform papillae have touch receptors that help the tongue move food around in the mouth.

Lingual glands in the lamina propria of the tongue secrete mucus and a watery serous fluid that contains the enzyme lingual lipase , which plays a minor role in breaking down triglycerides but does not begin working until it is activated in the stomach. A fold of mucous membrane on the underside of the tongue, the lingual frenulum , tethers the tongue to the floor of the mouth. Severe ankyloglossia can impair speech and must be corrected with surgery.

Many small salivary glands are housed within the mucous membranes of the mouth and tongue. These minor exocrine glands are constantly secreting saliva, either directly into the oral cavity or indirectly through ducts, even while you sleep. In fact, an average of 1 to 1. Usually just enough saliva is present to moisten the mouth and teeth.

Secretion increases when you eat, because saliva is essential to moisten food and initiate the chemical breakdown of carbohydrates. Small amounts of saliva are also secreted by the labial glands in the lips.

In addition, the buccal glands in the cheeks, palatal glands in the palate, and lingual glands in the tongue help ensure that all areas of the mouth are supplied with adequate saliva. Outside the oral mucosa are three pairs of major salivary glands, which secrete the majority of saliva into ducts that open into the mouth:.

Figure 3. The major salivary glands are located outside the oral mucosa and deliver saliva into the mouth through ducts. Saliva is essentially The remaining 4. Perhaps the most important ingredient in salvia from the perspective of digestion is the enzyme salivary amylase , which initiates the breakdown of carbohydrates.

Food does not spend enough time in the mouth to allow all the carbohydrates to break down, but salivary amylase continues acting until it is inactivated by stomach acids. Bicarbonate and phosphate ions function as chemical buffers, maintaining saliva at a pH between 6. Salivary mucus helps lubricate food, facilitating movement in the mouth, bolus formation, and swallowing.

Saliva contains immunoglobulin A, which prevents microbes from penetrating the epithelium, and lysozyme, which makes saliva antimicrobial. Each of the major salivary glands secretes a unique formulation of saliva according to its cellular makeup. For example, the parotid glands secrete a watery solution that contains salivary amylase. The submandibular glands have cells similar to those of the parotid glands, as well as mucus-secreting cells.

Therefore, saliva secreted by the submandibular glands also contains amylase but in a liquid thickened with mucus. The sublingual glands contain mostly mucous cells, and they secrete the thickest saliva with the least amount of salivary amylase. Infections of the nasal passages and pharynx can attack any salivary gland. The parotid glands are the usual site of infection with the virus that causes mumps paramyxovirus.

Mumps manifests by enlargement and inflammation of the parotid glands, causing a characteristic swelling between the ears and the jaw. Symptoms include fever and throat pain, which can be severe when swallowing acidic substances such as orange juice.

In about one-third of men who are past puberty, mumps also causes testicular inflammation, typically affecting only one testis and rarely resulting in sterility. I loved it. Name required. Email required. Please note: comment moderation is enabled and may delay your comment.

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You agree that we have no liability for any damages. Functions-The first and the most obvious difference is that the trachea is a part of the respiratory system while the esophagus forms part of the digestive system. Since they belong to different systems, they perform separate functions! Structure-The trachea, commonly called a windpipe, is a strong and wide tube that helps in transporting air to the bronchi.

It is the most important part of animals that breathe in through their lungs. Since it supplies the body with oxygen, it is very important for the trachea to remain open at all times. Some allergic reactions may cause an inflammation of the trachea. The epiglottis drops downward to prevent food from entering the larynx and trachea in order to direct the food into the esophagus. Peristaltic movements propel the food from the pharynx into the esophagus.

The esophagus is a collapsible muscular tube that serves as a passageway between the pharynx and stomach.