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The oesophagus, or esophagus in American English, is a fibromuscular tube that connects the back of the throat to the stomach. It is approximately 25cm long in adults and is surrounded at the top and bottom by two muscular rings, known as the upper and lower oesophageal sphincters. The oesophagus is made up of several layers, including the mucosa, muscularis mucosa, submucosa, and muscularis propria. The upper oesophageal sphincter is composed of skeletal muscle, while the lower oesophageal sphincter is composed of smooth muscle. The oesophagus is an important part of the digestive system, aiding in the transport of food from the throat to the stomach.
| Characteristics | Values |
|---|---|
| Length | 18-25 cm |
| Diameter | 1 inch |
| Layers | Mucosa, muscularis mucosa, submucosa, muscularis propria |
| Muscularis mucosa | Two- to three-cells thick |
| Muscularis propria | Inner circular and outer longitudinal muscle layers |
| Upper oesophageal sphincter | Anatomical, striated muscle |
| Lower oesophageal sphincter | Functional, smooth muscle |
| Muscle fibres | Spiral, helical, longitudinal, circular |
| Muscle type | Skeletal, smooth |
| Innervation | Voluntary, involuntary |
| Lymphatic drainage | Divided into thirds |
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What You'll Learn
The oesophagus is a fibromuscular tube
The oesophagus, also spelt esophagus, is a fibromuscular tube that connects the back of the throat to the top of the stomach. It is also colloquially known as the food pipe, food tube, or gullet. The oesophagus is about 25 cm (10 inches) long in adults, although its length can vary between 18 and 25 cm. It travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. Only about one centimetre of the oesophagus lies in the abdominal cavity.
The oesophagus is made up of several layers: mucosa, muscularis mucosa, submucosa, and muscularis propria. The mucosa is a stratified squamous epithelium of around three layers of squamous cells, which contrasts with the single layer of columnar cells in the stomach. The muscularis mucosa is thin, two to three cells thick, and oriented in the longitudinal axis. The muscularis propria, also called the muscularis externa, is the dominant muscle layer. It is organised into inner circular and outer longitudinal muscle layers, each of which is several cells thick. The circular and longitudinal muscle layers are approximately 0.75 mm thick under baseline resting conditions.
The oesophagus is surrounded at the top and bottom by two muscular rings, known as the upper and lower oesophageal sphincters. These sphincters act to close the oesophagus when food is not being swallowed. The upper oesophageal sphincter is an anatomical sphincter composed of skeletal muscle, while the lower oesophageal sphincter is a functional sphincter composed of smooth muscle. The upper oesophageal sphincter is not under voluntary control, and it opens when the swallowing reflex is triggered. The lower oesophageal sphincter relaxes to allow food or drink to enter the stomach.
The oesophagus is unique in that it is made up of both skeletal and smooth muscles. The upper part is entirely skeletal, the middle is a mixture of skeletal and smooth muscle, and the lower part is entirely smooth. The upper oesophageal sphincter is composed of skeletal muscle, while the lower oesophageal sphincter is composed of smooth muscle. The smooth muscle in the oesophagus is innervated by involuntary nerves, while the striated muscle is innervated by voluntary nerves.
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It is made up of skeletal and smooth muscles
The oesophagus is a muscular tube that connects the throat to the stomach. It is part of the digestive system and is responsible for carrying food and liquid to the stomach. The oesophagus is surrounded at the top and bottom by two muscular rings, known as the upper and lower oesophageal sphincters, which close the oesophagus when food is not being swallowed. These sphincters are made up of skeletal and smooth muscles.
The upper oesophageal sphincter is an anatomical sphincter, while the lower oesophageal sphincter is a functional sphincter. The upper sphincter is formed by the lower portion of the inferior pharyngeal constrictor, also known as the cricopharyngeal sphincter, due to its relation to the cricoid cartilage of the larynx. The lower oesophageal sphincter, on the other hand, is not an anatomical structure but acts as a sphincter, separating the oesophagus from the stomach.
The oesophagus is made up of several layers, including the mucosa, muscularis mucosa, submucosa, and muscularis propria. The muscularis mucosa is thin, consisting of two to three layers of cells, while the muscularis propria is the dominant muscle layer, with inner circular and outer longitudinal muscle layers. The longitudinal muscle layer originates from the dorsal, superior, and lateral margins of cricoid cartilage, surrounding the circular muscle completely at the inferior end.
The oesophagus is composed primarily of smooth muscle, with striated muscle predominating in its upper third. The smooth muscle is innervated by involuntary nerves, including sympathetic and parasympathetic nerves, while the striated muscle is innervated by voluntary nerves, or lower motor neurons. The smooth muscle fibres detect stretch from the contents swallowed, signalling the brain to contract and push the contents downward.
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It has two muscular rings, or sphincters
The oesophagus is a fibromuscular tube that connects the back of the throat to the top of the stomach. It is a part of the digestive system and is located in the centre of the chest, in an area called the mediastinum. The oesophagus is surrounded at the top and bottom by two muscular rings, or sphincters, which close the oesophagus when food is not being swallowed. These sphincters are known as the upper oesophageal sphincter (UES) and the lower oesophageal sphincter (LES). The UES is an anatomical sphincter, formed by the lower portion of the inferior pharyngeal constrictor, or the cricopharyngeal sphincter, due to its relation with the cricoid cartilage of the larynx anteriorly. The LES, on the other hand, is a functional sphincter, meaning that it acts as a sphincter but does not have a distinct thickening like other sphincters.
The UES surrounds the upper part of the oesophagus and consists of skeletal muscle, while the LES surrounds the lower part of the oesophagus at the junction between the oesophagus and the stomach. The primary muscle of the UES is the cricopharyngeal part of the inferior pharyngeal constrictor. The LES is also called the cardiac sphincter or cardioesophageal sphincter, named after the adjacent part of the stomach, the cardia. The UES senses when food or liquid is coming towards it and relaxes or opens to let food enter the oesophagus. Once food has entered the oesophagus, waves of muscular contractions (peristalsis) push the food downward. The LES relaxes to allow food or drink to enter the stomach.
Dysfunction of the LES can cause gastroesophageal reflux, which, in turn, can lead to gastroesophageal reflux disease (GERD). With GERD, stomach acid persistently flows back into the oesophagus, causing damage to the oesophageal mucosa. Other problems that can affect the oesophagus include achalasia, where the LES does not open when it is supposed to, preventing food from reaching the stomach; esophageal diverticulum, a pouch that bulges outward in a weak section of the oesophageal lining; and esophageal varices, which are large or swollen veins on the lining of the oesophagus.
Esophageal spasms are another issue that can affect the oesophagus, causing minor to severe symptoms such as difficulty swallowing and chest pain. These spasms are caused by abnormal muscle contractions in the oesophagus, making it harder for food and liquids to reach the stomach.
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The oesophagus is innervated by the oesophageal plexus
The oesophagus, or oesophageal tract, is a fibromuscular tube that connects the pharynx to the stomach. It is approximately 25 cm long in adults and is made up of several layers, including the mucosa, submucosa, and muscularis propria. The muscularis propria is the dominant muscle layer of the oesophagus and is organised into inner circular and outer longitudinal muscle layers.
The oesophageal plexus receives two types of fibres from the sympathetic trunk: sympathetic postganglionic fibres and preganglionic fibres. The cell bodies of the sympathetic postganglionic fibres are located in the sympathetic chain ganglia, while the cell bodies of the preganglionic fibres are found in the intermediolateral cell column of the thoracic spinal cord. The oesophageal plexus also receives afferent fibres, which are primarily concerned with pain sensation and have cell bodies located in the dorsal root ganglion.
The oesophageal plexus plays a crucial role in the functioning of the oesophagus, influencing the relaxation and contraction of its smooth and striated muscles. The upper oesophageal sphincter and upper striated muscle are supplied by fibres originating from the nucleus ambiguus, while the lower oesophageal sphincter and smooth muscle of the lower oesophagus are supplied by fibres from the dorsal motor nucleus.
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It is surrounded by the aorta, trachea, heart and vertebral column
The oesophagus is a muscular tube that connects the pharynx to the stomach. It is part of the digestive system and carries food and liquid from the throat to the stomach. The oesophagus is located in the centre of the chest, in an area called the mediastinum. It is surrounded by the aorta, trachea, heart, and vertebral column.
The oesophagus is positioned behind the trachea and heart, in front of the vertebral column, and passes through the diaphragm before entering the stomach. The trachea and oesophagus travel closely together through the neck, with the vertebral column situated posterior to the oesophagus. The oesophagus is made up of several layers, including muscle layers. The muscle layers include the muscularis mucosa and the muscularis propria. The muscularis mucosa is thin and oriented in the longitudinal axis, while the muscularis propria is the dominant muscle layer and is organised into inner circular and outer longitudinal muscle layers.
The oesophagus is surrounded by several important structures, including the aorta, which is the main artery carrying oxygenated blood from the heart to the rest of the body. The trachea, also known as the windpipe, is another structure close to the oesophagus. It is part of the respiratory system and carries air to and from the lungs. The heart, a muscular organ responsible for pumping blood throughout the body, is also located near the oesophagus. The vertebral column, also known as the spine, provides support and protection for the spinal cord and is positioned behind the oesophagus.
The oesophagus is closely related to these surrounding structures, and its position can affect its function. For example, the right crus of the diaphragm has a "pinch-cock" effect on the oesophagus, forming the lower oesophageal sphincter. This sphincter regulates the passage of food and liquids into the stomach and helps prevent the reflux of gastric acid into the oesophagus. The oesophagus also receives its arterial supply from branches of the thoracic aorta and is innervated by the oesophageal plexus, which includes sympathetic and parasympathetic fibres.
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Frequently asked questions
The oesophagus is a fibromuscular tube that connects the back of the throat to the top of the stomach. It is also known as the food pipe, food tube, or gullet.
The oesophagus is made up of several layers, including mucosa, muscularis mucosa, submucosa, and muscularis propria. The muscularis propria is the dominant muscle layer and is organised into inner circular and outer longitudinal muscle layers. The oesophagus is unique in that it is made up of both skeletal and smooth muscles.
The oesophagus is surrounded by two muscular rings, known as the upper and lower oesophageal sphincters. These sphincters close the oesophagus when food is not being swallowed. During swallowing, sensors within the smooth muscles of the oesophagus detect the stretch of the contents swallowed, causing the muscles to contract and push the contents downward.
