Logan Steele
The act of swallowing, also known as deglutition, is a complex process that involves the coordination of multiple organ systems, including the musculoskeletal, neuromuscular, and respiratory systems. It requires the precise collaboration of over 20 muscles, including those in the mouth, pharynx, upper oesophageal sphincter, and upper oesophagus, along with control from several cortical areas and swallowing centres in the brain stem. The process can be divided into distinct phases: oral, pharyngeal, and oesophageal, each with specific functions and muscle activations to ensure the safe passage of food or liquid from the mouth to the stomach.
| Characteristics | Values |
|---|---|
| Number of muscles involved | Over 30 |
| Muscle groups involved | 22 |
| Muscle pairs involved | 50 |
| Muscle coordination | Controlled by cortical areas and the swallowing centres in the brain stem |
| Muscle contraction | Coordinated contraction of the muscles in the mouth, pharynx, upper oesophageal sphincter, and upper oesophagus |
| Muscle control | Voluntary and reflex actions |
| Muscle function | Propulsion of the bolus, protection of the airway |
| Individual muscles | Genioglossus, hyoglossus, styloglossus, mylohyoid, masseter, temporalis, lateral and medial pterygoid, pharyngoesophageal, cricopharyngeus |
Explore related products
What You'll Learn
Involved muscles: genioglossus, hyoglossus, styloglossus, mylohyoid, and more
The act of swallowing, also known as deglutition, is a complex process involving the coordination of over 30 muscles and nerves. It is divided into three stages: the oral phase, the pharyngeal phase, and the oesophageal phase.
The oral phase involves the tongue and several muscles in the oral cavity, including the genioglossus, hyoglossus, styloglossus, and mylohyoid. These muscles help the tongue carry out its wide range of movements involved in swallowing and are integral to the oral stage of swallowing. The genioglossus, hyoglossus, and styloglossus are supplied by CN XII, while the mylohyoid muscle receives its innervation via CN V3. The oral phase is further divided into an oral preparatory phase and an oral propulsive phase. During this stage, food is propelled down the palate by the tongue towards the oropharynx.
The pharyngeal phase is the first irreversible step in the swallowing mechanism and is characterised by a rapid phase of muscle contraction. This stage begins when the bolus reaches the palatoglossal arch and involves the pharynx, larynx, and upper oesophageal sphincter. The pharyngeal phase serves two main purposes: directing food into the oesophagus and protecting the airway from aspiration. During this stage, the larynx and vocal folds contract, covering the entry of the trachea to protect the airways.
The oesophageal phase involves the movement of the bolus through the oesophagus and into the stomach. This stage is characterised by peristalsis, or peristaltic contractions, which are involuntary contractions and relaxations of smooth muscle surrounding the digestive tract. The oesophageal phase is under autonomic control of the swallowing centre located in the lower pons and medulla oblongata of the brainstem.
Kissing Muscles: What Are They and Why Do We Have Them?
You may want to see also
Explore related products
Oral phase: Tongue and mouth muscles
The oral phase of swallowing involves the movement of substances from the mouth (oral cavity) to the pharynx. This phase is further divided into two parts: the oral preparatory phase and the oral propulsive phase. During the oral phase, the tongue and mouth muscles work together to prepare and propel the food bolus towards the pharynx.
The tongue plays a crucial role in the oral phase of swallowing. It is supplied by the genioglossus, hyoglossus, and styloglossus muscles, which are controlled by the hypoglossal nerve (CN XII). The tongue helps to seal the oral cavity when consuming liquids, preventing them from escaping anteriorly. With solids, the tongue moves the food to the post-canine dentition, where it is rotated laterally and undergoes mastication. The tongue's movements are coordinated with cyclical jaw movements to process the food.
The hyoid bone, located in the anterior neck, also plays an important role in controlling tongue and jaw movements during swallowing. It acts as a stabiliser for both the jaw and the tongue, allowing for precise coordination of their movements. The mylohyoid muscle is another important muscle involved in the oral phase of swallowing. It receives its innervation from CN V3 and assists in the complex movements required to propel food towards the pharynx.
The oral phase of swallowing is a voluntary action that requires precise coordination with breathing. This coordination is essential to prevent choking or pulmonary aspiration. While the oral phase is under voluntary control, the subsequent pharyngeal and oesophageal phases are reflex actions that involve the contraction of various muscles in the pharynx, upper oesophageal sphincter, and upper oesophagus.
Exploring Cardiac Muscle Triads: Understanding Their Unique Structure
You may want to see also
Explore related products
Pharyngeal phase: Pharynx and oesophageal sphincter muscles
The pharyngeal phase of swallowing is a complex process that involves the coordination of multiple muscles and nerves. It begins when the bolus reaches the palatoglossal arch, marking the first irreversible step in the swallowing mechanism. During this phase, the soft palate is elevated by the tensor palatini and levator palatini muscles, sealing the nasopharynx to prevent pressure escape into the nasal cavity. The pharyngeal phase ensures that three potential exits (upper airway, mouth, and lower airway) are closed while the bolus is rapidly propelled through the fourth exit, the oesophagus.
Stimulation of receptors in the oropharynx triggers impulses that are sent to the deglutition centre, a collection of neurons that control swallowing, in the medulla oblongata. The deglutition centre then sends impulses back to the uvula and soft palate, causing them to move upward and close off the nasopharynx. This closure, along with the constriction of the laryngeal muscles, prevents food from entering the trachea.
The pharyngeal constrictor muscles, including the stylopharyngeus, then contract to move the bolus through the oropharynx and laryngopharynx. The upper oesophageal sphincter (UES), a fibromuscular structure located behind the larynx, relaxes to allow food to enter the oesophagus. The UES is bordered posterolaterally by the pharyngoesophageal muscles and superiorly by the pharynx, with the cricopharyngeus muscle controlling its opening.
The pharyngeal phase ends as the bolus reaches the UES, and the complex neuromuscular actions during this phase are controlled by the medulla oblongata. This phase serves two primary purposes: directing food into the oesophagus and protecting the airway from aspiration.
What is a Pinus? Muscle or Not?
You may want to see also
Explore related products
Esophageal phase: Oesophagus muscles
The oesophagus is a muscular tube that carries food and liquid from the throat to the stomach. The oesophagus muscles are involved in the oesophageal phase of swallowing, which is the third and final phase of the process, following the oral and pharyngeal phases. During the oesophageal phase, the oesophagus muscles contract to push food and liquid downwards towards the stomach.
The oesophageal phase of swallowing begins once food has passed through the upper oesophageal sphincter (UES) and entered the oesophagus. The UES is a ring-shaped muscle at the opening of the oesophagus that senses when food or liquid is approaching. When it receives the signal, the UES relaxes or opens to allow food to enter the oesophagus. The UES remains contracted at rest to prevent air from entering the oesophagus.
The oesophagus is a hollow, muscular tube that connects the throat to the stomach. It is part of the digestive system and is responsible for transporting food and liquid from the throat to the stomach. The oesophagus muscles contract in a peristaltic-like manner to propel food and liquid downwards. Peristalsis refers to the sequential contraction of the circular and longitudinal muscles of the oesophagus, creating waves of muscular contractions that push food and liquid downward.
The proximal striated oesophageal musculature is directly innervated by the nucleus ambiguus of the medulla, which provides a pattern of motor neurons that sequentially activate the muscularis propria of the circular muscle. The distal, smooth musculature of the oesophagus and the lower oesophageal sphincter (LES) receive innervation from the dorsal motor nucleus of the vagus nerve. The vagus nerve carries both stimulating (cholinergic) and inhibitory (noncholinergic, nonadrenergic) information to the oesophageal musculature.
The LES is another ring-shaped muscle located at the opening of the lower oesophagus. Similar to the UES, the LES senses when food or liquid is approaching and relaxes or opens to allow food to pass through to the stomach. When there is no food or liquid present, the LES remains closed to prevent stomach acid and digestive juices from flowing back into the oesophagus. Dysfunction of the LES can lead to conditions such as acid reflux and gastroesophageal reflux disease (GERD).
Thigh Muscle Injection: Targeting the Right Spot
You may want to see also
Explore related products
Dysfunction: Impaired muscle coordination or contraction
Swallowing is a complex process that involves the coordination of multiple organ systems, including the musculoskeletal, neuromuscular, and respiratory systems. It requires the precise coordination and contraction of over thirty muscles, nerves, and the central nervous system.
Impaired muscle coordination or contraction during swallowing can lead to a condition called dysphagia, which is difficulty swallowing. This can make eating and drinking challenging and unpleasant. Dysphagia can be caused by a variety of conditions that affect muscle function, coordination, or nerve function related to swallowing.
One such condition is achalasia, which is characterized by the loss of function in the lower oesophageal sphincter, preventing food from entering the stomach. Cricopharyngeal spasms, esophageal spasms, and muscular dystrophy can also lead to dysphagia due to abnormal contractions or muscle weakness. Myasthenia gravis, an autoimmune disease, can interfere with nerve signals to muscles, making swallowing difficult.
In addition, neurological conditions such as Parkinson's disease, amyotrophic lateral sclerosis (ALS), cerebral palsy, and multiple sclerosis (MS) can contribute to dysphagia by affecting nerve function, muscle coordination, and movement. Developmental delays, hyperthyroidism, hypothyroidism, and eosinophilic oesophagitis can also lead to impaired muscle coordination or contraction during swallowing.
Diagnosing and treating dysphagia involves a thorough physical exam, assessment of symptoms, and consideration of medical history. Treatment options depend on the underlying cause and severity of the condition. They may include medication, lifestyle changes, or medical therapy such as botulinum toxin injections to relieve muscle spasms. In severe cases, feeding tubes may be necessary to ensure adequate nutrition.
Exploring the Epigastrium: Muscle or More?
You may want to see also
Frequently asked questions
Swallowing, or deglutition, is the process of moving food or liquid from the mouth to the stomach via the pharynx and oesophagus.
Swallowing involves a complex and coordinated effort of over 30 muscles and nerves. Some sources state that the process involves approximately 50 pairs of muscles and nerves.
The muscles involved in swallowing include those in the mouth, pharynx, larynx, upper oesophageal sphincter, and upper oesophagus.
Swallowing can be divided into three or four phases: the oral phase, the pharyngeal phase, and the oesophageal phase. The oral phase involves the preparation and propulsion of the bolus, while the pharyngeal phase involves directing the bolus into the oesophagus and protecting the airway. The oesophageal phase involves peristalsis, a wave of muscular contraction that pushes the bolus down the oesophagus.
Yes, swallowing difficulties can be treated with dysphagia rehabilitation to strengthen and improve the coordination of the swallowing muscles. In severe cases, feeding tubes may be necessary to ensure adequate nutrition.
