Mouth of a frog - Visual Dictionary
The word throat is used for the parts of the neck anterior to the vertebral column, especially the pharynx and the larynx. The pharynx is the part of the digestive. When you swallow, the soft palate and uvula move upward, helping to keep foods and . and mandible, and the relationship between the deciduous and permanent teeth. The pharynx runs from the nostrils to the esophagus and the larynx. Larynx: Larynx, a hollow, tubular structure connected to the top of the Frogs produce their croaking sounds by passing air back and forth over the vocal folds; .
The pharynx is the common channel for deglutition swallowing and respiration, and the food and air pathways cross each other in the pharynx. In the anesthetized patient, the passage of air through the pharynx is facilitated by extension of the neck. The nasopharynx, at least in its anterior part, may be regarded as the posterior portion of the nasal cavity, with which it has a common function as part of the respiratory system. The nasopharynx communicates with the oropharynx through the pharyngeal isthmus, which is bounded by the soft palate, the palatopharyngeal arches, and the posterior wall of the pharynx.
The isthmus is closed by muscular action during swallowing. The choanae are the junction between nasopharynx and the nasal cavity proper. A mass of lymphoid tissue, the naso pharyngeal tonsil is embedded in the mucous membrane of the posterior wall of the nasopharynx. Enlarged naso pharyngeal tonsils are termed "adenoids" and may cause respiratory obstruction.
Higher up, a minute pharyngeal hypophysis resembling the adenohypophysis may be found see fig. Each lateral wall of the nasopharynx has the pharyngeal opening of the auditory tube, located about 1 to 1. The auditory tube can be catheterized through a nostril. The opening is limited on the superior side by a tubal elevation tubal torusfrom which mucosal folds descend to the palate and side wall of the pharynx.
The part of the pharyngeal cavity posterior to the tubal elevation is termed the pharyngeal recess. Nearby lymphoid tissue is referred to as the tubal tonsil. The auditory tube is pharyngotympanic; i. Hence, infections may spread along this route. The tube equalizes the pressure of the external air and that in the tympanic cavity. The auditory tube, about 3 to 4 cm in length, extends posteriorly, laterally, and superiorly.
It consists of 1 a cartilaginous part, the anteromedial two thirds, which is a diverticulum of the pharynx, and 2 an osseous part, the posterolateral third, which is an anteromedial prolongation of the tympanic cavity.
The cartilaginous part lies on the inferior aspect of the skull, in a groove between the greater wing of the sphenoid bone and the petrous part of the temporal bone see fig. The cartilaginous part of the auditory tube remains closed except on swallowing or yawning, when its opening prevents excessive pressure in the middle ear.
The osseous part of the tube is within the petrous part of the temporal bone. The oropharynx extends inferiorward from the soft palate to the superior border of the epiglottis. It communicates anteriorly with the oral cavity by the faucial oropharyngeal isthmus, which is bounded superiorly by the soft palate, laterally by the palatoglossal arches, and inferiorly by the tongue see fig.
This area is characterized by a lymphatic ring composed of the nasopharyngeal, tubal, palatine, and lingual tonsils. The mucous membrane of the epiglottis is reflected onto the base of the tongue and onto the lateral wall of the pharynx.
The space on each side of the median glosso-epiglottic fold is termed the epiglottic vallecula. Each lateral wall of the oropharynx has the diverging palatoglossal and palatopharyngeal arches, which are produced by the similarly named muscles and are often called the anterior and posterior pillars of the fauces, respectively. The triangular recess tonsillar fossa between the two arches lodges the palatine tonsil, which is often referred to as merely "the tonsil" see fig.
A tonsil is a mass of lympoid tissue containing reaction or germinal centers and related to an epithelial surface in the pharynx. The medial surface of the tonsil usually has an intratonsillar cleft commonly but inaccurately called the "supratonsillar fossa" and a number of crypts fig. The lateral surface is covered by a fibrous capsule and is related to fascia, the paratonsillar vein the chief source of hemorrhage after tonsillectomyand pharyngeal musculature.
The tonsil is supplied by the tonsillar branch of the facial artery, and it drains into the facial vein. Involution of the tonsil begins at puberty. The laryngopharynx extends from the superior border of the epiglottis to the inferior border of the cricoid cartilage, where it becomes continuous with the esophagus. Its anterior aspect has the inlet of the larynx and the posterior aspects of the arytenoid and cricoid cartilages. The piriform recess, in which foreign bodies may become lodged, is the part of the cavity of the laryngopharynx situated on each side of the inlet of the larynx see fig.
Muscles The pharynx consists of four coats of muscles, from within outward: The wall of the pharynx is composed mainly of two layers of skeletal muscles. The external, circular layer comprises three constrictors fig. The internal, chiefly longitudinal layer consists of two levators: The constrictors of the pharynx have their fixed points in the anterior larynx, where they are attached to bones or cartilages, whereas they expand posteriorly, overlap one another from inferior to superior, and end in a median tendinous raphe in the posterior midline.
Their overlapping has been compared with that of three flower pots placed one inside another. The inferior constrictor arises from the cricoid and thyroid cartilages. The cricopharyngeal fibers are horizontal in orientation and continuous with the circular fibers of the esophagus. These fibers act as a sphincter and prevent air from entering the esophagus. A pharyngeal diverticulum may form posterior to the larynx through the fibers of the inferior constrictor.
The middle constrictor arises from the hyoid bone, whereas the superior constrictor arises from the mandible and sphenoid bone. The palatopharyngeus muscle arises from the palate, forms the palatopharyngeal fold, and is inserted into the thyroid cartilage and the side of the pharynx. The stylopharyngeus muscle arises from the styloid process, passes between the superior and middle constrictors, and is inserted with the palatopharyngeus. The stylopharyngeus is supplied by the glossopharyngeal nerve, whereas the palatopharyngeus and the constrictor muscles are innervated by the pharyngeal branch of the vagus nerve probably fibers from the accessory nerve through the pharyngeal plexus that is located on the middle constrictor.
The chief action in which the muscles of the pharynx combine is deglutition or swallowinga complicated, neuromuscular act whereby food is transferred from 1 the mouth through 2 the pharynx and 3 the esophagus to the stomach. The pharyngeal stage is the most rapid and most complex phase of deglutition. During swallowing, the nasopharynx and vestibule of the larynx are sealed but the epiglottis adopts a variable position. Food is usually deviated laterally by the epiglottis and ary-epiglottic folds into the piriform recesses of the laryngopharynx, lateral to the larynx.
The pharyngeal ridge is an elevation or bar on the posterior wall of the pharynx inferior to the level of the soft palate; it is produced during swallowing by transverse muscle fibers.
Innervation and blood supply The motor and most of the sensory supply to the pharynx is by way of the pharyngeal plexus, which, situated chiefly on the middle constrictor, is formed by the pharyngeal branches of the vagus and glossopharyngeal nerves and also by sympathetic nerve fibers.
The motor fibers in the plexus are carried by the vagus although they likely represent cranial accessory nerve components and supply all the muscles of the pharynx and soft palate except the stylopharyngeus supplied by cranial nerve IX and tensor veli palatini supplied by cranial nerve V. The sensory fibers in the plexus are from the glossopharyngeal nerve, and they supply the greater portion of all three parts of the pharynx.
The pharynx is supplied by branches of the external carotid ascending pharyngeal and subclavian inferior thyroid arteries. Larynx The larynx is the organ that connects the lower part of the pharynx with the trachea. It serves 1 as a valve to guard the air passages, especially during swallowing, 2 for the maintenance of a patent airway, and 3 for vocalization.
The anterior aspect of the larynx is quite superficial fig.
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Laterally, the larynx is related to the carotid sheath, infrahyoid muscles, sternomastoid muscle, and the thyroid gland. The larynx is elevated particularly by the palatopharyngeus muscle during extension of the head and during deglutition. The larynx can be examined in vivo by means of a mirror indirect laryngoscopy or a fiber optic instrument direct laryngoscopy see figs.
The thyroid, cricoid, and arytenoid cartilages are composed of hyaline cartilage and may undergo calcification, endochondral ossification, or both, thereby becoming visible radiographically. The other cartilages are elastic in type. The thyroid cartilage fig. The laminae produce a median elevation termed the laryngeal prominence "Adam's apple"which is palpable and frequently visible. The posterior border of each lamina is prolonged superiorly and inferiorly as cornua, or horns.
The superior horn is anchored to the tip of the greater horn of the hyoid bone. The inferior horn articulates medially with the cricoid cartilage. The lateral surface of each lamina is crossed by an oblique line for the attachment of muscles. The cricoid cartilage fig. It comprises a posterior plate, called the lamina, and a narrow, anterior part, the arch. The lamina articulates superolaterally with the arytenoid cartilages.
The cricoid cartilage is at the level of the C6 vertebra, and its arch is palpable. The inferior border of the cricoid cartilage marks the end of the pharynx and larynx and hence the commencement of the esophagus and trachea. The arytenoid cartilages fig. Each has a superiorly-positioned apex which supports the corniculate cartilage and a base that comprises its inferior part. The base sends a vocal process anteriorward for attachment to the vocal ligament and a lateral, muscular process for muscular attachments.
The corniculate and inconstant cuneiform cartilages are nodules in the aryepiglottic folds figs. The epiglottic cartilage see fig. The epiglottis is situated posterior to the root of the tongue and the body of the hyoid bone and anterior to the inlet of the larynx.
The inferior end, or stalk, of the leaf-shaped cartilage is anchored to the posterior aspect of the thyroid cartilage. Taste buds are present in the posterior surface of the epiglottis.
The cricothyroid joint, between the lateral aspect of the cricoid cartilage and the inferior horn of the thyroid cartilage, allows mainly rotation of the thyroid cartilage around a horizontal axis through the joints of the two sides. This produces a tipping motion where the anterior part of the thyroid cartilage moves anterior and inferior.
The cricoarytenoid joint, between the superior border of the lamina of the cricoid cartilage and the base of the arytenoid cartilages, allows gliding and rotation of the arytenoid cartilages. Ligaments The thyrohyoid membrane connects the thyroid cartilage with the superior border of the hyoid bone see fig.
The median part is thickened to form a ligament. The membrane is pierced on each side by the internal laryngeal nerve and the superior laryngeal vessels. The cricothyroid ligament see fig. The term conus elasticus fig.
In acute respiratory obstruction, cricothyrotomy, that is, entering the larynx between the arch of the cricoid cartilage and the thyroid cartilage by penetrating the cricothyroid membrane, is preferable to tracheotomy for the non-surgeon. This "vocal cord" is the upper border of the conus elasticus.
The vocal cords are composed of elastic fibers covered tightly by a vocal fold of mucous membrane fig. The vestibular ligament on each side is an indefinite band situated superior to the vocal ligament and covered loosely by the vestibular fold. The epiglottis is attached by ligaments to the hyoid bone, to the posterior aspect of the tongue, to the sides of the pharynx, and to the thyroid cartilage. Inlet The inlet, or aditus, of the larynx is the passageway from the laryngopharynx into the cavity of the larynx.
It is set obliquely, facing largely posteriorward. It is bounded anteriorly by the superior border of the epiglottis, on each side by the aryepiglottic folds, and inferiorly and posteriorly by an interarytenoid fold fig. The inlet is related laterally to the piriform recesses of the laryngopharynx see fig.
The aryepiglottic folds provide lateral food channels that lead along the sides of the epiglottis, through the piriform recesses, and to the esophagus fig. Closure of the inlet protects the respiratory passages against the invasion of food and foreign bodies. This closure is produced by contraction of the aryepiglottic and transverse arytenoid muscles and by the posterior motion of the epiglottis that is produced by the elevation of the larynx.
This elevation raises the base of the epiglottis more than the superior portions, resulting in a posterior tilting of the epiglottis. Cavity The cavity of the larynx is divided into three portions: These regions are defined by the location of horizontal folds - the vestibular and the vocal folds see fig. Each ventricle resembles a canoe laid on its side, and the two ventricles communicate with one another through the median portion of the laryngeal cavity.
Larynx | anatomy | omarcafini.info
A small diverticulum, the saccule, which extends superiorward from the anterior aspect of each ventricle, possesses mixed glands and has been termed the "oil can" of the vocal folds.
The vestibular folds see fig. The vocal folds, or "vocal cords," which contain the vocal ligaments, are musculomembranous shelves that appear inferior and medial to the vestibular folds. They extend from the angle of the thyroid cartilage in the anterior larynx to its posterior attachment on the vocal processes of the arytenoid cartilages. The bulk of each vocal fold is formed by the vocalis muscle, which is a part of the thyro-arytenoid muscle. The vocal folds and processes, together with the interval rima glottidis between them, are collectively termed the glottis.
The rima glottidis is the narrowest part of the laryngeal cavity and can be seen between the more separated vestibular folds during laryngoscopy see fig. Manipulation of the larynx is used to generate a source sound with a particular fundamental frequency, or pitch. This source sound is altered as it travels through the vocal tractconfigured differently based on the position of the tonguelipsmouthand pharynx.
The process of altering a source sound as it passes through the filter of the vocal tract creates the many different vowel and consonant sounds of the world's languages as well as tone, certain realizations of stress and other types of linguistic prosody. The larynx also has a similar function to the lungs in creating pressure differences required for sound production; a constricted larynx can be raised or lowered affecting the volume of the oral cavity as necessary in glottalic consonants.
The vocal folds can be held close together by adducting the arytenoid cartilages so that they vibrate see phonation. The muscles attached to the arytenoid cartilages control the degree of opening. Vocal fold length and tension can be controlled by rocking the thyroid cartilage forward and backward on the cricoid cartilage either directly by contracting the cricothyroids or indirectly by changing the vertical position of the larynxby manipulating the tension of the muscles within the vocal folds, and by moving the arytenoids forward or backward.
This causes the pitch produced during phonation to rise or fall. In most males the vocal folds are longer and with a greater mass than most females' vocal folds, producing a lower pitch.
The vocal apparatus consists of two pairs of mucosal folds. These folds are false vocal folds vestibular folds and true vocal folds folds. The false vocal folds are covered by respiratory epithelium, while the true vocal folds are covered by stratified squamous epithelium. The false vocal folds are not responsible for sound production, but rather for resonance. The exceptions to this are found in Tibetan Chant and Kargyraa, a style of Tuvan throat singing.
Both make use of the false vocal folds to create an undertone. These false vocal folds do not contain muscle, while the true vocal folds do have skeletal muscle. Other[ edit ] Image of endoscopy The most important role of the larynx is its protecting function; the prevention of foreign objects from entering the lungs by coughing and other reflexive actions. A cough is initiated by a deep inhalation through the vocal folds, followed by the elevation of the larynx and the tight adduction closing of the vocal folds.
The forced expiration that follows, assisted by tissue recoil and the muscles of expiration, blows the vocal folds apart, and the high pressure expels the irritating object out of the throat. Throat clearing is less violent than coughing, but is a similar increased respiratory effort countered by the tightening of the laryngeal musculature.
Both coughing and throat clearing are predictable and necessary actions because they clear the respiratory passageway, but both place the vocal folds under significant strain.
This is achieved by a deep inhalation followed by the adduction of the vocal folds. Grunting while lifting heavy objects is the result of some air escaping through the adducted vocal folds ready for phonation. Stimulation of the larynx by aspirated food or liquid produces a strong cough reflex to protect the lungs. In addition, intrinsic laryngeal muscles are spared from some muscle wasting disorders, such as Duchenne muscular dystrophymay facilitate the development of novel strategies for the prevention and treatment of muscle wasting in a variety of clinical scenarios.
ILM have a calcium regulation system profile suggestive of a better ability to handle calcium changes in comparison to other muscles, and this may provide a mechanistic insight for their unique pathophysiological properties  Disorders[ edit ] Endoscopic image of an inflamed human larynx There are several things that can cause a larynx to not function properly. Larynx transplant is a rare procedure. The world's first successful operation took place in at the Cleveland Clinic and the second took place in October at the University of California Davis Medical Center in Sacramento.
It is caused by the common cold or by excessive shouting.Difference Between Glottis and Epiglottis
It is not serious. Chronic laryngitis is caused by smoking, dust, frequent yelling, or prolonged exposure to polluted air. It is much more serious than acute laryngitis.
Presbylarynx is a condition in which age-related atrophy of the soft tissues of the larynx results in weak voice and restricted vocal range and stamina. Bowing of the anterior portion of the vocal folds is found on laryngoscopy. Ulcers may be caused by the prolonged presence of an endotracheal tube.