Pharynx: lies exactly behind and the mouth and nasal cavity. * Larynx: called as voice box and its part epiglottis prevent flow of In the human body, what is the relationship between the pharynx, trachea, bronchi, and lungs?. Portions of the pharynx lie posterior to the nasal cavity (nasal pharynx), oral cavity This figure illustrates the relationship between the longitudinal and circular the entrance to the lower respiratory passages (trachea, bronchi, and lungs) and. The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity and above the esophagus and larynx, or the tubes going down to the the nostrils of the nose, the larynx, trachea, bronchi, and bronchioles—filters, .. Special pages · Permanent link · Page information · Wikidata item · Cite this.
The oropharynx is lined by non-keratinised squamous stratified epithelium. The HACEK organisms HaemophilusActinobacillus actinomycetemcomitansCardiobacterium hominisEikenella corrodensKingella are part of the normal oropharyngeal flora, which grow slowly, prefer a carbon dioxide-enriched atmosphere, and share an enhanced capacity to produce endocardial infections, especially in young children. It lies inferior to the epiglottis and extends to the location where this common pathway diverges into the respiratory larynx and digestive esophagus pathways.
At that point, the laryngopharynx is continuous with the esophagus posteriorly. The esophagus conducts food and fluids to the stomach ; air enters the larynx anteriorly.
During swallowing, food has the "right of way", and air passage temporarily stops. Corresponding roughly to the area located between the 4th and 6th cervical vertebraethe superior boundary of the laryngopharynx is at the level of the hyoid bone.
The laryngopharynx includes three major sites: Like the oropharynx above it, the laryngopharynx serves as a passageway for food and air and is lined with a stratified squamous epithelium. It is innervated by the pharyngeal plexus. Note that the hyoid bone is not usually considered as part of the larynx and is included in this figure strictly as an aid to orientation.
Before you consider the muscles associated with the laryngeal apparatus, pay very careful attention to the arrangement of the structural components shown in Figure 4, and realize that three major types of movement are possible: Since the vocal cords are attached to the arytenoid cartilages posteriorly and the thyroid cartilage anteriorly, regulation of vocal cord tension and therefore pitch of the voice is accomplished primarily by pivoting the thyroid cartilage forward or backward at the cricothyroid joint Figure This action is best appreciated by imagining the larynx viewed from above, as is shown semi-schematically in Figure 6.
That the vocal cords on each side are covered with a mucous membrane, so that when they are abducted, relatively little air can pass either between them or around them. The bases of the two arytenoid cartilages are L-shaped. The medial process of each is called the vocal process, and the vocal cords attach to it.
Pharynx - Wikipedia
The lateral process of each is called the muscular process, and most of the muscles which act to abduct or adduct the vocal cords attach to it. Abduction of the vocal cords may be accomplished either by externally rotating the arytenoid cartilages on a pivot located at the angle of the "L" center panel, Figure 6or by sliding the 2 arytenoid cartilages apart slightly right panel, Figure 6.
Realize that there is only 1 muscle which has an abductor action on the vocal cords, although there are several which act to adduct the cords. Figure 7 below indicates with arrows the movements of the epiglottis and arytenoid cartilages which take place during swallowing to block off the entrance to the larynx, to prevent food from entering the larynx.
Basically, the epiglottis is pulled down, and the arytenoid cartilages are pulled forward, toward the epiglottis. Realize that two other mechanisms which are independent of laryngeal movements per se also help to keep food from entering the larynx during swallowing. First, the larynx is raised, along with the pharynx, by the contraction of the longitudinal muscles of the pharynx. Refer to Figure in your atlas, which shows the pharynx opened up to reveal the interior of the pharynx, as seen from behind.
Locate the epiglottis, piriform recesses, and esophagus, and trace the path of a bolus of food from the back of the tongue into the esophagus. On left Side view illustrating the major cartilaginous and ligamentous structural features of the larynx.
Shaded structures are imagined as seen through the thyroid cartilage or hyoid bone. On right Schematic drawing of the larynx as seen from the side to show how movement of the thyroid cartilage at the cricothyroid joint affects the tension of the vocal cords. Schematic drawing of the larynx as seen from above showing the thyroid cartilage, the arytenoid cartilages, and the vocal cords. Schematic drawing of the larynx as seen from the side.
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.
Chapter THE PHARYNX AND LARYNX
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.