The Respiratory System PDF

THE RESPIRATORY SYSTEM Dr. Cynthia. Manalili Dept. of Anatomy and Histology USLS-COM Division of the Respiratory System Function: A. Conducting Zone Upper Respiratory tract - nose, pharynx, larynx, tra...

THE RESPIRATORY SYSTEM Dr. Cynthia. Manalili Dept. of Anatomy and Histology USLS-COM Division of the Respiratory System Function: A. Conducting Zone Upper Respiratory tract - nose, pharynx, larynx, trachea, bronchi, nose oropharynx bronchioles, terminal bronchioles nasal cavities nasopharynx B. Respiratory Zone Lower Respiratory tract - respiratory bronchioles, alveolar ducts, larynx bronchi alveolar sacs and alveoli trachea lungs  External Nose Primary respiratory role : - gaseous exchange & ventilation Apex Secondary function : External nares ( nostrils ) - phonation - olfaction Dorsum nasi - mechanical stabilization of the thorax - biochemical functions Alae nasi Skeleton of the external nose * Bony framework - lined by a mucous membrane - nasal bones - frontal processes of maxilla - formed by the frontal, nasal and maxillary - nasal part of frontal bone bones * Cartilaginous framework - septal & lateral cartilages * Openings --- External Nares - major / minor alar nasal cartilages  Internal Nose - is a large cavity in the anterior aspect of the skull that lies inferior to the nasal bone and superior to the mouth - lines with muscles and mucous membrane - the posterior communicates with the pharynx through the internal nares or choanae. Nasal cavity Divided into R & L halves by nasal septum Each half has floor, roof, lateral & medial ( septal ) walls Extends from the nostrils in front to choanae behind walls  Lateral wall Floor - formed by palatine process of maxilla - marked by 3 projections --- superior, middle & inferior nasal concha with its corresponding & horizontal plate of the hard palate meatuses Roof - body of sphenoid, cribriform plate of Medial wall ( nasal septum ) - upper part – vertical plate of ethmoid ethmoid, frontal & nasal bones, & the posterior part formed by the vomer nasal cartilages 3 regions of the nasal cavity * Nasal vestibule * Respiratory region * Chemosensory / olfactory area  Nasal vestibule Respiratory region This region encompass the lateral & medial walls, the nasal roof, floor & conchae. - forms the beginning of NC anteriorly Nasal Conchae - lumen lined with skin; inferior region bearing * Enlarges surface area of NC sebaceous & sweat glands, coarse hairs * Warms, moistens, & cleans the inspired air ( vibrissae ) --- arrests passage of particles * Inspired dust particles are removed from the air in inspired air by the moist, sticky surface of muc. Memb. * Contaminated mucus is moved backward by ciliary action of the columnar ciliated epith. Meatus Meatus - located inferolateral to each concha Middle meatus - receives opening of maxillary sinus via the Supreme nasal meatus hiatus semilunares - passage beneath highest nasal concha - sometimes displaying an opening of post Inferior meatus ethmoidal sinus - contains the opening of nasolacrimal duct Superior meatus - receives opening of post ethmoidal sinus  Chemosensory / Olfactory area * limited to the superior nasal concha * contains sensory terminals of olfactory nerve Functions of the meatuses: Microstructure of the Nasal Lining 1. Increase the surface area in the internal nose Anterior part of NC & vestibule - continuous with skin 2. Prevents dehydration by trapping water droplets - keratinized stratified squamous epith during exhalation Posterior - transition from non-keratinizing stratified squamous epith to pseudostratified ciliated ( respiratory ) epith  Respiratory epithelium Respiratory epithelium * Muscular walls of arterioles are under endocrine Ciliated columnar or cuboidal epith cells & neural control Non-ciliated columnar cells w/ microvilli * local vascular changes, due to vasomotor autonomic innervation alters thickness & contours of mucosal Basal cells surfaces, resulting alterations in rate of inflow through the passageways Respiratory epithelium Respiratory mucosa is continuous w/ : * Fibrous layer is infiltrated w/ lymphocytes forming diffuse lymphoid tissue - nasopharyngeal mucosa thro’ post nasal apertures - conjunctiva thro’ nasolacrimal duct & lacrimal * secretions of nasal mucosa contains bacteriocides canaliculi lysozymes, lactoferrin, & IgA. - mucosae of sphenoidal, ethmoidal, frontal & maxillary sinuses thro’ their respective openings  Arterial supply Arterial supply * Ant & post ethmoidal branches of ophthalmic aa ethmoidal & frontal sinuses ; nasal roof * infraorbital, sup., ant., & post alveolar branches * Sphenopalatine branch of maxillary aa mucosa of conchae, meatuses & septum of maxillary aa mucosa of maxillary sinus * Septal branch of sup labial ramus of facial aa vestibular septum * Pharyngeal branch of maxillary aa anastomose with sphenopalatine aa sphenoidal sinus common site of bleeding from the nose ( epistaxis ) Innervation Venous drainage – sphenopalatine vein - facial vein Nerves of ordinary sensation - ophthalmic vein Olfactory nerves Lymph drainage - submandibular nodes Autonomic nerves - parotid nodes - upper deep cervical nodes - retropharyngeal nodes  Nerves of ordinary sensation 1. Ant ethmoidal br of nasociliary nn Mediate sensations of pain, touch & temp -- ant & upper parts of septum Trigeminal fibers sensitive to noxious chem 2. Infraorbital nn -- nasal vestibule Derived from maxillary nn & nasociliary 3. Ant sup alveolar nn -- part of septum & ant part of lateral wall branch of ophthalmic nn 1. Lat post sup nasal & med post sup nasal nn Olfactory nn nasopalatine nn -- from sensory cells of area olfactoria, passing post inf nasal br of ant palatine nn into cranial cavity via foramina of cribriform --- post 3 quarters of lateral wall, roof, plate floor & septum Autonomic nn 2. Br from nerve to pterygoid canal a. Sympa postganglionic vasomotor fibers to the --- upper & post part of roof & septum nasal blood vessels b. Postganglionic parasympa fibers providing secretomotor supply to nasal glands Paranasal sinuses Frontal Ethmoidal Sphenoidal Maxillary Paranasal sinuses Rudimentary or absent at birth Enlarge during eruption of permanent teeth & after puberty Open into lateral wall of NC via small apertures Found in interior of their respective bones Lined w/ mucoperiosteum & filled w/ air  Paranasal sinuses Function of the sinuses Act as resonators to the voice Add some resonance to the voice When apertures of sinuses are blocked, or become Impt in contouring the head for identification of filled w/ fluid, quality of voice is markedly changed gender, sexual maturity, & group identity Produces mucus Frontal sinus Frontal sinus Contained w/in frontal bone posterior to superciliary arches 3.2 cm x 2.6 cm x 1.8 cm Roughly triangular in shape Well-developed between 7th & 8th years, reach full Extends upward above medial end of eyebrow & size after puberty backward into medial part of roof of orbit More prominent in males Aperture opens into middle meatus via the ethmoidal infundibulum or thro’ the frontonasal duct  vessels & nerve supply Ethmoidal sinus Arterial supply -- supraorbital aa ant ethmoidal aa Lie between upper part of NC & the orbit Venous drainage -- supraorbital vv Separated by the paper thin orbital plate of sup ophthalmic vv ethmoid ( poor barrier to infection ) Lymph drainage -- submandibular nodes Small thin-walled cavities, formed by frontal, Nerve supply ---- supraorbital nerve maxillary, lacrimal, sphenoid & palatine bones Ethmoidal sinus vessels & nerve supply Anterior group ( infundibular sinus ) Arterial supply -- sphenopalatine aa - opens into ethmoidal infundibulum or ant & post ethmoidal aa frontonasal duct Venous drainage - via corresponding veins Middle group ( bullar sinus ) Lymphatics -- submandibular nodes - opens into middle meatus Innervation -- ant & post ethmoidal nerves Posterior group ( sensory ) - opens into sup meatus, highest meatus & orbital branches of pterygo- sphenoidal sinus palatine ganglion ( parasympa secretomotor fibers)  Sphenoidal sinuses vessels & nerves Arterial supply -- post ethmoidal aa Situated post to upper part of NC, w/in the Venous drainage - thro’ its corresponding vein Lymphatics -- retropharyngeal nodes sphenoid bone Nerve supply -- post ethmoidal nn ( sensory ) Each sinus opens into the sphenoethmoidal recess orbital branch of pterygopalatine ganglion above sup concha ( parasympa secretomotor ) Maxillary sinus Maxillary sinus Sinus opens into middle meatus thro’ the hiatus Largest air sinus of the nose semilunares Pyramidal in shape Roots of 1st & 2nd premolars, 3rd molar, & root roof – floor of orbit of canine project up into the sinus floor – alveolar process of maxilla Occasionally, thin layer of compact bone apex - zygomatic process enclosing roots of teeth is absent base - lateral wall of nose * tooth extraction may result in fistula * an infected tooth may produce sinusitis  vessels & nerve supply Clinical anatomy Blood supply - facial, infraorbital Congenital nasal deformities greater palatine aa & vv Traumatic injury Lymph - submandibular nodes Infection Nerve supply - infraorbital Surgical procedures ant, middle, & post sup alveolar nn The Pharynx (Throat) 1. Nasopharynx - lies posterior to the nasal cavity and extends to the soft palate. - receives air from the nasal cavity along with packages of dust-laden mucus. - lined with pseudostratified ciliated columnar epithelium - the cilia move the mucus down towards the inferior portion of the pharynx. - also exchanges small amounts of air with the auditory tubes to equalize air pressure b/w pharynx and middle ear. Pharynx 2. Oropharynx - lies posterior to the oropharynx - has only 1 opening from the mouth called the fauces - has both respiratory and digestive functions, serving as a common passageway for air, food and drink. - subjected to abrasion by food particles - lined with nonkeratinized stratified squamous epithelium. - has 2 pairs of tonsils, the palatine and lingual tonsils. Pharynx 3. Laryngopharynx - opens into the esophagus posteriorly and the larynx (voice box) anteriorly. - has both respiratory and a digestive pathway - lined by nonkeratinized stratified squamous epithelium.  The larynx The larynx A specialized organ that provides a protective In adult males, lies opposite 3rd to 6th CV; higher sphincter at the inlet of air passages in children & adult females Responsible for voice production In males, continues to grow till 40 yrs of age w/ Above, it opens into the laryngopharynx thyroid cartilage projecting in anterior midline of Below, is continuous w/ the trachea the neck skeleton of the larynx Cartilages form the skeletal framework Interconnected by ligaments & fibrous membrane Moved by a number of muscles Lined by mucous membrane  Thyroid cartilage thyroid cartilage Largest of the laryngeal cartilages Line of fusion is 90 degrees in males, 120 2 laminae of hyaline cartilage meeting in the degrees in females midline forming the prominent V angle of the The shallower angle in males is asso w/ the Adam’s apple prominence, greater length of vocal cords & the Laryngeal prominence well marked in men, deeper pitch of voice scarcely visible in women thyroid cartilage Cricoid cartilage Superior cornu Formed from a complete ring of hyaline cartilage Inferior cornu Skeletal foundation of the larynx Oblique line - for attachment of the ff Forms a complete ring around the airway muscles : sternothyroid Articulated by synovial joints to thyroid cartilage thyrohyoid & the 2 arytenoids inf constrictor mm  Arytenoid cartilage Arytenoid cartilage Pyramidal in shape Apex supports the corniculate cartilage Situated @ the back of the larynx, on the lateral Base articulates w/ cricoid cartilage part of upper border of cricoid’s lamina Vocal process – gives attachment to the vocal 3 surfaces, 2 processes, base, & an apex ligament Muscular process – gives attachment to posterior & lateral cricoarytenoid mm Corniculate cartilage Cuneiform cartilage 2 small nodules that articulate w/ apices of 2 small rod-shaped pieces of cartilages arytenoid cartilages Serves as support for the aryepiglottic folds Gives attachment to the aryepiglottic folds  Epiglottic cartilage classification of laryngeal cartilage Elastic fibrocartilage Leaf-shaped elastic cartilage, situated behind the - little tendency to ossify or calcify root of the tongue - corniculate epiglottis Connected in front to body of hyoid bone, & by cuneiform apices of arytenoids its stalk ( petiolus ) to the back of thyroid cartilage tritiate Hyaline cartilage - calcifies as age advances - thyroid greater part of arytenoids cricoid Membranes & ligaments of the Larynx Cavity of the Larynx Extrinsic ligaments thyrohyoid membrane Extends from inlet to lower border of the cricoid median & lateral thyrohyoid ligament carilage cricotracheal ligament Divided into 3 parts, the upper, middle & lower Intrinsic ligaments part fibroelastic membrane of the larynx quadrangular memb cricothyroid ligament  Inlet of the Larynx ( aditus laryngis ) Upper part of LC Bounded in front by upper margin of epiglottis Lateral – aryepiglottic fold of mucous membrane The vestibule of the larynx extends from the inlet Posterior – mucous memb between arytenoid to vestibular folds cartilages Anterior wall – post epiglottic surface Aperture between larynx & pharynx Lateral wall - aryepiglottic folds Posterior wall – arytenoid cartilage Middle part of LC Rima glottidis ( glottis ) Fissure between vocal folds anteriorly & arytenoid cartilage posteriorly Smallest Extends from level of vestibular folds to level of 2 regions : intermembranous part vocal folds intercartilaginous part Narrowest part of the larynx  Rima glottidis ( glottis ) Lower part of LC Ave sagittal diam in adult males = 23 mm Extends from level of vocal folds to lower border females = 17 mm of cricoid cartilage Its width & shape vary w/ movements of vocal Continuous w/ the trachea folds & arytenoid cartilages during respiration & phonation