Structure of the Upper Respiratory Tract PDF

Structure of the Upper Respiratory Tract Objectives       Name and identify the components of the upper respiratory tract Describe the anatomy of the nose and nasal cavity Describe the histology of respiratory epithelium and its adaptations to the functions Describe the anatomy of the nasophar...

Structure of the Upper Respiratory Tract Objectives       Name and identify the components of the upper respiratory tract Describe the anatomy of the nose and nasal cavity Describe the histology of respiratory epithelium and its adaptations to the functions Describe the anatomy of the nasopharynx Describe the cartilages and membranes of the larynx Describe the actions, nerve supply and blood supply of the muscles of the larynx 2 Overview and Divisions of the Respiratory System Functional Classification of the Respiratory System Nasal cavity Pharynx Tongue Esophagus  Facilitates the exchange of gases between the air and blood  Conducting portion, lined by respiratory epithelium, include  nasal cavity, portions of pharynx, larynx, trachea, bronchi, bronchioles (up to terminal bronchiole)  Respiratory portion: gas exchange occurs across respiratory membrane, include  respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli 4 Oral cavity Larynx Trachea Bronchus Bronchioles RIGHT LUNG Ma24.1 LEFT LUNG Nose Root     Superior to the hard palate Peripheral organ of smelling or olfaction Includes external nose and nasal cavity Functions:  Respiration Apex  Humidification  Filtration  Elimination of secretions Naris 5 Nasal Cavity I Sagittal section showing lateral wall of left nasal cavity  Frontal sinus Nasal conchae Boundaries:  Roof: Frontal bone, cribriform plate of ethmoid, sphenoid bone  Floor: Hard palate  Medial wall: Nasal septum  Lateral wall: Three bony plates (nasal conchae) Nasal cavity Sphenoid sinus Hard palate Oral cavity Tongue  FHM 24.3 Superior, middle & inferior nasal conchae subdivide nasal cavity, create turbulence in inspired air 6 Bony framework of Nasal cavity Contents of Nasal Cavity  Paranasal sinuses are air-filled spaces lined by mucous membrane  The nasal mucosa is continous with that in the paranasal sinuses  Superior one-third is the olfactory area, includes olfactory receptor cells  Inferior two-thirds is the respiratory area, conditions inspired air 12 Paranasal Sinuses Imaging Paranasal Sinuses A patient with chronic rhinitis complains of frequent headache which gets worse during morning hours. He noted discharging of watery fluid when the head was lowered. What is the diagnosis ? A. B. C. D. E. Brain tumor Otitis media Frontal sinusitis Maxillary sinusitis Pharyngitis Histology of RT  Pseudo stratified Columnar ciliated epithelium Blood Supply and Epistaxis 22 Epistaxis Nasopharynx    Posterior to nasal cavity and superior to soft palate Lined by respiratory epithelium Contains the opening of the pharyngotympanic tubes (Eustachian/ auditory tube)  Ventilates middle ear  Ensures that pressure remains at near normal environmental air pressure  Drains secretions, infection, or debris from the middle ear space 24 Pharyngeal Tonsils   Collection of lymphoid tissue in the nasopharynx Enlargement may result in upper respiratory airway obstruction 25 A sinus infection (sinusitis) or inflammation can cause a toothache — specifically in the upper rear teeth, which are close to the sinuses. Larynx: Overview Gray’s Anatomy for Students Figure 8.205    Larynx is lined a hollow musculoligamentous structure Lies superior to the lower respiratory tract, continuous with the trachea inferiorly Opens superiorly into the pharynx 27 Laryngeal Cartilages  Larynx consists of: Three unpaired and three paired cartilages  Membranes and ligaments  Intrinsic muscles  28 Laryngeal Cartilages I  Thyroid cartilage consists of: Two laminae fused anteriorly at laryngeal prominence (Adam’s apple)  Superior and inferior to laryngeal prominence are notches  Posterior margin of each lamina elongate into superior and inferior horns  Lateral surface of each lamina has a ridge, oblique line 31  Laryngeal Cartilages II  Cricoid cartilage is shaped like a ring, consists of: Posteriorly: Lamina of cricoid cartilage  Anteriorly: Arch of cricoid cartilage   Arytenoid cartilages are pyramidal shaped consists of an apex and a base Anterior angle of base forms the vocal process  Lateral angle of base form the muscular process  32 Extrinsic Ligaments of the Larynx  Thyrohyoid membrane is a fibro-elastic membrane, Thickens anteriorly and laterally  Has an opening on its lateral surface for internal laryngeal nerve and superior laryngeal artery   Cricothyroid ligament  Free edge forms vocal ligament 33 Summary of Laryngeal Cartilages and Ligaments F A A. Hyoid bone B. Thyrohyoid B H C G I J D E membrane C. Thyroid cartilage D. Cricoid cartilage E. Cricothyroid ligament F. Epiglottis G. Arytenoid cartilage H. Quadrangular membrane I. Vestibular ligament (“false vocal cord”) J. Vocal ligament (“true vocal cord”) 34 Laryngeal Cartilages  Larynx consists of: Three unpaired and three paired cartilages  Membranes and ligaments  Intrinsic muscles  35 Cavity of the Larynx 37 Superior View of Cavity of the Larynx  Rima glottidis + vocal folds = glottis (vocal apparatus)  Piriform fossa: Bounded by aryepiglottic fold (medially) and thyrohyoid membrane (laterally)  Facilitates movement of liquid and solid to the oesophagus 38 C A B D A B C D Extrinsic Laryngeal Muscles   Suprahyoid muscles elevate the larynx  Stylohyoid  Mylohyoid  Digastric  Geniohyoid Infrahyoid muscles depress the larynx  Omohyoid  Sternohyoid  Sternothyroid  Thyrohyoid 42 Overview: Intrinsic Laryngeal Muscles  Adductors of the arytenoid cartilages pull them medially  Sphincters close the laryngeal inlet, a powerful reflex for protection of airway during swallowing G C A Lateral view Lateral view without epiglottis and left thyroid lamina E F D D B Posterior view B F B Lateral view with epiglottis and without left thyroid lamina A. B. C. D. E. F. G. Cricothyroid Posterior cricoarytenoid Lateral cricoarytenoid Oblique arytenoids Transverse arytenoids Thyroarytenoid Vocalis 44 Tensors and Relaxers of Vocal Ligaments Adjust the length of the vocal ligaments by tilting the thyroid cartilage  Tensors: Cricothyroid  Relaxers: Thyroarytenoid 45 Abduction of Vocal Ligaments Adjust the size and shape of the gap btw vocal fold for phonation and respiration Posterior cricoarytenoid  Abductors of vocal folds open the rima glottidis: Posterior cricoarytenoid 46 Adduction of Vocal Ligaments Transverse arytenoids Lateral cricoarytenoid  Adductors of vocal folds close the rima glottidis: Lateral cricoarytenoid and transverse arytenoid and oblique arytenoid 47 Sphincters of Laryngeal Inlet  During swallowing, laryngeal inlet is narrowed and closed by  Contraction of oblique arytenoids and lateral cricoarytenoid  Contraction of aryepiglottic part of oblique arytenoid, pulls the epiglottis towards the arytenoid 48 B C A D Blood and Nerve Supply of the Larynx Superior thyroid artery Inferior thyroid artery Superior laryngeal artery Inferior laryngeal artery  Vagus nerve Superior laryngeal nerve Internal laryngeal nerve External laryngeal nerve Recurrent laryngeal nerve  Larynx receives blood supply from superior and inferior laryngeal arteries  Superior laryngeal nerve (branch of vagus nerve) divides into: Recurrent laryngeal nerve: Motor innervation of ALL muscles of the larynx except cricothyroid  Internal laryngeal nerve: Sensory for mucosa above vocal fold  External laryngeal: Motor innervation of cricothyroid 53 Laryngeal Examination https://www.youtube.com/watch?v=BrnW9xSc1Hw References Acland's video atlas of anatomy or youtube video-animations on muscles/structure of larynx Thank you