Anatomy LC5 Respiratory System PDF University of Northern Philippines 2026

UNIVERSITY OF NORTHERN PHILIPPINES ANATOMY LC5 RESPIRATORY SYSTEM COLLEGE OF MEDICINE, BATCH 2026...

UNIVERSITY OF NORTHERN PHILIPPINES ANATOMY LC5 RESPIRATORY SYSTEM COLLEGE OF MEDICINE, BATCH 2026 Dr. Tagorda | Nov 2022 Transcribers: Achacoso, Acosta, Ammiyao, Anulacion, Avecilla, Busaing Editors: Baltazar, Cabillo, Sadiasa, Abaday COURSE OUTLINE I. INTRODUCTION I. INTRODUCTION A. Anatomical Division THE RESPIRATORY SYSTEM B. Functional Division An organ system that rhythmically takes in air and expels it from the body, II. UPPER RESPIRATORY TRACT thereby supplying the body with oxygen and expelling the carbon dioxide that i. THE NOSE it generates A. External nose Principal organs: nose, sinuses, pharynx, larynx, trachea, bronchi and lungs B. Nasal cavity ii. PARANASAL SINUSES ANATOMICAL 1. Upper Respiratory Tract A. Drainage, Function, Clinical Significance DIVISION The respiratory organs in the HEAD AND NECK B. Maxillary Sinuses Airway from the NOSE through the LARYNX C. Frontal Sinuses D. Sphenoidal Sinuses 2. Lower Respiratory Tract E. Ethmoidal Sinuses The respiratory organs of the THORAX iii. THE PHARYNX Regions from the TRACHEA, BRONCHI, BRONCHIOLES, A. Nasopharynx LUNGS B. Oropharynx FUNCTIONAL 1. Conducting Division C. Laryngopharynx DIVISION Consists of those passages that serve only for airflow D. Sensory Nerve Supply of the Pharyngeal Mucous Membrane E. Blood Supply of the Pharynx Nose → through the major bronchioles (terminal) F. Lymphatic Drainage of the Pharynx G. Pharyngeal Muscles Function during Swallowing 2. Respiratory Division H. Muscles of the Pharynx Consists of the alveoli and other gas- exchange regions of iv. THE LARYNX the distal airway A. Cartilages: Large and Solitary From respiratory bronchioles →alveoli B. Cartilages: Paired and Small Table 1. The Anatomical and Functional Division of the Respiratory System C. Laryngeal Folds: Vestibular and Vocal D. Muscles of the Larynx A. ANATOMICAL DIVISION E. Cavity of the Larynx F. Inlet of the Larynx G. Sphincter of the Larynx H. Mucous membrane of the larynx I. Nerve supply of the larynx J. Blood Supply of the larynx K. Lymph drainage of the larynx III. LOWER RESPIRATORY TRACT i. INTRODUCTION ii. TRACHEA A. Anatomic Characteristics B. Lining Epithelium C. Relation of the Trachea in the Neck D. Nerve Supply, Blood Supply, Lymph Drainage iii. BRONCHI A. Anatomic Characteristics B. Clinical Significance C. Primary, Secondary, Tertiary Bronchi Figure 1. Upper Respiratory Tract and Lower Respiratory Tract iv. BRONCHIOLES A. Anatomic Characteristics of Bronchioles in Comparison to Bronchi B. FUNCTIONAL DIVISION B. Terminal and Respiratory Bronchioles C. Primary, Secondary, Tertiary Bronchi v. AIRWAY AND LUNG ANATOMY vi. LUNGS A. Anatomic Characteristics B. Body of the Lungs C. Root of the Lungs D. Lung Lobes and Fissures E. Bronchopulmonary Segments vii. LUNG COVERING A. Visceral and Parietal Plurae B. Pleural Cuff C. Pleural Space D. Nerve Supply of Pleura E. Clinical Significance viii. REFERENCES Figure 2. Lower Respiratory Tract Page 1 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. II. UPPER RESPIRATORY TRACT i. THE NOSE Consists of the External Nose and Nasal Cavity Both of which are divided by a septum into right and left halves Figure 3. Nasal Cavity A. External nose Figure 5. Nerve Supply of Nose a. Orifices: two elliptical orifices called the nostrils or nares, which are separated from each other by the nasal septum b. Lateral margin: the ala nasi which is rounded and mobile. B. NASAL CAVITY c. Framework of the external nose Begins from the nostrils in front ends to the posterior nasal apertures or - above is formed by: choanae behind, where the nose opens into the nasopharynx o the nasal part of the frontal bone (1) Divided into right and left halves by the nasal septum o nasal bones (2) Each half of the nasal cavity has: o frontal processes of the maxillae (3) ▪ Floor - below is formed by: plates of hyaline cartilage ▪ Roof ▪ lateral wall 1. EXTERNAL NOSE: BLOOD SUPPLY ▪ medial wall Branches of the ophthalmic and the maxillary arteries - supply the skin of the external nose Branches from the facial artery. - Supply skin of the ala and the lower part of the septum Figure 6. Nasal Cavity B.1. NASAL CAVITY: ROOF - Narrow and is formed by: Figure 4. Blood Supply of Nose ▪ Anteriorly: nasal and frontal bones ▪ Middle: cribriform plate of the ethmoid ▪ Posteriorly: downward sloping body of the sphenoid 2. EXTERNAL NOSE: NERVE SUPPLY CN V (Trigeminal): Infratrochlear and external nasal branches of the ophthalmic nerve (CN V1) Infraorbital branch of the maxillary nerve (CN V2) Page 2 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Figure 9. Lateral Wall of Nasal Cavity Inferior Meatus Figure 7. Roof of Nasal Cavity Lies below the inferior turbinate/concha Receives the opening of the nasolacrimal duct B.2. NASAL CAVITY: MEDIAL WALL - Composed of the nasal septum Middle meatus Divides the nasal cavity into right and left halves Lies below the middle concha Upper part of nasal septum: formed by vertical plate of the Contains the: ethmoid and vomer a. Ethmoid Bulla Anterior part: formed by the septal cartilage The septum rarely lies in the midline, thus increasing the size -A rounded swelling /bony projection formed by the middle ethmoidal air of one half of the nasal cavity and decreasing the size of the sinuses, which open on its upper border other nasal cavity- rarely that we have equal sizes of both b. Hiatus semilunaris cavities, because of the position/place of the septum. -A curved opening that lies just below the bulla -The anterior end of the hiatus leads into a funnel-shaped channel called the infundibulum -The infundibulum is continuous with the frontal sinus. Superior meatus Lies below the superior concha Posterior ethmoid sinuses Spheno-ethmoidal Recess Small hollow space above the superior concha Where sphenoid air sinuses open Figure 8. Medial Wall of Nasal Cavity B.3. NASAL CAVITY: LATERAL WALL a. Turbinates/conchae: lateral wall bony projections: o superior nasal concha/turbinate o middle nasal concha/turbinate o inferior nasal concha/turbinate Figure 10. Nasal Cavity Labeled b. Meatus o The space below each concha is called a meatus o Named after the turbinate above it o Superior, middle, inferior meatuses Page 3 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Openings 1. Inferior meatus Nasolacrimal duct 2. Middle meatus Maxillary sinus through hiatus semilunaris Frontal sinuses via infundibulum Anterior group ethmoidal sinuses Middle group ethmoidal sinuses 3. Superior meatus Posterior ethmoidal sinuses 4. Spheno-ethmoidal process Sphenoidal sinuses B.4. NASAL CAVITY: NASAL MUCOSA a. Squamous Mucosa: Vestibule The nasal vestibule is a dilated chamber inside the ala nasi It lined with modified skin and has coarse hairs stiff vibrissae or guard hairs b. Olfactory Mucous Membrane Lines the area above the superior concha Contains nerve endings sensitive to the reception of smell. Figure 12. Nasal Cavity: Nerve Supply c. Respiratory Mucous Membrane Lines the lower part of the nasal cavity b.6. NASAL CAVITY: LYMPH DRAINAGE Function Submandibular nodes: Receives lymph vessels draining the vestibule The presence of warm blood in the venous plexuses serves to heat up the Upper deep cervical nodes: Receives vessels that drain remainder of the nasal inspired air as it enters the respiratory system. cavity The presence of mucus on the surfaces of the conchae traps foreign particles and organisms in the inspired air, which are then swallowed and destroyed by gastric acid. Figure 13. Nerve Drainage Figure 11. Nasal Mucosa B.7. BLOOD SUPPLY TO THE NASAL CAVITY The arterial supply to the nasal cavity is from branches of the maxillary artery, B.5. NASAL CAVITY: NERVE SUPPLY most important: sphenopalatine artery Olfactory Nerve (CN I) - Anastomoses with the septal branch of the superior labial branch of the - The olfactory nerves from the olfactory mucous membrane ascend facial artery in the region of the vestibule. through the cribriform plate of the ethmoid bone to the olfactory Kiesselbach’s Plexus bulbs - A vascular network of the five arteries that supply the nasal septum. Trigeminal Nerve (CN V) nerves of ordinary sensation - The arteries anastomose to form the plexus which is a common site for - Ophthalmic Division (V1) of CN V nosebleeds. - Maxillary Division (V2) of CN V - It lies in the anterior inferior part of the septum known as Little's area, also Kiesselbach's area, or Kiesselbach's triangle Page 4 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Figure 14. Nasal Cavity: Blood Supply ii. PARANASAL SINUSES Figure 16. Paranasal Sinuses. Anterior View and Sagittal View Figure 15. Paranasal Sinuses - cavities found in the interior of the maxilla, frontal, sphenoid, and ethmoid bones Figure 17. Paranasal Sinuses with Fluid - arranged in pairs - are lined with mucoperiosteum and filled with air B. PARANASAL SINUSES: MAXILLARY SINUS - they communicate with the nasal cavity through relatively small apertures Shape: pyramidal, paired called ostia Location: Within body of maxilla behind the skin of the cheek - Only the Frontal and Maxillary sinuses are accessible to clinical examination Boundaries: A.1. DRAINAGE - Roof: formed by the floor of the orbit The mucus produced by the mucous membrane is moved into the nose by - Related to the roots of the premolars and molar teeth ciliary action of the columnar cells. Drainage: opens in the middle meatus of the nose through the Drainage of the mucus is also achieved by the siphon action created during hiatus semilunaris the blowing of the nose. A.2. FUNCTION Act as resonators to the voice; (makes voice loud, clear and deep) Reduce the weight of the skull A.3. CLINICAL SIGNIFICANCE When the apertures of the sinuses are blocked or become filled with fluid, the quality of the voice is markedly changed. Page 5 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. E. PARANAL SINUSES: ETHMOIDAL SINUSES Location: contained within the ethmoid bone, between the nose and the orbit Boundary: separated from the orbit by a thin plate of bone so that infection can readily spread from the sinuses into the orbit. Drainage: - Anterior Ethmoid Sinuses open into the infundibulum - Middle Ethmoid Sinuses opens into the middle meatus, on or above the bulla ethmoidalis - Posterior Ethmoid Sinuses opens into the superior meatus Figure 18. Maxillary Sinus C. PARANASAL SINUSES: FRONTAL SINUSES Shape: Triangular, paired Location: Contained within frontal lobe Boundaries: Separated from each other by a bony septum. - extending upward above the medial end of the eyebrow and backward into the medial part of the roof of the orbit Drainage: Each frontal sinus opens into the middle meatus through the infundibulum Figure 21. Ethmoidal Sinus. Anterior, Middle and Posterior Groups SINUS SITE OF DRAINAGE Maxillary Sinus Middle meatus through hiatus semilunaris Frontal Sinuses Middle meatus via infundibulum Sphenoidal sinuses Sphenoethmoidal recess Ethmoidal sinuses Figure 19. Frontal, Ethmoid, Maxillary and Sphenoid sinuses Anterior Group Infundibulum and into the middle meatus D. PARANASAL SINUSES: SPHENOIDAL SINUSES Location: two sphenoidal sinuses lie within the body of the Middle Group Middle meatus on or above bulla ethmoidalis sphenoid bone Each sinus opens into the sphenoethmoidal recess above the Posterior Group Superior Meatus superior concha. Table 2. Paranasal Sinuses and their site/s of drainage into the nose Figure 20. Sphenoidal Sinus Page 6 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. iii. PHARYNX Figure 23. Nasopharynx B. OROPHARYNX Figure 22. Pharynx This lies behind the oral cavity The floor is formed by the posterior one third of the tongue and the interval between the tongue and epiglottis - funnel shaped Upper end: wider lying under the skull Lower end: narrow becoming continuous with the esophagus opposite the 6th cervical vertebra - situated behind the nasal cavities, the mouth, and the larynx Three Divisions of Pharynx: 1. Nasopharynx- the area behind the nose 2. Oropharynx- the area behind the mouth 3. Laryngopharynx/ Hypopharynx- the area posterior or behind the larynx - Musculomembranous wall of the pharynx A. Deficient anteriorly and replaced by the: 1. Posterior choanae 2. Opening into the mouth 3. The inlet of the larynx Figure 24. Oropharynx o There is no musculomembranous wall of the pharynx anteriorly C. LARYNGOPHARYNX B. Continuous with that of the tympanic cavity by This lies behind the opening into the larynx means of the auditory tube or the Eustachian tube The lateral wall is formed by the thyroid cartilage and the thyrohyoid membrane. DIFFERENT DIVISIONS OF PHARYNX A. NASOPHARYNX Lies above the soft palate and behind the nasal cavities Roof has collection of lymphoid tissue called the pharyngeal tonsil Pharyngeal isthmus: opening in the floor between the soft palate and the posterior pharyngeal wall. Lateral wall: opening of the auditory tube, the elevated ridge of which is called the tubal elevation Figure 25. Laryngopharynx Page 7 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. D. SENSORY NERVE SUPPLY OF THE PHARYNGEAL MUCOUS MEMBRANE F. LYMPHATIC DRAINAGE OF THE PHARYNX Nasopharynx: Trigeminal Nerve Maxillary branch (V2) Directly into the deep cervical lymph nodes Oropharynx: Glossopharyngeal nerve Indirectly via the retropharyngeal or paratracheal nodes into the deep Laryngopharynx: internal laryngeal branch of the Vagus nerve cervical nodes Figure 28. Lymph drainage of Pharynx Figure 26. Nerve supply of Pharynx E. BLOOD SUPPLY OF THE PHARYNX Ascending pharyngeal tonsillar branches of facial arteries Branches of maxillary and lingual arteries Veins of the pharynx form a plexus, which drains superiorly into the pterygoid plexus within the infratemporal fossa, and inferiorly into the facial and internal jugular veins Figure 29. Cadaveric View of the Pharynx G. PHARYNGEAL MUSCLES FUNCTION DURING SWALLOWING During CHEWING: a. Masticated food is formed into a ball or bolus on the dorsum of the tongue b. Voluntarily pushed upward and backward against the undersurface of the hard palate c. Soft palate then squeezes the bolus backward into the pharynx. During mastication, air can enter the oropharynx via the mouth. d. From this point onward, the process of swallowing becomes an involuntary act During SWALLOWING nasopharynx is shut off from the oropharynx: a. Why? Figure 27. Blood supply of Pharynx - To prevent the passage of food and drink into the nasal cavities b. How is it done? - Elevation of soft palate by contraction of Levator Veli Palatini - Pulling forward of the posterior wall of the pharynx by the superior constrictor muscle and palatopharyngeus muscle Page 8 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Figure 30. Phases of Swallowing H. MUSCLES OF THE PHARYNX Muscle Origin Insertion Nerve Action Supply Figure 31. Muscles of the Pharynx Superior Medial Pharyngeal Pharynge Aids soft palate in constrictor pterygoid plate, tubercle of al plexus closing off nasal Pharyngeal Muscles Innervation pterygoid occipital pharynx; propels a. All the muscles of the pharynx are innervated by PHARYNGEAL hamulus, bone, bolus downward PLEXUS except for the Stylopharyngeus (innervated by the pterygomandib raphe in GLOSSOPHARYNGEAL NERVE) ular ligament, midline mylohyoid line posteriorly of mandible iv. LARYNX Middle Lower part of Pharyngeal Pharynge Propels bolus constrictor stylohyoid raphe al plexus downward ligament, lesser and greater cornu of hyoid bone Inferior Lamina of Pharyngeal Pharynge Propels bolus Constrictor thyroid raphe al plexus downward cartilage, cricoid cartilage Cricophary Lowest fibers of Sphincter at lower ngeus inferior end of pharynx constrictor muscles Stylophary Styloid process Posterior Glossoph Elevates larynx ngeus of temporal border of aryngeal during swallowing bone thyroid nerve cartilage Salpingoph Auditory tube Blends with Pharynge Elevates pharynx aryngeus palatophar al plexus Figure 32. The Larynx yngeus LARYNX OVERVIEW: Palatophar Palatine Posterior Pharynge Elevates wall of Cartilages of the Larynx: 3 large solitary, 3 small paired yngeus aponeurrosis border of al plexus pharynx, pulls Laryngeal Folds: Vestibular fold, Vocal fold thyroid palatopharyngeal cartilage arch medially Muscles of the Larynx Table 3. Muscles of the Pharynx a. Movements of the Vocal Folds with Respiration b. Voice Production in the Larynx Cavity of the Larynx Inlet of the Larynx Sphincteric Function of the Larynx Page 9 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. LARYNX GENERALITIES: 1. The larynx is an organ that provides a protective sphincter at the inlet of the air passages and is responsible for voice production. 2. Location: lies at the level of the 4th -6TH cervical vertebrae 3. Relations: a. Superiorly, it is situated below the tongue and hyoid bone b. Between the great blood vessels of the neck 4. Boundaries: a. Above: It opens above into the laryngeal part of the pharynx b. Below it is continuous with the trachea. 5. The larynx is covered in front by the infrahyoid strap muscles and at the sides by the thyroid gland. 6. The framework of the larynx is formed of cartilages that are held together by ligaments and membranes, moved by muscles, and lined by mucous membrane 7. Involved in breathing, producing sound and protecting the trachea against food aspiration. 8. The opening of larynx into pharynx known as the laryngeal inlet is about 4–5 centimeters in diameter. Figure 33a.b. Anterior and Posterior View of the Large and Solitary Cartilages of the A. LARYNX: CARTILAGES (LARGE AND SOLITARY) Larynx B. LARYNX: CARTILAGES (PAIRED AND SMALL) Solitary and EPIGLOTTIC THYROID CRICOID CARTILAGE relatively CARTILAGE CARTILAGE ARYTENOID CORNICULATE CUNEIFORM large Cartilage CARTILAGES CARTILAGES CARTILAGES of the Larynx Shape Pyramid shaped Conical- shaped Rod-shaped Location Most Below Inferior to the Function Apex: articulates with Give attachment Found in the superior epiglottic thyroid cartilage corniculate cartilage to the aryepiglottic one cartilage Base: articulates with aryepiglottic folds folds the lamina of the Above cricoid cricoid cartilage Serve to cartilage Vocal process: strengthen projects forward and aryepiglottic Shape Spoon Largest. Ringlike gives attachment to folds. shaped shieldlike shape the vocal ligament Muscular process: Function Supportive Broadly covers Connects the projects laterally give plate in the the anterior and larynx to the attachment to the epiglottis lateral aspects trachea. posterior and lateral of the larynx. cricoarytenoid muscles Thyroid and Anterior peak of cricoid cartilages the thyroid essentially cartilage called constitute the Table 5. Paired and Small Cartilages of the Larynx the laryngeal “box” of the voice prominence. box Table 4. Large and Solitary Cartilages of the Larynx Figure 34. Posterior View of the Paired and Small Cartilages of the Larynx Page 10 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. VESTIBULAR FOLD VOCAL FOLD (VOCAL CORD) Location Fixed fold on each side of Mobile fold on each the larynx side of the larynx Formed by mucous Formed by mucous membrane covering the membrane covering vestibular ligament the vocal ligament Superior fold Inferior fold Color Vascular Avascular Pink in color White in color Function Play no role in speech. Voice production Close the larynx during swallowing Table 6. Larynx: Vestibular and Vocal Fold 1. Glottis Figure 35. Cuneiform Cartilage a. Narrowest part of the larynx b. Measures about 2.5 cm from front to back in the male adult and less in the Aryepiglottic folds: female. Extend from the lateral borders of the epiglottis to the c. Composed of: vocal cords AND opening between them arytenoid cartilages, hence the name 'aryepiglottic'. d. Boundaries: - front by the vocal folds - posterior: medial surface of the arytenoid cartilages 2. Rima glottis: a cleft or gap between the vocal folds E. MUSCLES OF THE LARYNX Figure 36. Cricoid and Arytenoid Cartilages D. LARYNGEAL FOLDS (VESTIBULAR AND VOCAL) Figure 38. Posterior View of Cricoarytenoids 1. Movement of the Vocal Fold Respiration Depend on the movements of the arytenoid cartilages, which rotate and slide up and down on the sloping shoulder of the superior border of the cricoid cartilage 2. Five muscles that move the Vocal Folds (Cords) a. Posterior cricoarytenoid: abducting the vocal cords b. Lateral cricoarytenoid: adducting the vocal cords c. Transverse arytenoid: approximates the arytenoid cartilages d. Thyroarytenoid: relaxing the vocal cords Figure 37. The Laryngeal Folds e. Cricothyroid muscle: tenses the vocal cords Page 11 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Figure 39. Posterior Cricoarytenoids 2.a Posterior Cricoarytenoid Contraction Action: Abducts the vocal cords by rotating arytenoid cartilage Figure 41. Cricothyroid- Tensing The rima glottidis is opened During quiet inspiration SOUND PRODUCTION OF THE LARYNX o Vocal folds are abducted o Rima glottidis is triangular in shape with the apex in front Produced by Intermittent release of expired air between the adducted vocal folds results in their vibration and in During deep inspiration the production of sound o Vocal cords are maximally abducted, rima glottidis diamond shaped Quality High-pitched sound: when the cords are relatively taut or stretched 2.b Lateral Cricoarytenoid Muscle Lower-pitched sound: produced when the cords are Action: Adducts the vocal cords by rotating arytenoid cartilage slacker/relax 2.c Transverse Arytenoid Muscle Difference in sex In adult males compared to female: Posterior part of the glottis is narrowed when the arytenoid - vocal cords are usually longer and thicker cartilages are drawn together by contraction of the transverse arytenoid muscles. - vibrate more slowly During expiration - produce lower-pitched sounds o Vocal folds are adducted leaving a small gap between them Loudness of Determined by the force of the air passing between 2.d. Thyroarytenoid Muscle Contraction Sound the vocal cords Action: Relaxes vocal cords Sound vs Vocal cords alone produce sound but not intelligible Lower-pitched sounds are produced when the cords are more intelligible speech. slacked/relaxed speech Crude sounds from the larynx are formed into words 2.e. Cricothyroid Muscle Contraction by collective actions of the pharynx, oral cavity, Action: Tenses vocal cords tongue, and lips High-pitched sounds are produced when the cords are relatively Table 7. Sound Production of the Larynx taut or stretched F. CAVITY OF THE LARYNX Figure 42. Three Divisions of Laryngeal Cavity Figure 40. Thyroarytenoids- Slackening Page 12 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. THE AIRWAY ANATOMY A. Extrathoracic (superior) airway: a. Supraglottic b. Glottic c. Infraglottic region B. Intrathoracic (inferior) airway: a. Trachea b. Bronchi c. Bronchioles LARYNGEAL CAVITY Boundaries: extends from the laryngeal inlet to the lower border of the of the cricoid cartilage where it is continuous with the cavity of the trachea Narrow in the region of the vestibular folds (rima vestibule) Narrowest in the region of the vocal cords (rima glottidis) 3 Divisions/ Regions of the Laryngeal Cavity a. Laryngeal vestibule/supraglottic: situated between the inlet and the vestibular fold - is the upper chamber of the laryngeal cavity between the laryngeal inlet and also the vestibular folds, which encloses the vestibular ligaments and associated soft tissues. Fig 44. Oblique Arytenoid and Thyroepiglottic muscle b. Middle region/Laryngeal Ventricle: situated between the vestibular folds above and the vocal folds below. Functions of Laryngeal Inlet - very thin a. Used only during swallowing: laryngeal inlet is narrowed by c. Lower region/Infraglottic: situated between the vocal folds above and the oblique arytenoid muscle and capped by the epiglottis lower border of the cricoid cartilage below b. During the pharyngeal phase: since the larynx is blocked by the -is the foremost inferior chamber of the laryngeal cavity and is between the epiglottis, breathing is temporarily stopped, causing apnea. vocal folds (which encloses the vocal ligaments and related soft tissues) and therefore the inferior opening of the larynx. H. SPHINCTERIC FUNCTION OF THE LARYNX A Sphincter is a circular muscle that normally maintains constriction of a G. INLET OF THE LARYNX natural body passage which relaxes as required by normal physiological Laryngeal inlet is an opening that is wider in front than behind functioning. Boundaries: o Anterior: upper edge of epiglottis (E) Two Sphincters in the Larynx o Lateral: aryepiglottic folds (AEF) a. Sphincter in Laryngeal inlet o Posterior: mucous between arytenoids (A) - used only during swallowing: laryngeal inlet is narrowed by oblique arytenoid muscle and capped by the epiglottis b. Sphincter at the rima glottides - Coughing, sneezing, Valsalva maneuver Figure 43. The Laryngeal Opening Two INTRINSIC MUSCLES of the Larynx that modify the Laryngeal Inlet a. Oblique Arytenoid Muscle Action: Narrows the inlet by bringing the aryepiglottic folds together b. Thyroepiglottic muscle Action: Widens the inlet by pulling the aryepiglottic folds apart Page 13 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Muscle Origin Insertion Nerve Action Supply Muscles Controlling the Laryngeal Inlet Oblique Muscular Apex of Recurrent Narrows the inlet arytenoid process opposite laryngeal by bringing the of arytenoid nerve aryepiglottic folds arytenoid cartilage together cartilage Thyroepiglottic Medial Lateral Recurrent Widens the inlet by surface margin of laryngeal pulling the of epiglottis nerve aryepiglottic folds thyroid and apart cartilage aryepilottic fold Muscles Controlling the Vocal folds (Cords) Cricothyroid Side of Lower External Tenses vocal cords cricoid border and laryngeal Figure 45. Nerve supply of the Larynx cartilage inferior nerve cornu of thyroid K. BLOOD SUPPLY OF THE LARYNX cartilage Upper half of the larynx: The superior laryngeal branch of the superior Thyroarytenoid Inner Arythenoid Recurrent Relaxes vocal cords thyroid artery (vocalis) surface cartilage laryngeal Lower half of the larynx: The inferior laryngeal branch of the inferior thyroid of nerve artery thyroid cartilage Lateral Upper Muscular Recurrent Adducts the vocal cricoarytenoid border of process of laryngeal cords by rotating cricoid arythenoid nerve arythenoid cartilage cartilage cartilage Posterior Back of Muscular Recurrent Abducts the vocal cricoarytenoid cricoid process of laryngeal cords by rotating cartilage arythenoid nerve arythenoid cartilage cartilage Transverse Back and Back and Recurrent Closes posterior arytenoid medial medial laryngeal part of rimaglottis surface surface of nerve by approximating of opposite arythenoid arytenoid arythenoid cartilages cartilage cartilage Table 8. The Details of the Origins, Insertions, Nerve supply, and Action of the Intrinsic Muscles of the Larynx I. MUCOUS MEMBRANE OF THE LARYNX The mucous membrane of the larynx lines the cavity with ciliated columnar epithelium On the vocal cords where the mucous membrane is subject to repeated Figure 46. Blood supply of Larynx trauma during phonation, the mucous membrane is covered with stratified squamous epithelium L. LYMPH DRAINAGE OF THE LARYNX The lymph vessels drain into the deep cervical group of nodes J. NERVE SUPPLY OF THE LARYNX Sensory Nerves a. Above the vocal cords: Superior laryngeal branch of the Vagus b. Below the level of the vocal cords: Recurrent laryngeal nerve Motor Nerves a. ALL the intrinsic muscles of the larynx except the cricothyroid muscle: Recurrent laryngeal nerve b. Cricothyroid muscle: Vagus Nerve (CN X) Page 14 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. II. LOWER RESPIRATORY TRACT i. INTRODUCTION 1. Dimension in Adults Length is about 4 ½ inches (11.25 cm) Respiratory organs of the Thorax Diameter is about 1 inch (2.5 cm) Regions from the TRACHEA, BRONCHI, BRONCHIOLES, AND LUNGS A mobile cartilaginous and membranous tube Fibroelastic tube is kept patent by the presence of U-shaped A. Functions cartilaginous bar (rings) of hyaline cartilage embedded in its wall 1. Conducting Division: Posterior free ends of cartilage are connected by smooth muscle, the trachealis muscle - Consists of those passages that serve only for airflow - Nose → through the major bronchioles (terminal) 2.Respiratory Division - Consists of the alveoli and other gas-exchange regions of the distal airway - From respiratory bronchioles → alveoli Figure 47. The Lower Respiratory Tract Figure 49. Cross section of the Trachea showing the C-shaped Tracheal Cartilage B. LINING EPITHELIUM ii. TRACHEA a. Mucous membrane of the trachea is lined with pseudostratified ciliated columnar epithelium b. Contains many goblet cells and tubular mucous gland A. ANATOMIC CHARACTERISTICS Starts as: A continuation of the larynx at the lower border of the cricoid cartilage at the level of the 6th cervical vertebra, descending in the midline of the neck Ends at: The carina by dividing into the right and left main bronchi at the level of the sternal angle (opposite the disc between the 4th and 5th thoracic vertebrae). During expiration, the bifurcation rises by about one vertebral level, T4 During deep inspiration, may be lowered as far as the 6th thoracic vertebra. Figure 50. Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (780x). C. RELATIONS OF THE TRACHEA IN THE NECK 1. Anteriorly: Skin, fascia, isthmus of the thyroid gland -(in front of the 2nd, 3rd, and 4th tracheal rings) inferior thyroid vein, jugular arch, Thyroidea ima artery (if present). 2. Posteriorly: Right and left recurrent laryngeal nerves and the esophagus at the back 3. Laterally: Lobes of the thyroid gland and the carotid sheath and contents. Figure 48. Trachea Page 15 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Figure 53. Nerve supply of the Trachea iii. BRONCHI Figure 51. Relation of Trachea in the neck A. ANATOMIC CHARACTERISTICS 1. The trachea bifurcates behind the arch of the aorta into the Right and Left D. NERVE SUPPLY, BLOOD SUPPLY, AND LYMPH DRAINAGE OF THE TRACHEA Principal (Primary or Main) bronchi 2. The bronchi divide dichotomously, giving rise to several million terminal bronchioles that terminate in one or more respiratory bronchioles. TRACHEA: NERVE SUPPLY A. The sensory supply is from the vagi and the recurrent 3. Each respiratory bronchiole divides into 2 to 11 alveolar ducts that enter the laryngeal nerves. alveolar sacs. 4. The alveoli arise from the walls of the sacs as diverticula (outpouching). B. Sympathetic nerves supply the trachealis muscle. - Bronchi diameter: >1mm- if the airways or diameter become 1 or less than 1, these airways are bronchioles. TRACHEA: BLOOD SUPPLY -Upper two thirds: supplied by the Inferior thyroid - The primary bronchi would bifurcate into each of the primary arteries and the bronchus, the primary bronchus bifurcate into the secondary - Lower third: supplied by the Bronchial arteries. bronchus and each of the secondary bronchus would bifurcate to -Bronchial artery: origin is thoracic aorta. the tertiary bronchi, each of the tertiary bronchus would bifurcate into bronchioles. TRACHEA: LYMPH -Drains into the Pretracheal and Paratracheal lymph - Bronchioles that are not lined by alveoli are termed as terminal DRAINAGE nodes and the deep cervical nodes bronchioles. - Bronchioles that are lined by alveoli are termed as respiratory bronchioles Table 8. Nerve Supply, Blood Supply, and Lymph Drainage of the Trachea - Respiratory bronchioles divide into alveolar ducts, these alveolar ducts open into a common sac, within the outpouching the sac has diverticular outpouching called alveoli. Figure 52. Blood Supply of the Trachea Figure 54. The Bronchi Page 16 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. C. COMPARISON BETWEEN PRIMARY, SECONDARY, AND TERTIARY BRONCHI Lower Respiratory Tract: BRONCHI BRONCHI Primary Secondary Tertiary Bronchi Primary Right Principal (Main) Left Principal (Main) Bronchi Bronchi Bronchi Bronchus Bronchus Synonym Main Lobar Segmental Number R: 1 R: 3 R: 10 Dimension Wider, shorter, more Narrower, longer, L:1 -Superior L:10 vertical more horizontal -middle -inferior Length 1 in. (2.5 cm) 2 in. (5 cm) L:2 Branches Three (3) Two (2) -Superior a. Before entering the On entering the -inferior hilum of the Right lung, hilum of the left lung, Portion of Left lung Pulmonary Bronchopulmonary gives off: divides into: the lung Right lung lobe segment - Superior lobar - Superior lobar supplied by bronchus bronchus each - Inferior lobar Supporting Rings of the Overlapping Overlapping plates of b. On entering the bronchus structure cartilage plates of the the cartilage hilum, it divides into a: just like the cartilage - Middle lobar bronchus trachea - Inferior lobar bronchus Blood supply Bronchi tree is nourished by the bronchial artery, which Table 9. Anatomic Characteristics of Primary Bronchi arises from the aorta and carries systemic blood. Table 10. The Primary, Secondary, and Tertiary Bronchi B. CLINICAL SIGNIFICANCE OF PRIMARY BRONCHI - Because the right bronchus is the shorter, wider, more vertical and more direct continuation of the trachea, foreign bodies tend to enter the right instead of the left bronchus. - From there on the foreign bodies will usually pass into the middle or lower lobe bronchi. Figure 55. Diameter of Bronchi Figure 55. Diameter of Bronchi Page 17 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. B. TERMINAL AND RESPIRATORY BRONCHIOLES B.1.Terminal Bronchioles - Final branches of the conducting division Function: air conduction Alveoli: Absent Cilia: - Bronchioles have a ciliated cuboidal epithelium - Cilia allows the mucus draining into the terminal bronchioles from the higher passages by driven back by the mucociliary escalator - Preventing congestion of the terminal bronchioles and alveoli Smooth muscle: - Thin, incomplete circular layer of smooth muscle - Well-developed layer of smooth muscle in their walls enabling them to dilate or constrict Smaller division: Each terminal bronchiole gives off two or more smaller respiratory bronchioles. Blood supply: Bronchial artery B.2 Respiratory Bronchioles - It marks the beginning of the respiratory division about 0.5 mm in diameter. Figure 56. Histologic Image of the Respiratory Bronchioles Function: Gas exchange - Gaseous exchange takes place between the air in the alveolar iv. BRONCHIOLES lumen through the alveolar wall into the blood within the surrounding capillaries. The smallest bronchi divide and give rise to bronchioles Alveoli: Present Airways that are 1 mm < 1 mm < 1 mm (mm) Epithelium Ciliated Ciliated simple Ciliated simple pseudostratified cuboidal epithelium. cuboidal Columnar Epithelium. Goblet cells (+) (-) (-) Glands (+) (-) (-) Cartilage (+) (-) (-) Smooth Well-developed Well-developed Walls have scanty muscles layer of smooth layer of smooth smooth muscle muscle in their muscle in their walls walls enabling enabling them to them to dilate or dilate or constrict constrict Figure 57. Bronchioles Elastic (+) (+) (+) fibers Blood Bronchial artery Bronchial artery Pulmonary artery supply Volume >150 mL 2500 mL (mL) Table 11. Comparison of Bronchi and Bronchioles Page 18 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. TERMINAL RESPIRATORY BRONCHIOLES BRONCHIOLES Definition Final branches of conducting Mark the beginning of the division respiratory division About 0.5 mm diameter Function Air conduction Gas exchange Alveoli Absent Define by the presence of alveoli Cilia Ciliated cuboidal epithelium Non-ciliated simple squamous epithelium in alveolar ducts and smaller divisions Well-developed layer of Walls have scanty smooth muscle Smooth smooth muscle in their walls muscles enabling them to dilate or constrict Smaller Each terminal bronchioles Each divide into 2 or 10 divisions gives off two or more smaller elongated alveolar ducts respiratory bronchioles Mucous None None glands or goblet cells Table 11. Comparison of Terminal and Respiratory Bronchioles v. AIRWAY AND LUNG ANATOMY Figure 59. The Lung and Airway Anatomy vi. LUNGS A. ANATOMIC CHARACTERISTICS OF LUNGS - Lung parenchyma consists of airways (bronchi/bronchioles), alveolar duct and alveoli. - During life, the right and left lungs are soft and spongy and very elastic. - If the thoracic cavity were opened, the lungs would immediately shrink to one third or less in volume. - In the child, they are pink, but with age, they become dark and mottled because of the inhalation of dust particles that become trapped in the phagocytes of the lung. - This is especially well seen in city dwellers and coal miners. - The lungs are situated so that one lies on each side of the mediastinum. - They are therefore separated from each other by the heart and great vessels and other structures in the mediastinum. Shape: conical Figure 58. Lower Respiratory Tract Covering: visceral pleura suspended free in its own pleural cavity, being attached to the mediastinum The anatomy of the Respiratory System can be divided into 2 MAJOR PARTS: only by its root Apex: blunt apex, which projects upward into the neck for about 1 in. (2.5 1. Airway Anatomy cm) above the clavicle a. Extrathoracic (superior) airway Base: middle inner third of the clavicle. Concave base that sits on the -Supraglottic, glottic, infraglottic region diaphragm b. Intrathoracic (inferior) airway: Trachea, Bronchi, Bronchioles - Main function: conduction of air to the alveolar space 2. Lung Anatomy a. Includes the lung parenchyma (respiratory bronchioles, alveolar ducts and alveoli) b. Function: mainly involved in the gas exchange at the alveolar level Page 19 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. B. BODY OF THE LUNGS a. Surfaces: 1. Convex costal surface: corresponds to the concave chest wall 2. Concave mediastinal surface: molded to the pericardium and other mediastinal structures are embedded b. Middle part: the middle of this surface is the hilum Hilum: a depression in which the bronchi, vessels, and nerves that form the root enter and leave the lung. c. Anterior border: thin and overlaps the heart; it is here on the left lung that the cardiac notch is found d. Posterior border: thick and lies beside the vertebral column Figure 61. Hilum of Lungs D. LUNG LOBES AND FISSURES - are double folds of pleura that divide the lungs into lobes: 1. Each lung is covered by the VISCERAL PLEURA. 2. VISCERAL PLEURA forms invaginations into both lungs which are called FISSURES 3. FISSURES divide the lungs into LOBES. (a) Figure 62. Fissures of Lungs (b) Figure 60.a.b. Lungs LUNG LOBES AND RIGHT LUNG LEFT LUNG FISSURES C. ROOT OF THE LUNGS Size Slightly larger Smaller - Formed of structures that are entering or leaving the lung. - Surrounded by a tubular sheath of pleura which joins the Fissures OBLIQUE and OBLIQUE mediastinal parietal pleura to the visceral pleura covering the HORIZONTAL FISSURES lungs. - Composed of: o Bronchi Lobes Upper Lobe Upper Lobe o Pulmonary artery and veins Middle Lobe Lower Lobe o Lymph vessels Lower Lobe o Bronchial vessels Table 11. Lobes and Fissures of the Lungs o Nerves Page 20 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Each lobe of the lungs is divided into bronchopulmonary segments: A. RIGHT LUNG Superior Lobe: 3 Middle Lobe: 2 Inferior Lobe: 5 B. LEFT LUNG Superior Lobe: 5 Inferior Lobe: 5 (a) Figure 64. Anterior view of Lobe of the Lungs E. BRONCHOPULMONARY SEGMENTS It is a pyramid shaped, with its apex toward the lung root. It is surrounded by connective tissue It has a SEGMENTAL BRONCHUS, a SEGMENTAL ARTERY OF PULMONARY ARTERY, LYMPH VESSELS, and AUTONOMIC NERVES. The SEGMENTAL VEIN (tributary of pulmonary vein) lies in the connective tissue between adjacent bronchopulmonary segments. The anatomic, functional, and surgical units of the lungs. Because it is a structural unit, a diseased segment can be removed surgically. vii. LUNG COVERING A. VISCERAL AND PARIETAL PLURAEA. (b) A.1 Visceral Plurae Figure 63. (a) (b) Lung Lobes and Fissures A serous membrane that completely covers the outer surfaces of the lungs and extends into the depths of the interlobar fissures. LUNG FISSURES At the hilum, the visceral pleura turns back on itself and forms the parietal pleura. 1. Oblique Fissure (Major) Each lung is divided roughly in half by an oblique fissure A.2. Parietal Plurae This fissure may be approximately by a string that runs from the T3 spinous process obliquely down and around the chest to the 6th rib at the Which adheres to the mediastinum, superior surface of the diaphragm inner midclavicular line. surface of the rib cage 2. Horizontal Fissure (Minor) - Runs horizontally across the costal surface at the level of the 4th costal cartilage to meet the oblique fissure in the midaxillary line near the 5th rib. - The middle lobe is thus a small triangular lobe bounded by the horizontal and oblique fissures. Page 21 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. Figure 65. Pleurae THE PARIETAL PLEURA Figure 66. Parts of Parital Pleurae MEDIASTINAL PLEURA 1. Covers and forms the B. PLEURAL CUFF lateral boundary of the Union of visceral and parietal pleura mediastinum. Surrounds the structures entering and leaving the lung at the hilum of each 2. At the hilum of the lung. lung, it is reflected as a FUNCTIONS: cuff around the vessels a. To allow for movement of the pulmonary vessels and large bronchi during and bronchi and respiration. becomes continuous with the visceral pleura. PULMONARY LIGAMENT 3. It is thus seen that each lung lies free except at - Fold in the pleural cuff allows some space for movement of the pulmonary its hilum, where it is vessels and large bronchi relative to the mediastinum during respiration attached to the blood - Serves to attach the lung to the mediastinum. vessels and bronchi that constitute the lung root. DIAPHRAGMATIC PLEURA 1. Covers the thoracic surface of the diaphragm. COSTAL PLEURA 1. Lines the inner surfaces of the ribs, the costal cartilages, the intercostal spaces, the sides of the vertebral bodies, and back of the sternum. CERVICAL PLEURA 1. Extends up into the neck, lining the undersurface of membrane. 2. It reaches a level 1 to 1.5 inches above the medial third of the clavicle. Figure 67. Pleural Cuff Table 12. Parts of Parietal Pleura Page 22 of 24 [ANATOMY] 1.05 RESPIRATORY SYSTEM – Dr. Ernesto Tagorda Jr. C. PLEURAL SPACE The space between the parietal and visceral pleura is called the PLEURAL CAVITY. NERVE SUPPLY OF THE PLEURA The PLEURAL CAVITY DOES NOT CONTAIN A LUNG The pleural cavity contains nothing but a film of slippery pleural fluid The cavity is only a POTENTIAL SPACE, meaning there is normally no room PARIETAL PLEURA Sensitive to pain, temperature, between the membranes. touch, and pressure. However, under pathological conditions, the space can fill with air or liquid a. Costal pleura: (leading to PNEUMOTHORAX or PLEURAL EFFUSION) segmentally supplied by the INTERCOSTAL NERVE b. Mediastinal pleura: PHRENIC NERVE c. Diaphragmatic pleura: Supplied over the domes by the PHRENIC NERVE Around the periphery by the LOWER SIX INTERCOSTAL NERVES VISCERAL PLEURA - Sensitive to stretch but is insensitive to common sensations such as pain and touch - Receives an autonomic nerve supply from the PULMONARY PLEXUS CLINICAL SIGNIFICANCE 1. Lung tissue and the visceral pleura are devoid of pain sensitive nerve endings, so that pain in the chest is always the result of conditions affecting the surrounding structures. A. In TUBERCULOSIS or PNEUMONIA, for example, pain may never be Figure 68. Pleural Space experienced. B. Once lung disease crosses the visceral pleura and the pleural cavity to 1. During full inspiration, the lungs expand and fill the pleural cavities. INVOLVE THE PARIETAL PLEURA, PAIN BECOMES A PROMINENT 2. During quiet inspiratio