Respiratory Anatomy

THE RESPIRATORY SYSTEM All cells utilize O2 and give off CO2Functions of the Respiratory System: Primarily, to supply O2 and dispose of CO2 Vocalization OlfactionC6H12O6 + 6O2 -> ATP + 6CO2 + 6H2O

  1. What is the primary function of the respiratory system?: To supply O2 and dispose of CO2

  2. What are some additional functions of the respiratory system besides gas exchange?: Vocalization and olfaction

  3. What is the chemical equation representing cellular respiration?: C6H12O6 + 6O2 -> ATP + 6CO2 + 6H2O

RESPIRATION 4 Separate ProcessesPulmonary Ventilation (Breathing): inspiration and expiration Air moving in and out of the lungsExternal Respiration O2 diffuses from the lungs into the blood CO2 diffuses from the blood into the lungsTransportation of Respiratory Gases Completed by the cardiovascular system – blood is the vehicleInternal Respiration O2 diffuses from the blood into the tissue cells CO2 diffuses from the tissue cells into the blood

  1. What is the process of air moving in and out of the lungs called?: Pulmonary Ventilation (Breathing)

  2. Where does O2 & CO2 diffuse from the lungs into?: Blood

  3. What system completes the transportation of respiratory gases?: Cardiovascular system


    FUNCTIONAL ANATOMY Major Organs Nose, nasal cavity, and paranasal sinuses Pharynx Larynx Trachea Bronchi + Branches Lungs + AlveoliUpper Respiratory System = Nose -> LarynxLower Respiratory System = Larynx -> AlveoliNot formally included, but essential: diaphragm andintercostal muscles

THE UPPER RESPIRATORY SYSTEMThe URS is part of the “conducting zone”§ Fairly-rigid conduits down to the microscopicsites of gas exchange§ Functions to warm, humidify, and filter air

  1. What is the Upper Respiratory System (URS) considered a part of?: "Conducting zone".

  2. What are the functions of the Upper Respiratory System?: Warm, humidify, and filter air.

THE NOSE Functions of the Nose Provides an airway Moistens and warms entering air Filters/cleans entering air Serves as a resonating chamber for speech Houses olfactory receptorsTwo Regions1- External Nose and 2 -Nasal Cavity External nose is created by the nasal, frontal, and maxillary bones + hyaline cartilage Nasal cavity is within and posterior to the external nose – divided by nasal septum Roof formed by the ethmoid and sphenoid bones; floor formed by hard and soft palates

  1. What are the functions of the nose?: Provides an airway, moistens and warms entering air, filters/cleans entering air, serves as a resonating chamber for speech, houses olfactory receptors

  2. What are the two regions of the nose?: External Nose and Nasal Cavity

  3. What bones and cartilage create the external nose?: Nasal, frontal, and maxillary bones + hyaline cartilage

  4. How is the nasal cavity divided?: By the nasal septum

  5. Which bones form the roof and floor of the nasal cavity?: Ethmoid and sphenoid bones; Hard and soft palates

THE NASAL CAVITY Olfactory Mucosa contains olfactory epithelium with smell receptorsRespiratory Mucosa lines the remainder of the nasal cavity Pseudostratified, ciliated, columnar epithelium Mucus and serous secretions contain lysozyme and defensins About 1 quart/day! Cilia move contaminated mucus posteriorly to the throat for swallowing/digestion Cilia are slowed by cold temperatures and harmed by smoking Inspired air is warmed by plexuses of capillaries and veins A rich supply of sensory nerve endings will trigger a sneeze upon contact with irritants

Nasal Conchae § 3 conchae protrude medially from each lateral wall ofthe cavity - superior, middle, and inferior§ Covered in mucosa§ Increase mucosal surface area and turbulence forenhanced warming/filteringNasal Meatus§ The groove inferior to each concha§ Inhalation: air is filtered, warmed, moistened§ Exhalation: heat and moisture are reclaimed

THE PARANASAL SINUSES Form a ring around the nasal cavityLocated in the frontal, sphenoid, ethmoid, and maxillary bonesFunctions: Lighten the skull Give resonance to the voice Produce mucus/warm and moisten the air

THE PHARYNX A muscular tube from the base of the skull to C6Commonly called “the throat”Connects the nasal cavity and mouth to the larynxand esophagusComposed of skeletal muscleThree Regions Nasopharynx Oropharynx Laryngopharynx

NASOPHARYNX Passageway for air posterior to the nasal cavityLined by pseudostratified, columnar epitheliumTypically, the soft palate and uvula close thenasopharynx during swallowingThe posterior wall contains the pharyngeal tonsil(the “adenoids”)Pharyngotympanic Tubes: drain the middle earcavities and allow middle ear pressure to equalizewith atmospheric pressure Protected by the tubal tonsils

  1. What is the function of the nasopharynx?: Passageway for air posterior to the nasal cavity.

  2. What type of epithelium lines the nasopharynx?: Pseudostratified, columnar epithelium.

  3. What closes the nasopharynx during swallowing?: Soft palate and uvula.

  4. What is found on the posterior wall of the nasopharynx?: Pharyngeal tonsil (adenoids).

  5. What is the role of the pharyngotympanic tubes in the nasopharynx?: Drain the middle ear cavities and allow middle ear pressure to equalize with atmospheric pressure.

  6. What protects the pharyngotympanic tubes in the nasopharynx?: Tubal tonsils.

OROPHARYNX Passageway for food AND air – exists from the levelof the soft palate to the epiglottisLined by more protective, stratified, squamousepitheliumThe paired palatine tonsils are embedded in thelateral wallsThe lingual tonsil exists on the posterior surface ofthe tongue

LARYNGOPHARYNX Passageway for food AND airLined by stratified, squamous epitheliumPosterior to the upright epiglottis/larynx,extends to the inferior edge of the cricoidcartilageContinuous with the esophagus

  1. What is the function of the laryngopharynx?: Passageway for food AND air

  2. What type of epithelium lines the laryngopharynx?: Stratified, squamous epithelium

  3. Where does the laryngopharynx extend to?: Inferior edge of the cricoid cartilage

THE LARYNX Commonly called “the voice box”Attaches to the hyoid bone and extends from C3 to C6Continuous with the tracheaServes three functions:§ Provides a patent airway§ Routes air and food into the proper channels§ Produces sound/vocalization – houses the vocal folds


Structurally, an intricate arrangement of 9 cartilages connected by membranes and ligamentsExcept for the epiglottis, all cartilage is hyaline cartilageThyroid Cartilage: large, shaped like a shield Laryngeal Prominence = the Adam’s apple Secondary to the secretion of sex hormones during puberty, it is typically larger in malesCricoid Cartilage: ring-shapedThree small, paired cartilages form the posterior and lateral walls Arytenoid, Cuneiform, CorniculateEpiglottis: flexible, spoon-shaped, elastic cartilage Covers the laryngeal inlet during swallowingCough Reflex: triggered by anything other than air entering the airway


Vocal Ligaments: deep to the laryngeal mucosa, attacharytenoid cartilages to the thyroid cartilage, form the coreof the vocal foldsVocal Folds: true vocal cords§ Vibrate to produce sound as air rushes up§ Lack blood vessels and appear pearly white§ Glottis: the opening between the vocal folds§ Vestibular Folds: false vocal cords§ Lie superiorly to the vocal folds§ Play no part in sound production§ Assist in closing the glottis during swallowing

  1. What are Vocal Ligaments responsible for?: Attaching arytenoid cartilages to the thyroid cartilage and forming the core of the vocal folds.

  2. What is the function of Vocal Folds?: Vibrating to produce sound as air rushes up.

  3. What is the Glottis?: The opening between the vocal folds.

  4. What are Vestibular Folds also known as?: False vocal cords.

  5. What is the role of Vestibular Folds in sound production?: They play no part in sound production but assist in closing the glottis during swallowing.

VOICE PRODUCTION Speech: intermittent release of expired air while opening and closing the glottisVocal Pitch: determined by the length and tension of the vocal cords As the larynx grows, the vocal folds become thicker and longer – the voice deepensVolume: determined by force of air – no vibration with a whisperVocal Quality: determined by the resonating chambers of the pharynx and the oral, nasal, and sinuscavitiesEnunciation: determined by the activity of the muscles of the pharynx, tongue, soft palate, and lipsSphincter Function: vocal folds can act as a sphincter to prevent air passage during the Valsalvamaneuver

  1. How is speech produced?: The intermittent release of expired air while opening and closing the glottis.

  2. What determines vocal pitch?: Determined by the length and tension of the vocal cords.

  3. What determines the volume of the voice?: The force of air, with no vibration during a whisper.

  4. What determines vocal quality?: The resonating chambers of the pharynx and the oral, nasal, and sinus cavities.

  5. What determines enunciation?: The activity of the muscles of the pharynx, tongue, soft palate, and lips.

  6. How can vocal folds act as a sphincter?: A sphincter to prevent air passage during the Valsalva maneuver.

THE TRACHEA Commonly called “the windpipe”Extends from the larynx down to the mediastinumComposed of three layers  Mucosa: ciliated, pseudostratified epithelium with goblet cells Submucosa: connective tissue with seromucous glands Adventitia: connective tissue, encases 16 to 20 C-shaped hyaline cartilage ringsThe trachea is flexible enough to move inferiorly and stretch during inspiration and recoil during exhalation;the cartilage rings prevent collapseThe posterior surface of the tracheal rings are connected by the smooth muscle trachealis – allows theesophagus to expand when food is swallowedCarina: projects posteriorly from the inner surface of the last tracheal cartilage, marks the point where thetrachea branches into the two main bronchi

  1. What is the common name for the trachea?: The windpipe

  2. How many layers is the trachea composed of?: Three layers

  3. What type of epithelium lines the mucosa of the trachea?: Ciliated, pseudostratified epithelium with goblet cells

  4. What is the function of the cartilage rings in the trachea?: Prevent collapse

  5. What muscle connects the posterior surface of the tracheal rings?: Trachealis

  6. What structure marks the point where the trachea branches into the two main bronchi?: Carina

HEIMLICHMANEUVER Created by Henry HeimlichPerformed in response to an obstructed tracheaShould only be used on conscious adults whocannot speak, cough, or breatheManeuver exerts pressure on the diaphragm tocompress the lungs and force air out of theairway

  1. What is the Heimlich maneuver?: A technique created by Henry Heimlich to help with an obstructed trachea.

  2. When should the Heimlich maneuver be performed?: It should only be used on conscious adults who cannot speak, cough, or breathe.

  3. How does the Heimlich maneuver work?: The maneuver exerts pressure on the diaphragm to compress the lungs and force air out of the airway.

THE BRONCHI AND ITS SUBDIVISIONS Air passageways in the lungs branch ~23 times; pattern is called the bronchialtreeThe trachea divides into the right and left main bronchi at about T7Main bronchi plunge into the hilum of each lungThe right main bronchi is wider, shorter, and more vertical than the leftInside the lung, each main bronchi divides into lobar or secondary bronchiHow many lobar/secondary bronchi do you have?Lobar bronchi divide into segmental or tertiary bronchiBronchi less than 1 mm in diameter are called bronchiolesTerminal Bronchioles: the smallest bronchioles, less than .5mm in diameter

RESPIRATORY ZONE STRUCTURES Respiratory Zone: defined by the presence of thin-walled air sacs calledalveoli; begins when the terminal bronchioles feed into respiratorybronchiolesRespiratory Bronchioles -> Alveolar Ducts -> Alveolar Sacs -> Alveoli~300 million alveoli make up most of the volume of each lungAlveoli provide tremendous surface area for gas exchange

RESPIRATORY MEMBRANES External surfaces of the alveoli are densely covered withpulmonary capillariesRespiratory Membrane: alveolar and capillary walls + their fusedbasement membranes only about.5μm thick – gases are exchanged by simple diffusionAlveolar walls are made of a single layer of squamous epithelialcells called type I alveolar cells A sheet of tissue paper is 15x thicker!Type II alveolar cells are scattered, cuboidal cells that secretesurfactant and antimicrobial proteins Surfactant: fluid that contains a detergent-like substance; coatsthe gas-exposed alveolar surfacesAlveolar Macrophages: crawl freely along the internal alveolarsurfaces consuming bacteria, dust, and other debris

  1. What is the composition of the respiratory membrane?: Alveolar and capillary walls + their fused basement membranes

  2. What is the thickness of the respiratory membrane?: Approximately 0.5μm thick

  3. What are the two types of cells that make up the alveolar walls?: Type I alveolar cells and Type II alveolar cells

  4. What is the function of Type II alveolar cells?: They secrete surfactant and antimicrobial proteins

  5. What is the role of surfactant in the alveoli?: It coats the gas-exposed alveolar surfaces

  6. What is the function of Alveolar Macrophages?: They consume bacteria, dust, and other debris along the internal alveolar surfaces


FEATURES OF THE ALVEOLI Surrounded by fine, elastic fibers and pulmonary capillariesAlveolar Pores: openings that connect adjacent alveoli Equalize air pressure throughout the lung Allow for re-routing in the event of collapsed/diseased alveoliAged and dead macrophages get swept up in the ciliary current andcarried to the pharynx - about 2 million/hour

LUNGS Outside of the mediastinum, the lungs fill the thoracic cavityApex: lung’s superior tip, deep to the clavicleBase: lung’s inferior surface, rests on the diaphragmHilum: on the mediastinal surface; site of entry/exit of bloodvessels, bronchi, lymphatic vessels, and nervesThe left lung contains two lobes, and is smaller than the right Cardiac Notch: the concavity/impression of the heart Oblique Fissure: separates the superior and inferior lobesThe right lung contains three lobes, and is larger than the left Horizontal Fissure: separates superior and middle lobes Oblique Fissure: separates the middle and inferior lobes


PLEURAE Pleurae: thin, double layered serosaParietal Pleura: lines the thoracic wall, superior surfaceof the diaphragm, around the heart, and between thelungsVisceral Pleura: lines the external surface of the lungsPleural Cavity: slit-like space between the parietal andvisceral pleuraePleural Fluid: produced by the pleurae, fills the cavity Provides both lubrication and surface tensionThe lungs cling tightly to the thoracic wall – they passivelyexpand and recoil in response to changes in the volumeof the thoracic cavity

PLEURISY Inflammation of the pleurae – causes increasedfrictionTypically results from pneumoniaSymptom: stabbing pain with each breathAs the disease progresses, extra fluid isproduced – friction and pain are reduced, butpressure is exerted on the lungsPleural Effusion: fluid accumulation in thepleural cavity, can sometimes be drainedPLEURISYInflammation of the pleurae – causes increasedfrictionTypically results from pneumoniaSymptom: stabbing pain with each breathAs the disease progresses, extra fluid isproduced – friction and pain are reduced, butpressure is exerted on the lungsPleural Effusion: fluid accumulation in thepleural cavity, can sometimes be drained