https://www.therespiratorysystem.com/glossary/alveolar-ducts-and-sacs/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--alveolar-ducts-and-sacs/hero.webpBranching diagram from terminal bronchiole to respiratory bronchiole, alveolar duct, alveolar sac and alveolushttps://www.therespiratorysystem.com/wp-content/uploads/2017/06/Alveoli.jpgLabeled illustration of a bronchiole ending in an alveolar duct and a grape-like alveolar sac, with pores of Kohn and pulmonary capillarieshttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--alveolar-ducts-and-sacs/duct-vs-sac.webpComparison chart of an alveolar duct and an alveolar sac: shape, airway generation, smooth muscle, air movement and gas exchange https://www.therespiratorysystem.com/glossary/alveolar-macrophages/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--alveolar-macrophages/hero.webpFive-step diagram of how an alveolar macrophage finds, engulfs, digests and carries away an inhaled particlehttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--alveolar-macrophages/jobs-of-alveolar-macrophages.webpCircular diagram of the six main jobs of an alveolar macrophage, from engulfing particles to calming inflammationhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--alveolar-macrophages/alveolar-vs-interstitial-macrophages.webpComparison chart of alveolar macrophages in the air spaces and interstitial macrophages in the alveolar walls https://www.therespiratorysystem.com/alveoli/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/06/Alveoli.jpgLabeled diagram of alveoli showing a bronchiole, alveolar duct, alveolar sac, pores of Kohn, pulmonary arteriole, venule and capillarieshttps://www.therespiratorysystem.com/wp-content/uploads/2017/06/Labeled-Diagram-of-Alveoli-Gas-Exchange.jpgDiagram of gas exchange within an alveolus: oxygen diffuses into a capillary red blood cell while carbon dioxide diffuses into the air space https://www.therespiratorysystem.com/glossary/bohr-effect/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--bohr-effect/hero.webpCycle diagram of the Bohr effect: CO2 and acid from tissues make hemoglobin release oxygen, and CO2 loss in the lungs helps it load oxygenhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--bohr-effect/inside-the-red-blood-cell.webpFive-step diagram of the Bohr effect inside a red blood cell, from carbon dioxide entry to hemoglobin releasing oxygenhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--bohr-effect/bohr-vs-haldane.webpComparison chart of the Bohr effect and the Haldane effect: trigger, what changes, where each helps and which curve shifts https://www.therespiratorysystem.com/bronchi/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/05/Bronchi.jpgLabeled diagram of the bronchi showing the trachea, carina, right and left primary bronchi, lobar and segmental bronchi inside the lungshttps://www.therespiratorysystem.com/wp-content/uploads/2017/05/Bronchus-Anatomy-Diagram.jpgDiagram of a bronchus wall showing cartilage plates, smooth muscle, mucus lining, ciliated lining, blood vessels and the bronchial lumen https://www.therespiratorysystem.com/bronchi-vs-bronchioles/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/bronchi-vs-bronchioles/hero.webpComparison chart of bronchi and bronchioles: size, cartilage, glands, lining, special cells, support and gas exchangehttps://www.therespiratorysystem.com/wp-content/uploads/2017/05/Bronchi.jpgLabeled diagram of the bronchi and bronchioles in both lungs, from the main bronchi to segmental bronchi and small bronchioleshttps://www.therespiratorysystem.com/assets/img/diagrams/bronchi-vs-bronchioles/where-bronchi-become-bronchioles.webpBranching diagram from the trachea and main bronchi to respiratory bronchioles, marking where bronchi become bronchioles https://www.therespiratorysystem.com/bronchial-tree/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/bronchial-tree/hero.webpBranching diagram of the bronchial tree from the trachea through main, lobar and segmental bronchi and bronchioles to the alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/bronchial-tree/right-vs-left.webpComparison chart of the right and left bronchial trees: main bronchus shape, number of lobar and segmental bronchi and nearby vesselshttps://www.therespiratorysystem.com/assets/img/diagrams/bronchial-tree/what-the-tree-does.webpSix-step diagram of the functions of the bronchial tree: conducting, distributing, warming, cleaning, adjusting flow and starting gas exchange https://www.therespiratorysystem.com/bronchioles/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/04/Bronchioles.jpgLabeled diagram of the bronchioles showing a lobular bronchiole, terminal and respiratory bronchioles, alveolar ducts, alveolar sacs and capillaries https://www.therespiratorysystem.com/bronchopulmonary-segments/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/bronchopulmonary-segments/hero.webpComparison diagram of the bronchopulmonary segments of the right lung and the left lung, listed lobe by lobehttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Picture-of-Lung-Segments-Anatomy.jpgColor-coded diagram of the bronchopulmonary segments of both lungs in anterior, posterior and medial viewshttps://www.therespiratorysystem.com/assets/img/diagrams/bronchopulmonary-segments/airway-levels.webpBranching diagram showing where the segmental bronchi sit in the airway tree, from the trachea down to the alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/bronchopulmonary-segments/center-vs-border.webpComparison chart of what lies at the center of a bronchopulmonary segment and at the border between two segments https://www.therespiratorysystem.com/carbon-dioxide-transport/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/carbon-dioxide-transport/hero.webpSix-step diagram of carbon dioxide transport: CO2 enters red blood cells, carbonic anhydrase forms bicarbonate, and the chloride shift followshttps://www.therespiratorysystem.com/assets/img/diagrams/carbon-dioxide-transport/three-forms.webpBar diagram comparing the three forms of carbon dioxide transport: bicarbonate largest, carbamino compounds middle, dissolved gas smallesthttps://www.therespiratorysystem.com/assets/img/diagrams/carbon-dioxide-transport/tissues-vs-lungs.webpComparison chart of carbon dioxide transport in the tissues and in the lungs, showing the reactions running in opposite directions https://www.therespiratorysystem.com/glossary/cardiac-notch/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--cardiac-notch/hero.webpComparison chart of the cardiac notch and the lingula of the left lung: location, lobe, structure and right lung counterparthttps://www.therespiratorysystem.com/wp-content/uploads/2017/11/Lung-Lobes.jpgLabeled diagram of the right and left lungs showing the lobes, fissures and the cardiac notch in the left lunghttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--cardiac-notch/anterior-border.webpFive-step diagram tracing the anterior border of the left lung from the apex past the cardiac notch to the lingula https://www.therespiratorysystem.com/glossary/carina/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--carina/hero.webpBranching diagram showing the trachea dividing at the carina into the right and left main bronchi, then lobar and segmental bronchihttps://www.therespiratorysystem.com/wp-content/uploads/2017/03/Carina-of-Trachea.jpgLabeled illustration of the tracheal bifurcation, with the carina ridge seen inside the trachea between the right and left bronchushttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--carina/carina-cough-trigger.webpFive-step diagram of how irritation of the carina triggers the cough reflex through the vagus nerve and brainstemhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--carina/carina-wall.webpLayer diagram of the carina wall: respiratory epithelium, lamina propria and submucosa, hyaline cartilage and adventitia https://www.therespiratorysystem.com/cilia-and-mucus/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/cilia-and-mucus/hero.webpSix-step diagram of the mucociliary escalator: a particle is trapped in mucus, cilia move the mucus up the airways and it is swallowedhttps://www.therespiratorysystem.com/assets/img/diagrams/cilia-and-mucus/airway-surface-layers.webpLayer diagram of the airway surface: mucus gel layer, periciliary layer, ciliated epithelium, basement membrane and glandshttps://www.therespiratorysystem.com/assets/img/diagrams/cilia-and-mucus/cilia-vs-mucus.webpComparison chart of cilia and mucus in the airways: what each is, which cells make it, its job, location and what goes wrong https://www.therespiratorysystem.com/conducting-zone-vs-respiratory-zone/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/conducting-zone-vs-respiratory-zone/hero.webpAirway tree diagram: conducting zone from trachea to terminal bronchioles, respiratory zone from respiratory bronchioles to alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/conducting-zone-vs-respiratory-zone/zones-compared.webpComparison chart of the conducting zone and the respiratory zone: job, start, end, gas exchange, lining, cleaning and air movementhttps://www.therespiratorysystem.com/assets/img/diagrams/conducting-zone-vs-respiratory-zone/one-breath.webpSix-step diagram of one breath moving through the conducting zone into the respiratory zone and back out https://www.therespiratorysystem.com/control-of-breathing/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/control-of-breathing/hero.webpFeedback loop diagram of breathing control: sensors, brainstem respiratory centers, motor nerves, breathing muscles and blood gaseshttps://www.therespiratorysystem.com/assets/img/diagrams/control-of-breathing/carbon-dioxide-response.webpSix-step diagram showing how rising carbon dioxide acidifies brain fluid, triggers chemoreceptors and increases ventilationhttps://www.therespiratorysystem.com/assets/img/diagrams/control-of-breathing/automatic-vs-voluntary.webpComparison chart of automatic brainstem control of breathing and voluntary cortical control of breathing https://www.therespiratorysystem.com/glossary/dead-space/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--dead-space/hero.webpBranching diagram of the airways showing anatomical dead space from the nose to the terminal bronchioles and the gas exchange zone beyondhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--dead-space/anatomical-vs-physiological.webpComparison chart of anatomical and physiological dead space: what each counts, where, typical size, measurement and causes of increasehttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--dead-space/breathing-patterns.webpBar chart comparing alveolar ventilation with deep slow, normal and shallow fast breathing at the same minute ventilation https://www.therespiratorysystem.com/diaphragm/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/09/Diaphragm.jpgDiaphragm seen from above with central tendon, crura, caval and esophageal openings, aorta, phrenic nerves and lumbar vertebrae labeledhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Diaphragm-Muscle-Location-Picture.jpgFront view of the rib cage showing the diaphragm muscle with its right and left domes, central tendon, esophageal and aortic openingshttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Diaphragm-Function-in-Breathing.jpgSide-by-side diagram of inhalation and exhalation showing the diaphragm flattening and relaxing as the chest and lungs expand and shrink https://www.therespiratorysystem.com/epiglottis/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2016/12/Epiglottis.jpgSide view of the head and neck showing the epiglottis behind the tongue, above the larynx, with the trachea and esophagus belowhttps://www.therespiratorysystem.com/wp-content/uploads/2016/12/Epiglottis-Anatomy-Diagram.jpgAnterior and posterior views of the larynx showing the epiglottis above the hyoid bone and thyroid cartilage, with the tracheal cartilages below https://www.therespiratorysystem.com/ethmoid-sinus/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/ethmoid-sinus/hero.webpComparison chart of the anterior and posterior ethmoid air cells: position, size, drainage, named cells, nerves, arteries and neighborshttps://www.therespiratorysystem.com/assets/img/diagrams/ethmoid-sinus/eye-to-nose.webpLayer diagram from the orbit to the nasal cavity: eye socket, lamina papyracea, ethmoid air cells, medial wall with conchae, nasal cavityhttps://www.therespiratorysystem.com/assets/img/diagrams/ethmoid-sinus/keros-classification.webpBar diagram of the Keros classification showing a shallow type I, medium type II and deep type III olfactory fossa https://www.therespiratorysystem.com/external-and-internal-respiration/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/external-and-internal-respiration/hero.webpComparison chart of external respiration in the lungs and internal respiration in the tissues, with gas directions and oxygen pressureshttps://www.therespiratorysystem.com/assets/img/diagrams/external-and-internal-respiration/four-processes.webpCycle diagram linking pulmonary ventilation, external respiration, gas transport, internal respiration and cellular respirationhttps://www.therespiratorysystem.com/assets/img/diagrams/external-and-internal-respiration/internal-respiration-steps.webpSix-step diagram of internal respiration from arterial blood arriving in a tissue to oxygen-poor venous blood returning to the heart https://www.therespiratorysystem.com/frontal-sinus/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/frontal-sinus/hero.webpLayer diagram from the forehead inward: skin and muscle, anterior table, frontal sinus air space, posterior table, dura and frontal lobehttps://www.therespiratorysystem.com/assets/img/diagrams/frontal-sinus/frontal-sinus-drainage.webpSix-step diagram of frontal sinus drainage: mucus moves through the funnel-shaped floor, ostium and frontal recess into the middle meatus https://www.therespiratorysystem.com/respiratory-system-functions/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/10/Trace-the-Airflow-Pathway-Through-the-Respiratory-System.jpgDiagram of the pathway of air through the respiratory system, from the nostrils and nasal cavity down the trachea and bronchi to the alveolihttps://www.therespiratorysystem.com/wp-content/uploads/2017/10/Respiratory-System-Functions.jpgLabeled chart of respiratory system functions naming the job of the nasal cavity, pharynx, larynx, trachea, bronchi, alveoli and diaphragm https://www.therespiratorysystem.com/gas-exchange/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/gas-exchange/hero.webpDiagram of gas exchange between an alveolus and a pulmonary capillary: oxygen diffuses into the blood and carbon dioxide diffuses outhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Gas-Exchange-in-the-Lungs-Image.jpgLabeled illustration of alveoli and their capillaries, with a close-up of oxygen entering red blood cells and carbon dioxide leaving themhttps://www.therespiratorysystem.com/assets/img/diagrams/gas-exchange/oxygen-pathway.webpSix-step diagram of the path of an oxygen molecule from an alveolus across the respiratory membrane to hemoglobin in a red blood cellhttps://www.therespiratorysystem.com/assets/img/diagrams/gas-exchange/lungs-vs-tissues.webpComparison chart of gas exchange in the lungs (external respiration) and in the tissues (internal respiration) https://www.therespiratorysystem.com/glossary/glottis/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--glottis/hero.webpComparison chart of the open glottis during breathing and the closed glottis during speech, coughing and swallowinghttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--glottis/levels-of-the-larynx.webpLayered diagram of the levels of the larynx from the laryngeal inlet and supraglottis to the glottis, subglottis and trachea https://www.therespiratorysystem.com/epiglottis-vs-glottis/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/epiglottis-vs-glottis/hero.webpComparison chart of the epiglottis and the glottis: what each is, position in the larynx, tissue, movement and main jobhttps://www.therespiratorysystem.com/assets/img/diagrams/epiglottis-vs-glottis/larynx-top-to-bottom.webpLayered diagram of the larynx from top to bottom: epiglottis, laryngeal inlet, vestibule and vestibular folds, glottis and subglottishttps://www.therespiratorysystem.com/assets/img/diagrams/epiglottis-vs-glottis/swallowing-closure.webpSix-step diagram of airway closure during swallowing: glottis, vestibular folds, laryngeal elevation and epiglottis https://www.therespiratorysystem.com/hilum-of-lung/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/hilum-of-lung/hero.webpComparison diagram of the right and left lung hila showing the position of the bronchus, pulmonary artery, pulmonary veins and nearby structureshttps://www.therespiratorysystem.com/assets/img/diagrams/hilum-of-lung/front-to-back.webpLayered diagram of the lung root showing pulmonary veins in front, pulmonary artery in the middle and bronchus at the backhttps://www.therespiratorysystem.com/assets/img/diagrams/hilum-of-lung/hilum-vs-root.webpComparison chart explaining the difference between the hilum of the lung and the root of the lung https://www.therespiratorysystem.com/respiratory-and-circulatory-system/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-and-circulatory-system/hero.webpCycle diagram of how the respiratory and circulatory systems work together: lungs, left heart, body tissues and right heart in one loophttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-and-circulatory-system/respiratory-vs-circulatory-compare.webpComparison chart of the respiratory system and the circulatory system: job, organs, what flows, pump, exchange site and controlhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-and-circulatory-system/oxygen-journey.webpSix-step diagram of an oxygen molecule traveling from inhaled air through the lungs, blood and heart to a muscle cellhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Gas-Exchange-in-the-Lungs-Image.jpgIllustration of alveoli wrapped in pulmonary capillaries, with oxygen entering and carbon dioxide leaving red blood cells https://www.therespiratorysystem.com/how-the-voice-is-produced/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/how-the-voice-is-produced/hero.webpSix-step diagram of phonation: breath in, vocal folds close, pressure builds, folds vibrate, air puffs make a tone, the vocal tract shapes ithttps://www.therespiratorysystem.com/assets/img/diagrams/how-the-voice-is-produced/vibration-cycle.webpCycle diagram of one vocal fold vibration: closed, pressure rises, folds open, a puff of air escapes, folds snap shuthttps://www.therespiratorysystem.com/assets/img/diagrams/how-the-voice-is-produced/phonation-vs-resonance.webpComparison chart of phonation and resonance: where each happens, what each controls and which structures are involved https://www.therespiratorysystem.com/inhalation-and-exhalation/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/inhalation-and-exhalation/hero.webpBreathing cycle diagram: the diaphragm contracts and air flows in, then the muscles relax, the lungs recoil and air flows outhttps://www.therespiratorysystem.com/assets/img/diagrams/inhalation-and-exhalation/inhalation-steps.webpSix-step inhalation process diagram from the brain signal and diaphragm contraction to air flowing into the alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/inhalation-and-exhalation/inhalation-vs-exhalation-chart.webpInhalation vs exhalation comparison chart showing the diaphragm, ribs, chest volume, pressure and airflow in each phase https://www.therespiratorysystem.com/laryngeal-cartilages/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/laryngeal-cartilages/hero.webpComparison chart of the 3 unpaired and 3 paired laryngeal cartilages: members, number, size, tissue, job and jointshttps://www.therespiratorysystem.com/wp-content/uploads/2016/11/Larynx-Anatomy.jpgAnterior, side and posterior views of the larynx showing the epiglottis, thyroid, cricoid and arytenoid cartilages and the vocal cordshttps://www.therespiratorysystem.com/assets/img/diagrams/laryngeal-cartilages/how-muscles-move-the-cartilages.webpSix-step diagram of how laryngeal muscles move the arytenoid, thyroid and epiglottic cartilages to open, close and tense the vocal cords https://www.therespiratorysystem.com/laryngopharynx/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/laryngopharynx/hero.webpStacked diagram of the pharynx showing the nasopharynx, oropharynx and laryngopharynx from top to bottom, ending where the larynx and esophagus splithttps://www.therespiratorysystem.com/assets/img/diagrams/laryngopharynx/swallow-through-the-laryngopharynx.webpSix-step diagram of a swallow through the laryngopharynx, from the larynx rising and the airway sealing to food entering the esophagushttps://www.therespiratorysystem.com/assets/img/diagrams/laryngopharynx/larynx-vs-laryngopharynx.webpComparison chart of the larynx and the laryngopharynx by name, position, what each carries, framework, lining, job and where each leads https://www.therespiratorysystem.com/larynx/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2016/11/Larynx-Diagram.jpgSide view of the head and neck showing the larynx with its supraglottis, glottis, vocal cord and subglottis between the epiglottis and tracheahttps://www.therespiratorysystem.com/wp-content/uploads/2016/11/Larynx-Anatomy.jpgAnterior, side and posterior views of the larynx with the epiglottis, hyoid bone, thyroid and cricoid cartilages, vocal cords and tracheal rings https://www.therespiratorysystem.com/larynx-vs-pharynx/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/larynx-vs-pharynx/hero.webpComparison chart of the pharynx (throat) and larynx (voice box): what passes, position, length, structure, parts and jobshttps://www.therespiratorysystem.com/wp-content/uploads/2016/09/Pharynx.jpgLabeled side view of the head and neck showing the nasopharynx, oropharynx and laryngopharynx, with the larynx in front and the esophagus behindhttps://www.therespiratorysystem.com/assets/img/diagrams/larynx-vs-pharynx/front-to-back.webpLayered diagram from the front to the back of the neck: strap muscles, larynx, laryngopharynx, pharyngeal muscle wall and cervical vertebrae https://www.therespiratorysystem.com/left-lung/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/left-lung/hero.webpDiagram of the left lung from apex to base: superior lobe, cardiac notch, lingula, oblique fissure and inferior lobehttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Lungs.jpgLabeled front view of both lungs showing the left lung's cardiac notch, oblique fissure, left primary bronchus and pleurahttps://www.therespiratorysystem.com/assets/img/diagrams/left-lung/lingula-vs-middle-lobe.webpComparison chart of the lingula of the left lung and the middle lobe of the right lung: lobe, fissures, segments, airway and position https://www.therespiratorysystem.com/category/lower-respiratory-tract/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/12/Lower-Respiratory-Tract.jpgLabeled diagram of the lower respiratory tract: trachea, bronchi, bronchioles, alveoli and the lobes of both lungshttps://www.therespiratorysystem.com/wp-content/themes/Respiratory/images/respiratory-system-diagram.jpgLabeled respiratory system diagram marking the lower respiratory tract: trachea, primary bronchi, bronchioles, alveoli, lung lobes and diaphragm https://www.therespiratorysystem.com/glossary/lung-fissures/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--lung-fissures/hero.webpComparison chart of the oblique and horizontal fissures of the lungs: other names, which lung, lobes separated and chest wall landmarkshttps://www.therespiratorysystem.com/wp-content/uploads/2017/11/Lung-Lobes.jpgLabeled diagram of the right and left lungs showing the horizontal fissure, both oblique fissures, the lobes and the cardiac notchhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--lung-fissures/tracing-the-fissures.webpFour-step diagram showing how the oblique and horizontal lung fissures are traced on the back, side and front of the chest wall https://www.therespiratorysystem.com/lung-volumes-and-capacities/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/lung-volumes-and-capacities/hero.webpBar chart comparing the relative sizes of the four lung volumes and the four lung capacities in a typical adulthttps://www.therespiratorysystem.com/assets/img/diagrams/lung-volumes-and-capacities/lung-volume-layers.webpDiagram of total lung capacity divided into four stacked volumes: inspiratory reserve, tidal, expiratory reserve and residual volumehttps://www.therespiratorysystem.com/assets/img/diagrams/lung-volumes-and-capacities/minute-vs-alveolar-ventilation.webpComparison chart of minute ventilation and alveolar ventilation: definition, formula, typical resting value and dead space https://www.therespiratorysystem.com/lungs/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/09/Lungs.jpgLabeled diagram of the human lungs showing the trachea, primary bronchi, lobes, fissures, cardiac notch, pleura and diaphragmhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Picture-of-Lung-Segments-Anatomy.jpgSegmental anatomy of the lungs in anterior, posterior and medial views, with each bronchopulmonary segment color coded and labeledhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Gas-Exchange-in-the-Lungs-Image.jpgDiagram of gas exchange in an alveolus: oxygen moves from the air into capillary blood while carbon dioxide moves into the alveolus https://www.therespiratorysystem.com/maxillary-sinus/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/maxillary-sinus/hero.webpSix-step diagram of maxillary sinus drainage: mucus swept upward by cilia through the ostium and infundibulum into the middle meatushttps://www.therespiratorysystem.com/assets/img/diagrams/maxillary-sinus/sinus-and-teeth.webpLayer diagram from the maxillary sinus down to the mouth: sinus lining, bony floor, roots of the upper back teeth, alveolar bone and gumshttps://www.therespiratorysystem.com/assets/img/diagrams/maxillary-sinus/maxillary-vs-sphenoid.webpComparison chart of the maxillary sinus and the sphenoid sinus: location, bone, size, drainage, neighbors and development https://www.therespiratorysystem.com/mechanics-of-breathing/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/mechanics-of-breathing/hero.webpSix-step diagram of the mechanics of breathing: muscles enlarge the chest, alveolar pressure falls, air flows in, then recoil pushes air outhttps://www.therespiratorysystem.com/assets/img/diagrams/mechanics-of-breathing/pleural-coupling.webpLayered diagram from chest wall to parietal pleura, pleural fluid, visceral pleura and lung tissue, showing how the lung follows the chesthttps://www.therespiratorysystem.com/assets/img/diagrams/mechanics-of-breathing/quiet-vs-forced.webpComparison chart of quiet breathing and forced breathing: muscles used, expiration, diaphragm movement, pressures and volumes https://www.therespiratorysystem.com/mediastinum/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/mediastinum/hero.webpDiagram of the divisions of the mediastinum: superior mediastinum above the sternal angle and inferior mediastinum below it, with borders and contentshttps://www.therespiratorysystem.com/assets/img/diagrams/mediastinum/inferior-front-to-back.webpLayered diagram of the inferior mediastinum from front to back: anterior, middle and posterior mediastinum with their main contentshttps://www.therespiratorysystem.com/assets/img/diagrams/mediastinum/mediastinum-vs-pericardial-cavity.webpComparison chart of the mediastinum and the pericardial cavity showing that the pericardial cavity lies inside the middle mediastinum https://www.therespiratorysystem.com/muscles-of-respiration/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/muscles-of-respiration/hero.webpCycle diagram of the muscles of respiration: diaphragm and external intercostals contract, air flows in, muscles relax, air flows outhttps://www.therespiratorysystem.com/wp-content/uploads/2018/05/Intercostal-Muscles-Function.jpgLabeled diagram of the rib cage during inhalation and exhalation, showing the intercostal muscles, ribs and diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/muscles-of-respiration/inspiration-vs-expiration.webpComparison chart of the muscles used for breathing in and breathing out during quiet and forced breathing https://www.therespiratorysystem.com/nasal-cavity/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/07/Nasal-Cavity.jpgLabeled side-view diagram of the nasal cavity with the conchae, meatuses, olfactory region, hard palate and nasopharynxhttps://www.therespiratorysystem.com/wp-content/uploads/2017/07/Nasal-Cavity-Bones-Diagram.jpgDiagram of the bones forming the walls of the nasal cavity, including the ethmoid, sphenoid, maxilla, palatine and nasal bones https://www.therespiratorysystem.com/nasal-septum/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/nasal-septum/hero.webpFive-step diagram of the nasal septum from front to back: membranous septum, septal cartilage, perpendicular plate of the ethmoid and vomerhttps://www.therespiratorysystem.com/wp-content/uploads/2017/12/Bones-and-Cartilages-in-the-Nose.jpgSide view of the nose showing the septal cartilage, perpendicular plate of the ethmoid, vomer and vomeronasal cartilage of the nasal septumhttps://www.therespiratorysystem.com/assets/img/diagrams/nasal-septum/septum-vs-vomer.webpComparison chart of the nasal septum and the vomer: what each is, what it is made of, its position and flexibilityhttps://www.therespiratorysystem.com/assets/img/diagrams/nasal-septum/septum-layers.webpLayer diagram of the nasal septum: respiratory epithelium, lamina propria, perichondrium and the cartilage or bone core https://www.therespiratorysystem.com/nose/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/12/External-Nose.jpgLabeled diagram of the external nose showing the root, bridge, dorsum, apex, alae and nostrilshttps://www.therespiratorysystem.com/wp-content/uploads/2017/12/Bones-and-Cartilages-in-the-Nose.jpgDiagram of the bones and cartilages of the nose: nasal bones, maxilla, lateral cartilage, septal cartilage and alar cartilageshttps://www.therespiratorysystem.com/wp-content/uploads/2017/12/Nose-Anatomy-Diagram.jpgSide-view cross section of the nose showing the nasal cavity, superior, middle and inferior conchae, sinuses and nasopharynx https://www.therespiratorysystem.com/diaphragm-openings/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/diaphragm-openings/hero.webpDiagram of the three main openings of the diaphragm: caval opening at T8, esophageal hiatus at T10 and aortic hiatus at T12, with their contentshttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Diaphragm.jpgLabeled view of the diaphragm from below showing the inferior vena cava, esophageal hiatus, aorta, thoracic duct, crura and phrenic nerveshttps://www.therespiratorysystem.com/assets/img/diagrams/diaphragm-openings/esophageal-vs-aortic-hiatus.webpComparison chart of the esophageal hiatus and the aortic hiatus: level, what forms them, contents and behavior when the diaphragm contracts https://www.therespiratorysystem.com/respiratory-system-organs/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-organs/hero.webpDiagram listing the organs of the respiratory system in airflow order, from the nose to the alveoli, with the diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-organs/upper-vs-lower-organs.webpComparison chart of upper respiratory tract organs and lower respiratory tract organs, their location and main jobshttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-organs/chest-wall-to-lung.webpLayer diagram from the rib cage through the parietal pleura, pleural cavity and visceral pleura to the lung tissue https://www.therespiratorysystem.com/oropharynx/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/oropharynx/hero.webpDiagram of the nasal cavity, nasopharynx, oropharynx and laryngopharynx in order, showing where air and food passhttps://www.therespiratorysystem.com/wp-content/uploads/2016/09/Pharynx.jpgSide view of the head showing the nasopharynx, oropharynx and laryngopharynx behind the nasal cavity, mouth and larynxhttps://www.therespiratorysystem.com/assets/img/diagrams/oropharynx/oral-cavity-vs-oropharynx.webpComparison chart of the oral cavity and the oropharynx: location, tract, part of the tongue, lymphoid tissue, nerve and main jobshttps://www.therespiratorysystem.com/assets/img/diagrams/oropharynx/oropharynx-wall-layers.webpLayer diagram of the oropharyngeal wall from the mucosa through the submucosa, pharyngobasilar fascia and muscles to the buccopharyngeal fascia https://www.therespiratorysystem.com/oxygen-transport/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/oxygen-transport/hero.webpOxygen transport cycle diagram: hemoglobin loads oxygen in the lungs, carries it in the arteries, unloads it in the tissues and returns in the veinshttps://www.therespiratorysystem.com/assets/img/diagrams/oxygen-transport/hemoglobin-structure.webpLayered diagram from a red blood cell to a hemoglobin molecule, globin chain, heme group and the iron atom that binds oxygenhttps://www.therespiratorysystem.com/assets/img/diagrams/oxygen-transport/oxyhemoglobin-vs-deoxyhemoglobin.webpComparison chart of oxyhemoglobin and deoxyhemoglobin: oxygen bound, color, where each is found, shape and affinity https://www.therespiratorysystem.com/oxygen-hemoglobin-dissociation-curve/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/oxygen-hemoglobin-dissociation-curve/hero.webpBar diagram of hemoglobin oxygen saturation leaving the lungs, in resting venous blood, at half saturation, in working muscle and at very low oxygenhttps://www.therespiratorysystem.com/assets/img/diagrams/oxygen-hemoglobin-dissociation-curve/cooperative-binding.webpSix-step diagram of cooperative oxygen binding to hemoglobin, explaining the flat start, steep middle and plateau of the S-shaped curvehttps://www.therespiratorysystem.com/assets/img/diagrams/oxygen-hemoglobin-dissociation-curve/right-vs-left-shift.webpComparison chart of a right shift and a left shift of the oxygen-hemoglobin dissociation curve, with causes and effects https://www.therespiratorysystem.com/paranasal-sinuses/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2018/03/Paranasal-Sinuses.jpgFront and side views of a face labeling the frontal, ethmoid, maxillary and sphenoid sinuses, the nasal cavity and the mucus membranehttps://www.therespiratorysystem.com/wp-content/uploads/2018/03/Paranasal-Sinuses-in-X-Ray-Image.jpgFront-facing skull X-ray with the dark air-filled frontal, ethmoid, maxillary and sphenoid sinuses labeled on both sideshttps://www.therespiratorysystem.com/wp-content/uploads/2018/03/Drainage-of-the-Sinus-Cavities-Diagram.jpgSide view of the lateral nasal wall showing where the frontal, ethmoid, maxillary and sphenoid sinuses open into the nasal cavity https://www.therespiratorysystem.com/pathway-of-air/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/pathway-of-air/hero.webpEight-step diagram of the pathway of air: nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles and alveolihttps://www.therespiratorysystem.com/wp-content/uploads/2017/10/Trace-the-Airflow-Pathway-Through-the-Respiratory-System.jpgLabeled diagram tracing the pathway of air from the nostrils and mouth through the pharynx, larynx, trachea and bronchi to the alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/pathway-of-air/branching-airways.webpBranching diagram of the airways from the trachea through the main, lobar and segmental bronchi to the bronchioles and alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/pathway-of-air/breathing-in-vs-out.webpComparison chart of inhaled and exhaled air: direction along the pathway, muscles, lung pressure, oxygen, carbon dioxide and moisture https://www.therespiratorysystem.com/pharynx/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2016/09/Pharynx.jpgSide view of the head and neck labeling the nasopharynx, oropharynx and laryngopharynx, with the soft palate, epiglottis, larynx and esophagus https://www.therespiratorysystem.com/phrenic-nerve/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/phrenic-nerve/hero.webpSix-step diagram of the phrenic nerve course from the C3 to C5 roots in the neck, through the chest beside the heart, to the diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/phrenic-nerve/right-vs-left.webpComparison chart of the right and left phrenic nerves: length, path in the upper chest, relation to the heart and where each enters the diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/phrenic-nerve/breathing-control-loop.webpCycle diagram of breathing control: brainstem, phrenic motor neurons, phrenic nerve, diaphragm contraction, airflow and feedback https://www.therespiratorysystem.com/pleura/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/pleura/hero.webpLayered diagram of the pleura from the chest wall inward: endothoracic fascia, parietal pleura, pleural cavity, visceral pleura and lunghttps://www.therespiratorysystem.com/assets/img/diagrams/pleura/visceral-vs-parietal-pleura.webpComparison chart of the visceral pleura and the parietal pleura: location, parts, origin, nerve and blood supply https://www.therespiratorysystem.com/pneumocytes/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/pneumocytes/hero.webpComparison chart of type I and type II pneumocytes: shape, share of alveolar surface, position, main job and role in repairhttps://www.therespiratorysystem.com/assets/img/diagrams/pneumocytes/surface-vs-number.webpBar chart showing that type I pneumocytes cover nearly all of the alveolar surface while type II pneumocytes are the more numerous cellshttps://www.therespiratorysystem.com/assets/img/diagrams/pneumocytes/alveolar-repair.webpFive-step diagram of alveolar repair in which type II pneumocytes divide, spread and flatten into new type I pneumocytes https://www.therespiratorysystem.com/pulmonary-circulation/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/pulmonary-circulation/hero.webpSix-step diagram of the pulmonary circulation pathway from the right ventricle through the lungs to the left atriumhttps://www.therespiratorysystem.com/assets/img/diagrams/pulmonary-circulation/pulmonary-artery-branches.webpBranching diagram of the pulmonary arteries from the pulmonary trunk to lobar and segmental arteries, arterioles and alveolar capillarieshttps://www.therespiratorysystem.com/assets/img/diagrams/pulmonary-circulation/pulmonary-vs-systemic.webpComparison chart of pulmonary circulation and systemic circulation: chambers, blood oxygen, pressure, resistance and response to low oxygen https://www.therespiratorysystem.com/glossary/pulmonary-lobule/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--pulmonary-lobule/hero.webpNested diagram of lung units from lung to lobe, segment, secondary pulmonary lobule, acinus and alveolushttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--pulmonary-lobule/airways-inside-a-lobule.webpBranching diagram of airways inside a pulmonary lobule, from the lobular bronchiole to respiratory bronchioles and alveolar sacshttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--pulmonary-lobule/lobule-vs-acinus.webpComparison chart of the pulmonary lobule and the pulmonary acinus: definition, size, entering airway, contents and zone https://www.therespiratorysystem.com/pulmonary-surfactant/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/pulmonary-surfactant/hero.webpComparison chart of alveoli with and without pulmonary surfactant: surface tension, collapse, effort to inflate and fluid in the air sacshttps://www.therespiratorysystem.com/assets/img/diagrams/pulmonary-surfactant/surfactant-life-cycle.webpCycle diagram of the surfactant life cycle: made in type II cells, stored in lamellar bodies, secreted, spread as a film, taken back up and recycledhttps://www.therespiratorysystem.com/assets/img/diagrams/pulmonary-surfactant/where-surfactant-sits.webpLayered diagram showing the surfactant film and hypophase on top of the alveolar epithelium, basement membrane and capillary wall https://www.therespiratorysystem.com/respiratory-chemoreceptors/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-chemoreceptors/hero.webpFeedback loop diagram: rising carbon dioxide is detected by chemoreceptors, the medulla increases breathing, and carbon dioxide returns to normalhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-chemoreceptors/glomus-cell-steps.webpSix-step diagram of how a carotid body glomus cell detects low oxygen and signals the brainstem to increase breathinghttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-chemoreceptors/central-vs-peripheral.webpComparison chart of central and peripheral chemoreceptors: location, stimulus, response to low oxygen, speed and nerve pathway https://www.therespiratorysystem.com/respiratory-diseases/2026-11-02https://www.therespiratorysystem.com/wp-content/themes/Respiratory/images/respiratory-system-diagram.jpgLabeled diagram of the respiratory system marking the upper tract (nose, sinuses, pharynx, larynx) and lower tract (trachea, bronchi, lungs) https://www.therespiratorysystem.com/respiratory-epithelium/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-epithelium/hero.webpLayer diagram of the respiratory mucosa: mucus, periciliary fluid, pseudostratified ciliated epithelium, basement membrane, lamina propriahttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-epithelium/ciliated-vs-goblet.webpComparison chart of ciliated columnar cells and goblet cells in the respiratory epithelium: shape, surface, product and jobhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-epithelium/lining-along-the-airways.webpBranching diagram showing how the airway lining changes from pseudostratified in the trachea to simple squamous in the alveoli https://www.therespiratorysystem.com/respiratory-membrane/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-membrane/hero.webpLayered diagram of the respiratory membrane from alveolar air to capillary blood, showing its six layers from surfactant film to endotheliumhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-membrane/thin-vs-thick-side.webpComparison chart of the thin side and the thick side of the blood-air barrier around a lung capillaryhttps://www.therespiratorysystem.com/wp-content/uploads/2017/06/Labeled-Diagram-of-Alveoli-Gas-Exchange.jpgLabeled diagram of an alveolus beside a capillary, with the alveolar epithelium, capillary wall, surfactant and gas diffusion https://www.therespiratorysystem.com/respiratory-physiology/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-physiology/hero.webpFive-step diagram of respiratory physiology: ventilation, external respiration, gas transport, internal respiration and cellular respirationhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-physiology/lung-volumes-bars.webpBar chart comparing the relative sizes of tidal volume, expiratory reserve volume, residual volume and inspiratory reserve volumehttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-physiology/breathing-control-loop.webpCycle diagram of breathing control: rising carbon dioxide is sensed, the brainstem drives deeper breathing and carbon dioxide falls https://www.therespiratorysystem.com/respiratory-system-diagram/2026-11-02https://www.therespiratorysystem.com/wp-content/themes/Respiratory/images/respiratory-system-diagram.jpgLabeled respiratory system diagram showing the nasal cavity, pharynx, larynx, trachea, bronchi, both lungs with their lobes, alveoli and the diaphragmhttps://www.therespiratorysystem.com/wp-content/uploads/2015/12/Upper-Respiratory-Tract.jpgSide-view upper respiratory tract diagram labeling the nasal cavity, sinuses, palate, oral cavity, pharynx, larynx and vocal cordshttps://www.therespiratorysystem.com/wp-content/uploads/2015/12/Lower-Respiratory-Tract.jpgLower respiratory tract diagram labeling the larynx, trachea, primary bronchi, both lungs, bronchioles, alveolar sac, alveoli, ribs and diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-diagram/airway-branches.webpBranching chart of the airways in a respiratory system diagram, from the trachea through the bronchi and bronchioles to the alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-diagram/how-to-label.webpSix-step guide to labeling a respiratory system diagram in the order air flows, from the nostrils to the alveoli and diaphragm https://www.therespiratorysystem.com/respiratory-system-facts/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-facts/hero.webpComparison chart of inhaled and exhaled air: oxygen, carbon dioxide, nitrogen, water vapor and temperaturehttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-facts/airway-branching.webpBranching diagram of the airways from the trachea through the bronchi and bronchioles to the alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-facts/breathing-rate-by-age.webpBar chart showing that resting breathing rate is fastest in newborns and slows through childhood to the adult rate https://www.therespiratorysystem.com/respiratory-system-histology/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-histology/hero.webpBranching diagram of respiratory system histology from the trachea to the alveoli, showing how cartilage, glands and epithelium changehttps://www.therespiratorysystem.com/wp-content/uploads/2017/03/Trachea-Cross-Section-Anatomy.jpgLabeled cross section of the trachea showing the pseudostratified epithelium, submucosa, hyaline cartilage ring, trachealis muscle and adventitiahttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-histology/airway-wall-layers.webpLayer diagram of the tracheal wall from the adventitia through hyaline cartilage, submucosa and lamina propria to the respiratory epithelium https://www.therespiratorysystem.com/respiratory-system-quiz/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-quiz/hero.webpSix-step study map for a respiratory system quiz: label the parts, know each job, tissues, breathing, gas transport and lung volumeshttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-quiz/inhalation-vs-exhalation.webpComparison chart of breathing in and quiet breathing out: diaphragm, intercostal muscles, chest volume, lung pressure, airflow and energyhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-quiz/lung-volumes-bars.webpBar chart comparing the relative sizes of tidal volume, expiratory and inspiratory reserve, residual volume, vital capacity and total lung capacity https://www.therespiratorysystem.com/respiratory-system-worksheet/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-worksheet/hero.webpRespiratory system labeling worksheet with eight blank lines and a clue for each stop on the path of air, from nostrils to alveolihttps://www.therespiratorysystem.com/wp-content/uploads/2017/10/Trace-the-Airflow-Pathway-Through-the-Respiratory-System.jpgLabeled diagram of the pathway of air through the respiratory system, from the nostrils and nasal cavity to the bronchioles and alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-worksheet/breathing-cycle-key.webpCycle diagram of one breath: the diaphragm contracts, the chest enlarges and air flows in, then the diaphragm relaxes and air flows out https://www.therespiratorysystem.com/rib-cage/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/rib-cage/hero.webpSix-step diagram of how the rib cage, diaphragm and intercostal muscles enlarge the chest during inhalationhttps://www.therespiratorysystem.com/assets/img/diagrams/rib-cage/pump-handle-vs-bucket-handle.webpComparison chart of the pump-handle and bucket-handle movements of the ribs during breathing https://www.therespiratorysystem.com/right-lung/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/right-lung/hero.webpDiagram of the right lung from apex to base: superior lobe, horizontal fissure, middle lobe, oblique fissure and inferior lobehttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Picture-of-Lung-Segments-Anatomy.jpgSegmental anatomy of the lungs in anterior, posterior and medial views, with the right lung's ten segments color coded and labeledhttps://www.therespiratorysystem.com/assets/img/diagrams/right-lung/right-lobe-sizes.webpBar chart comparing the relative size of the right inferior, superior and middle lobes, from largest to smallest https://www.therespiratorysystem.com/sense-of-smell/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/sense-of-smell/hero.webpSix-step diagram of how we smell: odorants are inhaled, dissolve in nasal mucus, bind receptors and signal the olfactory bulb and brainhttps://www.therespiratorysystem.com/assets/img/diagrams/sense-of-smell/olfactory-layers.webpLayer diagram of the olfactory region: mucus, olfactory epithelium, lamina propria, cribriform plate and olfactory bulbhttps://www.therespiratorysystem.com/assets/img/diagrams/sense-of-smell/respiratory-vs-olfactory.webpComparison chart of respiratory epithelium and olfactory epithelium: location, job, cells, cilia, mucus source and color https://www.therespiratorysystem.com/sphenoid-sinus/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/sphenoid-sinus/hero.webpStep diagram tracing the route from the nostril through the upper nasal cavity and sphenoethmoidal recess to the sphenoid sinushttps://www.therespiratorysystem.com/assets/img/diagrams/sphenoid-sinus/sphenoid-sinus-lining.webpLayer diagram of the sphenoid sinus wall from the bone through periosteum, lamina propria and ciliated epithelium to the mucus layerhttps://www.therespiratorysystem.com/assets/img/diagrams/sphenoid-sinus/sphenoid-vs-maxillary.webpComparison chart of the sphenoid sinus and the maxillary sinus by bone, position, size, drainage, neighbors and development https://www.therespiratorysystem.com/glossary/terminal-and-respiratory-bronchioles/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--terminal-and-respiratory-bronchioles/hero.webpBranching diagram from small bronchi through lobular, terminal and respiratory bronchioles to alveolar ducts and sacshttps://www.therespiratorysystem.com/wp-content/uploads/2017/04/Bronchioles.jpgLabeled illustration of a lobular bronchiole dividing into terminal and respiratory bronchioles, alveolar ducts and alveolar sacshttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--terminal-and-respiratory-bronchioles/terminal-bronchiole-wall.webpLayer diagram of a terminal bronchiole wall: adventitia, smooth muscle, lamina propria and cuboidal epithelium with club cellshttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--terminal-and-respiratory-bronchioles/terminal-vs-respiratory.webpComparison chart of terminal bronchioles and respiratory bronchioles: zone, alveoli, gas exchange, lining and smooth muscle https://www.therespiratorysystem.com/2026-11-02https://www.therespiratorysystem.com/wp-content/themes/Respiratory/images/respiratory-system-diagram.jpgRespiratory system diagram https://www.therespiratorysystem.com/respiratory-system-for-kids/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-for-kids/hero.webpSix-step kids diagram of the path of air: nose or mouth, throat, voice box, windpipe, bronchi and air sacs in the lungshttps://www.therespiratorysystem.com/wp-content/uploads/2017/10/Trace-the-Airflow-Pathway-Through-the-Respiratory-System.jpgLabeled picture of the respiratory system: nasal cavity, mouth, pharynx, larynx, trachea, bronchi, lungs, alveoli and diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-for-kids/breathing-in-vs-out.webpKids comparison chart of breathing in and breathing out: what the diaphragm, ribs, chest and lungs dohttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-for-kids/air-sac-swap.webpKids diagram of an air sac next to a tiny blood vessel: oxygen moves into the blood and carbon dioxide moves out https://www.therespiratorysystem.com/thoracic-cavity/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/thoracic-cavity/hero.webpComparison diagram of the three compartments of the thoracic cavity: the two pleural cavities and the mediastinumhttps://www.therespiratorysystem.com/assets/img/diagrams/thoracic-cavity/chest-wall-layers.webpLayered diagram of the chest wall from the skin inward: skin, muscles, ribs and intercostal muscles, endothoracic fascia, parietal pleurahttps://www.therespiratorysystem.com/assets/img/diagrams/thoracic-cavity/thoracic-vs-abdominal-cavity.webpComparison chart of the thoracic cavity and the abdominal cavity: position, walls, lining, organs and changes during breathing https://www.therespiratorysystem.com/tidal-volume/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/tidal-volume/hero.webpCycle diagram of one tidal breath: diaphragm contracts, about 500 mL flows in, muscles relax, air flows out, lungs return to FRChttps://www.therespiratorysystem.com/assets/img/diagrams/tidal-volume/tidal-volume-vs-lung-volumes.webpBar chart showing tidal volume as a small fraction of the reserve volumes, residual volume and vital capacity of an adulthttps://www.therespiratorysystem.com/assets/img/diagrams/tidal-volume/rest-vs-exercise.webpComparison chart of tidal volume, breathing rate, ventilation and breathing muscles at quiet rest and during hard exercise 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systemhttps://www.therespiratorysystem.com/assets/img/diagrams/esophagus-vs-trachea/front-to-back.webpLayer diagram of the neck from front to back: skin and strap muscles, thyroid gland, trachea, esophagus and vertebral columnhttps://www.therespiratorysystem.com/assets/img/diagrams/esophagus-vs-trachea/swallowing.webpSix-step diagram of swallowing showing how the airway closes and food enters the esophagus instead of the trachea https://www.therespiratorysystem.com/category/upper-respiratory-tract/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/12/Upper-Respiratory-Tract.jpgLabeled diagram of the upper respiratory tract: nasal cavity, paranasal sinuses, nostril, oral cavity, pharynx, larynx and vocal cordshttps://www.therespiratorysystem.com/wp-content/themes/Respiratory/images/respiratory-system-diagram.jpgLabeled diagram of the human respiratory system showing the nasal cavity, pharynx, larynx and trachea above the lungs 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how the soft palate and uvula rise to close off the nasopharynx during a swallowhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--uvula/uvula-tissues.webpLayer diagram of the uvula: mucous membrane, then glands and connective tissue, then the musculus uvulae at the corehttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--uvula/uvula-vs-epiglottis.webpComparison chart of the uvula and the epiglottis: location, tissue, shape, what each guards and their roles https://www.therespiratorysystem.com/vital-capacity/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/vital-capacity/hero.webpBar chart showing vital capacity as the sum of inspiratory reserve volume, tidal volume and expiratory reserve volume, without residual volumehttps://www.therespiratorysystem.com/assets/img/diagrams/vital-capacity/how-vital-capacity-is-measured.webpSix-step diagram of a vital capacity test: sit with nose clip, breathe normally, inhale fully, exhale completely, read volume, comparehttps://www.therespiratorysystem.com/assets/img/diagrams/vital-capacity/restrictive-vs-obstructive.webpComparison chart of how restrictive and obstructive lung conditions change vital capacity, total lung capacity, residual volume and FEV1/FVC https://www.therespiratorysystem.com/vocal-cords/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/vocal-cords/hero.webpComparison chart of the true vocal cords and the false vocal cords: position, color, core, lining, vibration and main jobshttps://www.therespiratorysystem.com/wp-content/uploads/2016/11/Larynx-Diagram.jpgSide view of the head and neck showing the vocal cord inside the larynx between the supraglottis and subglottis, above the tracheahttps://www.therespiratorysystem.com/assets/img/diagrams/vocal-cords/vocal-fold-layers.webpLayer diagram of a vocal fold from the epithelium through the three layers of lamina propria to the vocalis musclehttps://www.therespiratorysystem.com/assets/img/diagrams/vocal-cords/vocal-cord-positions.webpSix-step diagram of vocal cord positions during quiet breathing, deep breathing, speaking, whispering, swallowing and coughing https://www.therespiratorysystem.com/which-lung-is-bigger/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/which-lung-is-bigger/hero.webpSide-by-side chart comparing the right and left lung: size, width, length, lobes, fissures, segments and heart impressionhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Lungs.jpgLabeled front view of both lungs: the three-lobed right lung and the narrower two-lobed left lung with its cardiac notchhttps://www.therespiratorysystem.com/assets/img/diagrams/which-lung-is-bigger/why-the-right-lung-is-bigger.webpSix-step diagram explaining why the right lung is bigger: lung bud branching, heart position, cardiac notch, liver and the result for each lung https://www.therespiratorysystem.com/why-do-we-sneeze/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/why-do-we-sneeze/hero.webpSix-step diagram of the sneeze reflex from an irritant in the nose through the trigeminal nerve and brainstem to the blast of airhttps://www.therespiratorysystem.com/assets/img/diagrams/why-do-we-sneeze/sneeze-vs-cough.webpComparison chart of a sneeze and a cough: area cleared, trigger, sensory nerve, air route, voluntary control and eyes https://www.therespiratorysystem.com/adenoids/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/adenoids/hero.webpComparison chart of the adenoids and the palatine tonsils by name, number, location, visibility, lining, surface and what each sampleshttps://www.therespiratorysystem.com/assets/img/diagrams/adenoids/air-past-the-adenoids.webpStep diagram of inhaled air passing from the nostrils through the nasal cavity and choanae over the adenoids into the oropharynxhttps://www.therespiratorysystem.com/assets/img/diagrams/adenoids/adenoid-size-with-age.webpBar chart showing the relative size of the adenoids, small at birth, largest in early childhood and shrinking through adolescence into adulthood https://www.therespiratorysystem.com/breathing-patterns/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/breathing-patterns/hero.webpComparison chart of a normal breathing pattern (eupnea) and abnormal breathing patterns by rate, depth, rhythm and efforthttps://www.therespiratorysystem.com/assets/img/diagrams/breathing-patterns/resting-rates.webpBar chart comparing resting breathing rates in adult bradypnea, normal adults, adult tachypnea and newbornshttps://www.therespiratorysystem.com/assets/img/diagrams/breathing-patterns/cheyne-stokes-cycle.webpCycle diagram of Cheyne-Stokes breathing: breaths deepen, peak, fade, pause in apnea and restart as carbon dioxide builds https://www.therespiratorysystem.com/breathing-at-high-altitude/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/breathing-at-high-altitude/hero.webpSix-step diagram of breathing at high altitude: lower air pressure, lower oxygen pressure, carotid body response, faster breathing, alkalosishttps://www.therespiratorysystem.com/assets/img/diagrams/breathing-at-high-altitude/oxygen-pressure-by-altitude.webpBar chart showing the inspired partial pressure of oxygen falling from sea level to the summit of Mount Everesthttps://www.therespiratorysystem.com/assets/img/diagrams/breathing-at-high-altitude/arrival-vs-acclimatized.webpComparison chart of breathing, blood carbon dioxide, pH, heart rate, red blood cells and exercise on arrival at altitude and after acclimatization https://www.therespiratorysystem.com/breathing-vs-respiration/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/breathing-vs-respiration/hero.webpComparison chart of breathing and cellular respiration showing process type, location, energy, gases and controlhttps://www.therespiratorysystem.com/assets/img/diagrams/breathing-vs-respiration/breath-to-energy.webpSix-step diagram from breathing to external respiration, gas transport, internal respiration, cellular respiration and carbon dioxide removal https://www.therespiratorysystem.com/glossary/choanae/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2018/01/Choanae-Internal-Nares.jpgDiagram of the choanae (internal nares) at the back of the nasal cavity, opening into the nasopharynx on either side of the vomer https://www.therespiratorysystem.com/cough-reflex/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/cough-reflex/hero.webpSix-step diagram of the cough reflex pathway from airway receptors through the vagus nerve and medulla to the breathing muscleshttps://www.therespiratorysystem.com/assets/img/diagrams/cough-reflex/cough-stages-cycle.webpCycle diagram of the stages of a cough: inspiratory, compressive, expulsive and relaxationhttps://www.therespiratorysystem.com/assets/img/diagrams/cough-reflex/cough-vs-gag.webpComparison chart of the cough reflex and the gag reflex, showing their purpose, trigger sites, nerves and actions https://www.therespiratorysystem.com/respiratory-system-development/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-development/hero.webpFive-stage diagram of lung development: embryonic, pseudoglandular, canalicular, saccular and alveolar stages with typical weekshttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-development/airway-branching-development.webpBranching diagram of airway development from the lung bud through bronchial, lobar and segmental buds to terminal bronchioles and alveolihttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-development/fetal-vs-newborn-lungs.webpComparison chart of fetal lungs and lungs after birth: contents, site of gas exchange, blood flow, shunts, vessels and breathing https://www.therespiratorysystem.com/glossary/2026-11-02https://www.therespiratorysystem.com/wp-content/themes/Respiratory/images/respiratory-system-diagram.jpgLabeled diagram of the human respiratory system with the nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, lung lobes and diaphragmhttps://www.therespiratorysystem.com/wp-content/uploads/2017/11/Lung-Lobes.jpgDiagram of the lung lobes: superior, middle and inferior lobes of the right lung and superior and inferior lobes of the left lung https://www.therespiratorysystem.com/glossary/haldane-effect/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--haldane-effect/hero.webpDiagram of the Haldane effect in the lungs: oxygen enters a red blood cell and binds hemoglobin, which releases carbon dioxidehttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--haldane-effect/haldane-effect-steps.webpSix-step diagram of the Haldane effect in the lungs, from oxygen binding hemoglobin to carbon dioxide leaving the bloodhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--haldane-effect/haldane-vs-bohr.webpComparison chart of the Haldane effect and the Bohr effect: what each describes, its signal, curve and role in the lungs and tissues https://www.therespiratorysystem.com/glossary/hering-breuer-reflex/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--hering-breuer-reflex/hero.webpCycle diagram of the Hering-Breuer reflex: lung inflation, stretch receptors, vagus nerve, brainstem and exhalationhttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--hering-breuer-reflex/inflation-vs-deflation.webpComparison chart of the Hering-Breuer inflation reflex and deflation reflex: trigger, receptors, nerve and effecthttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--hering-breuer-reflex/infants-vs-adults.webpComparison chart of the Hering-Breuer reflex in newborns and adults: strength, when it acts and main role https://www.therespiratorysystem.com/how-do-lungs-work/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/how-do-lungs-work/hero.webpEight-step diagram of how the lungs work: brain signal, diaphragm contraction, air in, cleaning, oxygen in, carbon dioxide out, heart, breath outhttps://www.therespiratorysystem.com/wp-content/uploads/2017/09/Lungs.jpgLabeled diagram of the lungs showing the trachea, primary bronchi, lobes, alveoli, pleura and diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/how-do-lungs-work/lungs-and-heart-loop.webpCycle diagram of how the lungs work with the heart: right heart, lungs, left heart, body tissues and veins back to the right heart https://www.therespiratorysystem.com/exercise-and-the-respiratory-system/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/exercise-and-the-respiratory-system/hero.webpSix-step diagram of how breathing responds to exercise, from anticipation and a fast rise at onset to steady state and recoveryhttps://www.therespiratorysystem.com/assets/img/diagrams/exercise-and-the-respiratory-system/rest-vs-exercise.webpComparison chart of breathing at rest and during hard exercise, including breath size, air per minute, exhalation and lung capillarieshttps://www.therespiratorysystem.com/assets/img/diagrams/exercise-and-the-respiratory-system/ventilation-by-activity.webpBar diagram showing how the volume of air breathed per minute increases from rest to walking, jogging, hard running and maximal effort https://www.therespiratorysystem.com/how-long-can-you-hold-your-breath/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/how-long-can-you-hold-your-breath/hero.webpSix-step diagram of a breath hold: breath stops, oxygen falls, carbon dioxide builds up, chemoreceptors fire, diaphragm contractions, breaking pointhttps://www.therespiratorysystem.com/assets/img/diagrams/how-long-can-you-hold-your-breath/land-vs-water.webpComparison of a breath hold on land and in water: diving reflex, heart rate, blood flow, oxygen use and what happens after faintinghttps://www.therespiratorysystem.com/assets/img/diagrams/how-long-can-you-hold-your-breath/humans-vs-diving-mammals.webpBar chart comparing the longest breath holds of an untrained adult, a record freediver, a sperm whale and a Cuvier's beaked whale https://www.therespiratorysystem.com/respiratory-system-homeostasis/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-homeostasis/hero.webpNegative feedback loop of breathing: rising CO2, chemoreceptors, brainstem, diaphragm and intercostals, faster breathing, balance restoredhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-homeostasis/too-slow-vs-too-fast.webpComparison of breathing too slowly and too fast: effect on blood carbon dioxide, pH, acid-base result, brainstem and kidney response https://www.therespiratorysystem.com/respiratory-system-and-other-body-systems/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-and-other-body-systems/hero.webpCycle diagram of how the muscular, nervous, respiratory and circulatory systems work together to control breathinghttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-and-other-body-systems/exercise-teamwork.webpFive-step diagram of how the muscular, nervous, respiratory and circulatory systems respond together during exercisehttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-system-and-other-body-systems/respiratory-vs-digestive.webpComparison chart of the respiratory system and the digestive system: jobs, shared pharynx, main tubes, organs and wastes https://www.therespiratorysystem.com/how-to-make-a-lung-model/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/how-to-make-a-lung-model/hero.webpSix-step diagram of how to make a balloon lung model from a plastic bottle, small balloons, a Y-shaped straw, clay and a balloon diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/how-to-make-a-lung-model/model-vs-body.webpChart matching each part of the balloon lung model to the body: bottle and chest wall, straw and trachea, balloons and lungs, sheet and diaphragmhttps://www.therespiratorysystem.com/assets/img/diagrams/how-to-make-a-lung-model/how-the-model-breathes.webpCycle diagram of the balloon lung model: pulling the sheet lowers pressure and inflates the balloons, releasing it deflates them https://www.therespiratorysystem.com/hyperventilation-and-hypoventilation/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/hyperventilation-and-hypoventilation/hero.webpComparison chart of hyperventilation and hypoventilation showing their effects on blood CO2, pH, oxygen and capnographyhttps://www.therespiratorysystem.com/assets/img/diagrams/hyperventilation-and-hypoventilation/co2-levels.webpBar chart comparing arterial carbon dioxide levels in hypoventilation, normal breathing and hyperventilationhttps://www.therespiratorysystem.com/assets/img/diagrams/hyperventilation-and-hypoventilation/co2-feedback-loop.webpCycle diagram of the carbon dioxide feedback loop that adjusts breathing through chemoreceptors and the brainstem https://www.therespiratorysystem.com/inferior-nasal-concha/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/04/Inferior-Nasal-Concha.jpgFront view of the skull labeling the inferior nasal concha in the lower nasal opening beside the vomer, with nearby skull bones https://www.therespiratorysystem.com/glossary/intercostal-muscles/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2018/05/Intercostal-Muscles.jpgFront view of the rib cage showing the intercostal muscles between the ribs, with a close-up of the external, internal and innermost layershttps://www.therespiratorysystem.com/wp-content/uploads/2018/05/Intercostal-Muscles-Function.jpgRib cage during inhalation and exhalation: external intercostals lift the ribs as the diaphragm contracts, internal intercostals lower them https://www.therespiratorysystem.com/glossary/lung-lobes/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2017/11/Lung-Lobes.jpgLabeled diagram of the lung lobes: right lung with superior, middle and inferior lobes, left lung with two lobes, fissures and cardiac notch https://www.therespiratorysystem.com/middle-nasal-concha/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/04/Middle-Nasal-Concha.jpgFront view of the skull labeling the middle nasal concha of the ethmoid bone between the superior and inferior nasal conchae https://www.therespiratorysystem.com/nasal-conchae-nasal-turbinates/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/04/Nasal-Conchae.jpgLabeled side view of the nasal cavity and front view of the skull showing the superior, middle and inferior nasal conchaehttps://www.therespiratorysystem.com/wp-content/uploads/2015/04/Nasal-Turbinates.jpgCoronal section of the nose showing the superior, middle and inferior turbinates, the meatuses below them, the septum and sinuses https://www.therespiratorysystem.com/nasal-meatus/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/04/Nasal-Meatus-Anatomy.jpgFront cross-section of the nose labeling the superior, middle and inferior meatuses beneath the matching nasal conchae on both sideshttps://www.therespiratorysystem.com/wp-content/uploads/2015/04/Nasal-Meatus.jpgSide view of the lateral nasal wall showing the meatuses with the sinus openings, semilunar hiatus and nasolacrimal duct opening labeled https://www.therespiratorysystem.com/glossary/nasal-vestibule/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/glossary--nasal-vestibule/hero.webpFive-step diagram of air entering the nose: nostril, nasal vestibule, limen nasi, internal nasal valve and nasal cavity properhttps://www.therespiratorysystem.com/wp-content/uploads/2018/01/Nostrils-Anatomy.jpgSide and underside views of the nose showing the nostrils and the lateral and medial crura of the major alar cartilagehttps://www.therespiratorysystem.com/assets/img/diagrams/glossary--nasal-vestibule/vestibule-vs-respiratory-region.webpComparison chart of the nasal vestibule and the respiratory region of the nasal cavity: lining, hairs, glands and function https://www.therespiratorysystem.com/glossary/nasopharynx/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2018/02/Nasopharynx.jpgSide view of the head showing the nasopharynx behind the nasal cavity, with the adenoids, Eustachian tube opening and soft palate https://www.therespiratorysystem.com/nose-vs-mouth-breathing/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/nose-vs-mouth-breathing/hero.webpComparison chart of nose breathing vs mouth breathing: filtering, warming, humidifying, resistance, nitric oxide, smell and best usehttps://www.therespiratorysystem.com/assets/img/diagrams/nose-vs-mouth-breathing/how-the-nose-conditions-air.webpSix-step diagram of how the nose filters, warms and humidifies air from the nostrils to the nasopharynxhttps://www.therespiratorysystem.com/wp-content/uploads/2015/12/Upper-Respiratory-Tract.jpgSide view of the head showing the nasal cavity and oral cavity both opening into the pharynx above the larynx and trachea https://www.therespiratorysystem.com/glossary/nostrils/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2018/01/Nostrils-Anatomy.jpgLabeled diagram of the nostrils (external nares) on the underside of the nose, with the ala, columella and nasal septum https://www.therespiratorysystem.com/glossary/oral-cavity/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2018/04/Oral-Cavity.jpgFront view of the open mouth labeling the lips, gums, teeth, hard and soft palate, uvula, tongue, frenula and submandibular duct openinghttps://www.therespiratorysystem.com/wp-content/uploads/2018/04/Oral-Cavity-Anatomy-Diagram.jpgSide view of the head showing the oral vestibule, oral cavity proper, hard and soft palate, uvula, tongue and oropharynx below the nasal cavity https://www.therespiratorysystem.com/partial-pressure-of-gases/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/partial-pressure-of-gases/hero.webpSix-step diagram of the oxygen cascade: PO2 falls from about 160 mmHg in air to 150, 100, 95 to 100, 40 and a few mmHg in cellshttps://www.therespiratorysystem.com/assets/img/diagrams/partial-pressure-of-gases/dalton-air-partial-pressures.webpBar chart of partial pressures in dry air at sea level: nitrogen largest, oxygen about a fifth, argon small, carbon dioxide a tracehttps://www.therespiratorysystem.com/assets/img/diagrams/partial-pressure-of-gases/pao2-vs-sao2.webpComparison chart of partial pressure of oxygen (PaO2) and oxygen saturation: what each measures, units, normal values and how they relate https://www.therespiratorysystem.com/pleural-cavity/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/pleural-cavity/hero.webpCycle diagram of pleural fluid turnover: filtration from parietal pleura capillaries, a thin film, downward flow, stomata and lymphatic drainagehttps://www.therespiratorysystem.com/assets/img/diagrams/pleural-cavity/pressure-during-a-breath.webpSix-step diagram of how pressure in the pleural cavity changes during one quiet breath in and outhttps://www.therespiratorysystem.com/assets/img/diagrams/pleural-cavity/pleura-vs-pleural-cavity.webpComparison chart of the pleura, the membrane around the lung, and the pleural cavity, the fluid-filled space between its layers https://www.therespiratorysystem.com/respiratory-rate/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/respiratory-rate/hero.webpCycle diagram of breathing rate control: brainstem rhythm, nerves, breathing muscles, blood gas change and chemoreceptor feedbackhttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-rate/breathing-rate-by-age.webpBar chart showing typical resting breathing rate highest in newborns and falling steadily through childhood to the adult rangehttps://www.therespiratorysystem.com/assets/img/diagrams/respiratory-rate/respiratory-rate-vs-heart-rate.webpComparison chart of respiratory rate and heart rate: what each counts, typical adult values, pacemaker, muscle and control https://www.therespiratorysystem.com/spirometry/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/spirometry/hero.webpSix-step diagram of a spirometry test, from sealing the mouthpiece to the forced breath out that gives FEV1 and FVChttps://www.therespiratorysystem.com/assets/img/diagrams/spirometry/spirogram-volumes.webpBar diagram comparing tidal volume, inspiratory and expiratory reserve volumes, vital capacity and residual volumehttps://www.therespiratorysystem.com/assets/img/diagrams/spirometry/obstructive-vs-restrictive.webpComparison chart of obstructive and restrictive spirometry patterns, showing FEV1, FVC, FEV1/FVC ratio and curve shapes https://www.therespiratorysystem.com/superior-nasal-concha/2026-11-02https://www.therespiratorysystem.com/wp-content/uploads/2015/04/Superior-Nasal-Concha.jpgFront view of the skull labeling the superior nasal concha high in the nasal cavity, with the middle and inferior conchae below https://www.therespiratorysystem.com/tonsils/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/tonsils/hero.webpRing diagram of Waldeyer's ring showing the pharyngeal, tubal, palatine and lingual tonsils arranged around the upper throathttps://www.therespiratorysystem.com/assets/img/diagrams/tonsils/palatine-tonsil-layers.webpLayer diagram of a palatine tonsil from the surface epithelium and crypts through lymphoid follicles to the fibrous capsulehttps://www.therespiratorysystem.com/assets/img/diagrams/tonsils/how-tonsils-respond.webpSix-step diagram of a tonsil immune response, from a germ trapped in a crypt to antibody release and memory cells https://www.therespiratorysystem.com/ventilation-perfusion-ratio/2026-11-02https://www.therespiratorysystem.com/assets/img/diagrams/ventilation-perfusion-ratio/hero.webpComparison diagram of low and high ventilation-perfusion ratios, from shunt to dead space, with their effects on alveolar oxygen and carbon dioxidehttps://www.therespiratorysystem.com/assets/img/diagrams/ventilation-perfusion-ratio/v-q-apex-to-base.webpBar diagram showing the ventilation-perfusion ratio falling from the apex to the base of an upright 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