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PowerPoint® Lecture Slides prepared by Leslie Hendon University of Alabama, Birmingham CHAPTER 22 The Respiratory System • Basic functions of the respiratory system • Supplies body with oxygen • Disposes of carbon dioxide • Four processes involved in respiration Part 1 • • • • The Respiratory System Copyright © 2011 Pearson Education, Inc. Functional Anatomy of the Respiratory System Pulmonary ventilation External respiration Transport of respiratory gases Internal respiration Copyright © 2011 Pearson Education, Inc. Organs of the Respiratory System • Respiratory organs • • • • Nasal cavity Nose, nasal cavity, and paranasal sinuses Pharynx, larynx, and trachea Bronchi and smaller branches Lungs and alveoli Nostril Larynx Oral cavity Pharynx Left main (primary) bronchus Trachea Carina of trachea Right main (primary) bronchus Right lung Parietal pleura Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. Organs of the Respiratory System The Nose • Divided into • • • • • • Conducting zone • Respiratory zone Copyright © 2011 Pearson Education, Inc. Bronchi Alveoli Left lung Diaphragm Figure 22.1 Provides an airway for respiration Moistens and warms air Filters inhaled air Resonating chamber for speech Houses olfactory receptors Copyright © 2011 Pearson Education, Inc. 1 The Nose The Nasal Cavity • Size variation due to differences in nasal cartilages • Skin is thin—contains many sebaceous glands Frontal bone Epicranius, frontal belly Root and bridge of nose Dorsum nasi Ala of nose Apex of nose Naris (nostril) Philtrum (a) Surface anatomy • External nares—nostrils • Divided by nasal septum • Continuous with nasopharynx • Posterior nasal apertures—choanae Nasal bone Septal cartilage Maxillary bone (frontal process) Lateral process of septal cartilage Minor alar cartilages Dense fibrous connective tissue Major alar cartilages (b) External skeletal framework Copyright © 2011 Pearson Education, Inc. Figure 22.2 Nasal Cavity • Two types of mucous membrane • Olfactory mucosa • Near roof of nasal cavity • Houses olfactory (smell) receptors • Respiratory mucosa • Lines nasal cavity • Epithelium is pseudostratified ciliated columnar Copyright © 2011 Pearson Education, Inc. The Upper Respiratory Tract Cribriform plate of ethmoid bone Sphenoid sinus Posterior nasal aperture Nasopharynx Pharyngeal tonsil Opening of pharyngotympanic tube Uvula Oropharynx Palatine tonsil Isthmus of the fauces Laryngopharynx Esophagus Trachea (c) Illustration Copyright © 2011 Pearson Education, Inc. Frontal sinus Nasal cavity Nasal conchae (superior, middle and inferior) Nasal meatuses (superior, middle, and inferior) Nasal vestibule Nostril Hard palate Soft palate Tongue Larynx Lingual tonsil Hyoid bone Epiglottis Vestibular fold Thyroid cartilage Vocal fold Cricoid cartilage Thyroid gland Copyright © 2011 Pearson Education, Inc. Respiratory Mucosa Nasal Conchae • Consists of • Superior and middle nasal conchae • Pseudostratified ciliated columnar epithelium • Goblet cells within epithelium • Underlying layer of lamina propria • Cilia move contaminated mucus posteriorly Figure 22.3c • Part of the ethmoid bone • Inferior nasal conchae • Separate bone • Project medially from the lateral wall of the nasal cavity • Particulate matter • Deflected to mucus-coated surfaces Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. 2 The Pharynx • Funnel-shaped passageway • Connects nasal cavity and mouth • Divided into three sections by location • Nasopharynx • Oropharynx • Laryngopharynx • Type of mucosal lining changes along its length The Nasopharynx • • • • Superior to the point where food enters Only an air passageway Closed off during swallowing Pharyngeal tonsil (adenoids) • Located on posterior wall • Destroys entering pathogens • Contains the opening to the pharyngotympanic tube (auditory tube) • Tubal tonsil • Provides some protection from infection Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. The Oropharynx The Laryngopharynx • Arch-like entranceway—fauces • Passageway for both food and air • Epithelium • Extends from soft palate to the epiglottis • Epithelium • Stratified squamous epithelium • Stratified squamous epithelium • Continuous with the esophagus and larynx • Two types of tonsils in the oropharynx • Palatine tonsils—in the lateral walls of the fauces • Lingual tonsils—covers the posterior surface of the tongue Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. The Larynx Nine Cartilages of the Larynx • Three functions • Thyroid cartilage • Voice production • Provides an open airway • Routes air and food into the proper channels • Superior opening is • Closed during swallowing • Open during breathing • Shield-shaped, forms laryngeal prominence (Adam’s apple) • Three pairs of small cartilages • Arytenoid cartilages • Corniculate cartilages • Cuneiform cartilages • Epiglottis • Tips inferiorly during swallowing Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. 3 The Larynx Anatomy of the Larynx Body of hyoid bone • Vocal ligaments of the larynx • Vocal folds (true vocal cords) • Act in sound production • Vestibular folds (false vocal cords) • No role in sound production Laryngeal prominence (Adam’s apple) Cricoid cartilage Sternal head Clavicular head Sternocleidomastoid Clavicle Jugular notch (a) Surface view • Epithelium of the larynx Epiglottis Thyrohyoid membrane Body of hyoid bone • Stratified squamous—superior portion • Pseudostratified ciliated columnar—inferior portion Thyroid cartilage Laryngeal prominence (Adam’s apple) Cricothyroid ligament Cricoid cartilage Cricotracheal ligament Tracheal cartilages (b) Anterior view Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. Anatomy of the Larynx Movements of the Vocal Folds Anterior Epiglottis Thyrohyoid membrane Hyoid bone Thyroid cartilage Cricoid cartilage Vocal ligaments of vocal cords Glottis Corniculate cartilage Arytenoid cartilage Thyroid cartilage Lateral cricoarytenoid muscle Arytenoid cartilage Cricoid cartilage Glottis Corniculate cartilage Posterior cricoarytenoid muscle Tracheal cartilages Posterior (c) Photograph of cartilaginous framework of the larynx, posterior view Base of tongue Epiglottis Thyrohyoid membrane Cuneiform cartilage Corniculate cartilage Arytenoid cartilage Arytenoid muscle Cricoid cartilage Figure 22.5a, b Body of hyoid bone Epiglottis Thyrohyoid membrane Vestibular fold (false vocal cord) Vocal fold (true vocal cord) Glottis Fatty pad Vestibular fold (false vocal cord) Thyroid cartilage Vocal fold (true vocal cord) Cricothyroid ligament Cricotracheal ligament Inner lining of trachea Cuneiform cartilage Tracheal cartilages (d) Sagittal section (anterior on the right) Copyright © 2011 Pearson Education, Inc. Corniculate cartilage (a) Vocal folds in closed position; closed glottis Figure 22.5c, d (b) Vocal folds in open position; open glottis Copyright © 2011 Pearson Education, Inc. The Larynx The Trachea • Voice production • Descends into the mediastinum • C-shaped cartilage rings keep airway open • Carina • Length of the vocal folds changes with pitch • Loudness depends on the force of air across the vocal folds • Sphincter function of the larynx • Valsalva’s maneuver—straining • Innervation of the larynx Figure 22.6 • Marks where trachea divides into two primary bronchi • Epithelium • Pseudostratified ciliated columnar • Recurrent laryngeal nerves (branch of vagus) Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. 4 The Trachea Bronchi in the Conducting Zone Mucosa Pseudostratified ciliated columnar epithelium Lamina propria (connective tissue) • Bronchial tree Submucosa Seromucous gland in submucosa Posterior Hyaline cartilage Mucosa Esophagus (b) Photomicrograph of the tracheal wall (250×) Submucosa Trachealis muscle Lumen of trachea Seromucous gland in submucosa Hyaline cartilage Adventitia Anterior (a) Cross section of the trachea and esophagus Figure 22.7 Copyright © 2011 Pearson Education, Inc. Bronchi in the Conducting Zone Superior lobe of right lung • Extensively branching respiratory passageways • Primary bronchi (main bronchi) • Largest bronchi • Right main bronchi • Wider and shorter than the left Copyright © 2011 Pearson Education, Inc. Bronchi in the Conducting Zone Trachea Mucosa Pseudostratified epithelium Lamina propria Superior lobe of left lung Left main (primary) bronchus Lobar (secondary) bronchus Segmental (tertiary) bronchus Inferior lobe of left lung Lumen Cartilage plate Smooth muscle Middle lobe Inferior lobe of right lung of right lung (a) The branching of the bronchial tree Copyright © 2011 Pearson Education, Inc. Fibromusculocartilaginous layer (b) Photomicrograph of a bronchus (13×) Figure 22.8a Copyright © 2011 Pearson Education, Inc. Bronchi in the Conducting Zone Changes in Tissue Composition along Conducting Pathways • Secondary (lobar) bronchi • Supportive connective tissues change • Three on the right • Two on the left • Tertiary (segmental) bronchi • Branch into each lung segment • Bronchioles • Little bronchi, less than 1 mm in diameter • Terminal bronchioles • Less than 0.5 mm in diameter Copyright © 2011 Pearson Education, Inc. Figure 22.8b • C-shaped rings replaced by cartilage plates • Epithelium changes • First, pseudostratified ciliated columnar • Replaced by simple columnar, then simple cuboidal epithelium • Smooth muscle becomes important • Airways widen with sympathetic stimulation • Airways constrict under parasympathetic direction Copyright © 2011 Pearson Education, Inc. 5 Structures of the Respiratory Zone Structures of the Respiratory Zone • Consists of air-exchanging structures • Respiratory bronchioles—branch from terminal bronchioles Alveoli Alveolar duct • Lead to alveolar ducts • Lead to alveolar sacs Respiratory bronchioles Terminal bronchiole Alveolar duct Alveolar sac (a) Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. Structures of the Respiratory Zone Figure 22.9a Structures of the Respiratory Zone • Alveoli Respiratory bronchiole Alveolar pores Alveolar duct • ~300 million alveoli account for tremendous surface area of the lungs • Surface area of alveoli is ˜140 square meters Alveoli Alveolar sac (b) Copyright © 2011 Pearson Education, Inc. Figure 22.9b Copyright © 2011 Pearson Education, Inc. Structures of the Respiratory Zone Structures of the Respiratory Zone • Structure of alveoli • Structures of alveoli (continued) • Type I cells—single layer of simple squamous epithelial cells • Surrounded by basal lamina • Alveolar and capillary walls plus their basal lamina form the ... • Respiratory membrane Copyright © 2011 Pearson Education, Inc. • Type II cells—scattered among type I cells • Are cuboidal epithelial cells • Secrete surfactant • Reduces surface tension within alveoli– keeps alveoli from collapsing when we exhale • Alveolar macrophages Copyright © 2011 Pearson Education, Inc. 6 Anatomy of Alveoli and the Respiratory Membrane Anatomy of Alveoli and the Respiratory Membrane Red blood cell Nucleus of type I (squamous epithelial) cell Alveolar pores Terminal bronchiole Respiratory bronchiole Capillary O2 Smooth muscle Capillary CO2 Alveolus Macrophage Endothelial cell nucleus Elastic fibers Alveolus Alveolus Respiratory membrane Capillaries (a) Diagrammatic view of capillary-alveoli relationships Red blood cell Type I cell in capillary of alveolar wall Alveoli (gas-filled Type II (surfactantair spaces) secreting) cell Alveolar epithelium Fused basement membranes of the alveolar epithelium and the capillary endothelium Capillary endothelium (c) Detailed anatomy of the respiratory membrane Figure 22.10a, b Copyright © 2011 Pearson Education, Inc. Figure 22.10c Copyright © 2011 Pearson Education, Inc. The Respiratory Zone Gross Anatomy of the Lungs • Features of alveoli • Major landmarks of the lungs • Surrounded by elastic fibers • Interconnect by way of alveolar pores • Internal surfaces • A site for free movement of alveolar macrophages • Apex, base, hilum, and root • Left lung • Superior and inferior lobes • Fissure—oblique • Right lung • Superior, middle, and inferior lobes • Fissures—oblique and horizontal Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. Gross Anatomy of the Lungs Bronchopulmonary Segments Right lung Anterior View of Thoracic Structures Right superior lobe (3 segments) Left lung Left superior lobe (4 segments) Intercostal muscle Rib Parietal pleura Pleural cavity Visceral pleura Lung Apex of lung Right superior lobe Horizontal fissure Right middle lobe Oblique fissure Left superior lobe Oblique fissure Left inferior lobe Right inferior lobe Heart (in mediastinum) Diaphragm Cardiac notch Base of lung (a) Anterior view. The lungs flank mediastinal structures laterally. Copyright © 2011 Pearson Education, Inc. Apex of lung Pulmonary artery Trachea Thymus Left superior lobe Left main bronchus Oblique fissure Pulmonary vein Impression of heart Oblique fissure Left inferior lobe Hilum Aortic impression Lobules (b) Photograph of medial view of the left lung Figure 22.11a, b Right middle lobe (2 segments) Right inferior lobe (5 segments) Copyright © 2011 Pearson Education, Inc. Left inferior lobe (5 segments) Figure 22.12 7 Blood Supply and Innervation of the Lungs Transverse Cut through the Superior Thorax • Pulmonary arteries • Deliver oxygen-poor blood to the lungs • Pulmonary veins Vertebra • Carry oxygenated blood to the heart • Bronchial arteries (2 on left, 1 on right) • Supply systemic (oxygenated) blood to the lung structures (enter lung’s medial surface along with the large pulmonary vessels) Posterior Esophagus (in mediastinum) Root of lung at hilum Left main bronchus Left pulmonary artery Left pulmonary vein Right lung Parietal pleura Visceral pleura Left lung Pleural cavity • Innervation Thoracic wall • Sympathetic, parasympathetic, and visceral sensory fibers • Parasympathetic—constrict airways • Sympathetic—dilate airways Copyright © 2011 Pearson Education, Inc. The Pleurae Pulmonary trunk Pericardial membranes Heart (in mediastinum) Anterior mediastinum Sternum Anterior (d) Transverse section through the thorax, viewed from above. Lungs, pleural membranes, and major organs in the mediastinum are shown. Figure 22.11d Copyright © 2011 Pearson Education, Inc. Diagram of the Pleurae and Pleural Cavities Intercostal muscle • A double-layered sac surrounding each lung Rib • Parietal pleura • Visceral pleura Parietal pleura Pleural cavity Visceral pleura Lung Trachea Thymus • Pleural cavity Apex of lung • Potential space between the visceral and parietal pleurae Right superior lobe • Pleurae help divide the thoracic cavity Horizontal fissure Right middle lobe • Central mediastinum • Two lateral pleural compartments Oblique fissure Left superior lobe Oblique fissure Left inferior lobe Right inferior lobe Heart (in mediastinum) Diaphragm Cardiac notch Base of lung (a) Anterior view. The lungs flank mediastinal structures laterally. Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. Location of Lungs in Thoracic Cavity Figure 22.11a The Mechanisms of Ventilation • Two phases of pulmonary ventilation • Inspiration—inhalation • Expiration—exhalation Clavicle Lung Rib 3 4 Rib 8 5 Nipple 9 6 Lung 7 10 11 12 Parietal pleura 8 Midaxillary line 9 10 Midclavicular line (a) Posterior view Copyright © 2011 Pearson Education, Inc. (b) Anterior view Infrasternal angle at the xiphisternal joint Costal margin Parietal pleura Figure 22.13 Copyright © 2011 Pearson Education, Inc. 8 Inspiration Inspiration • Volume of thoracic cavity increases • Deep inspiration requires • Decreases internal gas pressure • Action of the diaphragm • Diaphragm flattens • Action of intercostal muscles • Contraction raises the ribs • • • • Copyright © 2011 Pearson Education, Inc. Scalenes Sternocleidomastoid Pectoralis minor Erector spinae—extends the back Copyright © 2011 Pearson Education, Inc. Expiration Changes in Thoracic Volume (a) Inspiration Diaphragm and intercostal muscles contract (diaphragm descends and rib cage rises). Thoracic cavity volume increases. • Quiet expiration—chiefly a passive process • Inspiratory muscles relax • Diaphragm moves superiorly • Volume of thoracic cavity decreases Changes in superiorinferior and anteriorposterior dimensions • Forced expiration—an active process • Produced by contraction of • Internal and external oblique muscles • Transverse abdominis muscles Changes in lateral dimensions (superior view) External intercostals contract. Ribs and sternum are depressed as external intercostals relax. Diaphragm moves superiorly as it relaxes. External intercostals relax. Copyright © 2011 Pearson Education, Inc. Changes in Thoracic Volume Trachea Main bronchi 2 Inspiration: Inspiratory muscles contract and increase the volume of the thoracic and pleural cavities. Pleural fluid in the pleural cavity holds the parietal and visceral pleura close together, causing the lungs to expand. As volume increases, pressure decreases and air flows into the lungs. 3 Expiration: Inspiratory muscles relax, reducing thoracic volume, and the lungs recoil. Simultaneously, volumes of the pleural cavity and the lungs decrease, causing pressure to increase in the lungs, and air flows out. Resting state is reestablished. Copyright © 2011 Pearson Education, Inc. Ribs are elevated and sternum flares as external intercostals contract. Diaphragm moves inferiorly during contraction. Copyright © 2011 Pearson Education, Inc. 1 At rest, no air movement: Air pressure in lungs is equal to atmospheric (air) pressure. Pressure in the pleural cavity is less than pressure in the lungs. This pressure difference keeps the lungs inflated. (b) Expiration Inspiratory muscles relax (diaphragm rises and rib cage descends due to recoil of the costal cartilages). Thoracic cavity volume decreases. Neural Control of Ventilation Thoracic wall Pleural cavity Lung Figure 22.14 Visceral pleura Lung Parietal pleura • Most important respiratory center Pleural Thoracic cavity wall • VRG—ventral respiratory group • Located in reticular formation in the medulla oblongata • Neurons generate respiratory rhythm Diaphragm Air At rest V P Expanded V P Air Air flows in V P Air flows out V P Figure 22.15 Copyright © 2011 Pearson Education, Inc. 9 Respiratory Centers in the Brain Stem Neural Control of Ventilation • Respiratory center Pons Medulla Pontine respiratory centers interact with the medullary respiratory centers to smooth the respiratory pattern. Ventral respiratory group (VRG) contains rhythm generators whose output drives respiration. Pons Medulla To inspiratory muscles Dorsal respiratory group (DRG) integrates peripheral sensory input and modifies the rhythms generated by the VRG. • Generates baseline respiration rate • In the reticular formation of the medulla oblongata • Chemoreceptors • Sensitive to rising and falling oxygen levels • Central chemoreceptors—located in medulla • Peripheral chemoreceptors • Aortic bodies • Carotid bodies Diaphragm External intercostal muscles Figure 22.16 Copyright © 2011 Pearson Education, Inc. Location of Peripheral Chemoreceptors Copyright © 2011 Pearson Education, Inc. Disorders of Lower Respiratory Structures • Bronchial asthma Brain • A type of allergic inflammation • Hypersensitivity to irritants in the air or to stress • Asthma attacks characterized by • Contraction of bronchiole smooth muscle • Secretion of mucus in airways Sensory nerve fiber in cranial nerve IX (pharyngeal branch of glossopharyngeal) External carotid artery Internal carotid artery Carotid body Common carotid artery Cranial nerve X (vagus nerve) Sensory nerve fiber in cranial nerve X Aortic bodies in aortic arch Aorta Heart Copyright © 2011 Pearson Education, Inc. Figure 22.17 Copyright © 2011 Pearson Education, Inc. Disorders of Lower Respiratory Structures Disorders of Lower Respiratory Structures • Cystic fibrosis (CF)—inherited disease • Chronic obstructive pulmonary disease (COPD) • Exocrine gland function is disrupted • Respiratory system affected by • Oversecretion of viscous mucus Copyright © 2011 Pearson Education, Inc. • Airflow into and out of the lungs is difficult • Obstructive emphysema • Chronic bronchitis • History of smoking Copyright © 2011 Pearson Education, Inc. 10 Disorders of Lower Respiratory Structures Figure 22.18 Copyright © 2011 Pearson Education, Inc. Disorders of Upper Respiratory Structures Alveolar Changes in Emphysema Copyright © 2011 Pearson Education, Inc. Figure 22.19 The Respiratory System Throughout Life • By week 4 of development • Epistaxis—nosebleed • Olfactory placodes appear • Invaginate to form olfactory pits • Laryngotracheal bud • Forms trachea, bronchi, and bronchi subdivisions • Reaches functional maturity late in development • At birth, only one-sixth of alveoli are present • Those who begin smoking as teenagers • Lungs never fully develop • Additional alveoli never form Copyright © 2011 Pearson Education, Inc. Copyright © 2011 Pearson Education, Inc. The Respiratory System Throughout Life Aging of the Respiratory System Future mouth Pharynx Frontonasal elevation Eye Olfactory placode Foregut Stomodeum (future mouth) Olfactory placode Esophagus Liver (a) 4 weeks: anterior superficial view of the embryo’s head Trachea Laryngotracheal Bronchial bud buds (b) 5 weeks: left lateral view of the developing lower respiratory passageway mucosae Copyright © 2011 Pearson Education, Inc. Figure 22.20 • Number of glands in the nasal mucosa declines • Nose dries • Produces thickened mucus • Thoracic wall becomes more rigid • Lungs lose elasticity • Oxygen levels in the blood may fall Copyright © 2011 Pearson Education, Inc. 11
