Transcript full_resp
PowerPoint® Lecture Slides prepared by Leslie Hendon University of Alabama, Birmingham CHAPTER 22 Part 1 The Respiratory System Copyright © 2011 Pearson Education, Inc. The Respiratory System • Basic functions of the respiratory system • Supplies body with oxygen • Disposes of carbon dioxide • Four processes involved in respiration • • • • Pulmonary ventilation External respiration Transport of respiratory gases Internal respiration Copyright © 2011 Pearson Education, Inc. Functional Anatomy of the Respiratory System • Respiratory organs • • • • Nose, nasal cavity, and paranasal sinuses Pharynx, larynx, and trachea Bronchi and smaller branches Lungs and alveoli Copyright © 2011 Pearson Education, Inc. Organs of the Respiratory System Nasal cavity Nostril Larynx Trachea Carina of trachea Right main (primary) bronchus Right lung Parietal pleura Copyright © 2011 Pearson Education, Inc. Oral cavity Pharynx Left main (primary) bronchus Bronchi Alveoli Left lung Diaphragm Figure 22.1 Organs of the Respiratory System • Divided into • Conducting zone • Respiratory zone Copyright © 2011 Pearson Education, Inc. The Nose • • • • • Provides an airway for respiration Moistens and warms air Filters inhaled air Resonating chamber for speech Houses olfactory receptors Copyright © 2011 Pearson Education, Inc. The Nose • 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 Copyright © 2011 Pearson Education, Inc. 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 Figure 22.2 The Nasal Cavity • External nares—nostrils • Divided by nasal septum • Continuous with nasopharynx • Posterior nasal apertures—choanae Copyright © 2011 Pearson Education, Inc. 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 Figure 22.3c Respiratory Mucosa • Consists of • Pseudostratified ciliated columnar epithelium • Goblet cells within epithelium • Underlying layer of lamina propria • Cilia move contaminated mucus posteriorly Copyright © 2011 Pearson Education, Inc. Nasal Conchae • Superior and middle nasal conchae • 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. 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 Copyright © 2011 Pearson Education, Inc. 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. The Oropharynx • Arch-like entranceway—fauces • Extends from soft palate to the epiglottis • Epithelium • Stratified squamous epithelium • 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. The Laryngopharynx • Passageway for both food and air • Epithelium • Stratified squamous epithelium • Continuous with the esophagus and larynx Copyright © 2011 Pearson Education, Inc. The Larynx • Three functions • Voice production • Provides an open airway • Routes air and food into the proper channels • Superior opening is • Closed during swallowing • Open during breathing Copyright © 2011 Pearson Education, Inc. Nine Cartilages of the Larynx • Thyroid cartilage • 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. The Larynx • Vocal ligaments of the larynx • Vocal folds (true vocal cords) • Act in sound production • Vestibular folds (false vocal cords) • No role in sound production • Epithelium of the larynx • Stratified squamous—superior portion • Pseudostratified ciliated columnar—inferior portion Copyright © 2011 Pearson Education, Inc. Anatomy of the Larynx Body of hyoid bone Laryngeal prominence (Adam’s apple) Cricoid cartilage Sternal head Clavicular head Sternocleidomastoid Clavicle Jugular notch (a) Surface view Epiglottis Thyrohyoid membrane Body of hyoid bone Thyroid cartilage Laryngeal prominence (Adam’s apple) Cricothyroid ligament Cricoid cartilage Cricotracheal ligament Tracheal cartilages (b) Anterior view Copyright © 2011 Pearson Education, Inc. Figure 22.5a, b Anatomy of the Larynx Epiglottis Thyrohyoid membrane Hyoid bone Corniculate cartilage Arytenoid cartilage Thyroid cartilage Cricoid cartilage Glottis Tracheal cartilages (c) Photograph of cartilaginous framework of the larynx, posterior view Epiglottis Thyrohyoid membrane Body of hyoid bone Thyrohyoid membrane Cuneiform cartilage Corniculate cartilage Arytenoid cartilage Arytenoid muscle Cricoid cartilage Fatty pad Vestibular fold (false vocal cord) Thyroid cartilage Vocal fold (true vocal cord) Cricothyroid ligament Cricotracheal ligament Tracheal cartilages (d) Sagittal section (anterior on the right) Copyright © 2011 Pearson Education, Inc. Figure 22.5c, d Movements of the Vocal Folds Anterior Thyroid cartilage Cricoid cartilage Vocal ligaments of vocal cords Glottis Lateral cricoarytenoid muscle Arytenoid cartilage Corniculate cartilage Posterior cricoarytenoid muscle Posterior Base of tongue Epiglottis Vestibular fold (false vocal cord) Vocal fold (true vocal cord) Glottis Inner lining of trachea Cuneiform cartilage Corniculate cartilage (a) Vocal folds in closed position; closed glottis Copyright © 2011 Pearson Education, Inc. (b) Vocal folds in open position; open glottis Figure 22.6 The Larynx • Voice production • 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 • Recurrent laryngeal nerves (branch of vagus) Copyright © 2011 Pearson Education, Inc. The Trachea • Descends into the mediastinum • C-shaped cartilage rings keep airway open • Carina • Marks where trachea divides into two primary bronchi • Epithelium • Pseudostratified ciliated columnar Copyright © 2011 Pearson Education, Inc. The Trachea Mucosa Pseudostratified ciliated columnar epithelium Lamina propria (connective tissue) Submucosa Seromucous gland in submucosa Posterior Hyaline cartilage Mucosa Esophagus Submucosa Trachealis muscle Lumen of trachea (b) Photomicrograph of the tracheal wall (250) Seromucous gland in submucosa Hyaline cartilage Adventitia Anterior (a) Cross section of the trachea and esophagus Copyright © 2011 Pearson Education, Inc. Figure 22.7 Bronchi in the Conducting Zone • Bronchial tree • 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 Superior lobe of right lung Trachea Superior lobe of left lung Left main (primary) bronchus Lobar (secondary) bronchus Segmental (tertiary) bronchus Inferior lobe of left lung Middle lobe Inferior lobe of right lung of right lung (a) The branching of the bronchial tree Copyright © 2011 Pearson Education, Inc. Figure 22.8a Bronchi in the Conducting Zone Mucosa Pseudostratified epithelium Lamina propria Lumen Fibromusculocartilaginous layer Cartilage plate Smooth muscle (b) Photomicrograph of a bronchus (13) Copyright © 2011 Pearson Education, Inc. Figure 22.8b Bronchi in the Conducting Zone • Secondary (lobar) bronchi • 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. Changes in Tissue Composition along Conducting Pathways • Supportive connective tissues change • 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. Structures of the Respiratory Zone • Consists of air-exchanging structures • Respiratory bronchioles—branch from terminal bronchioles • Lead to alveolar ducts • Lead to alveolar sacs Copyright © 2011 Pearson Education, Inc. Structures of the Respiratory Zone Alveoli Alveolar duct Respiratory bronchioles Terminal bronchiole Alveolar duct Alveolar sac (a) Copyright © 2011 Pearson Education, Inc. Figure 22.9a Structures of the Respiratory Zone Respiratory bronchiole Alveolar pores Alveolar duct Alveoli Alveolar sac (b) Copyright © 2011 Pearson Education, Inc. Figure 22.9b Structures of the Respiratory Zone • Alveoli • ~300 million alveoli account for tremendous surface area of the lungs • Surface area of alveoli is ˜140 square meters Copyright © 2011 Pearson Education, Inc. Structures of the Respiratory Zone • Structure of alveoli • Type I cells—single layer of simple squamous epithelial cells • Surrounded by basal lamina • Alveolar and capillary walls plus their basal lamina form • Respiratory membrane Copyright © 2011 Pearson Education, Inc. Structures of the Respiratory Zone • Structures of alveoli (continued) • Type II cells—scattered among type I cells • Are cuboidal epithelial cells • Secrete surfactant • Reduces surface tension within alveoli • Alveolar macrophages Copyright © 2011 Pearson Education, Inc. Anatomy of Alveoli and the Respiratory Membrane Terminal bronchiole Respiratory bronchiole Smooth muscle Elastic fibers Alveolus Capillaries (a) Diagrammatic view of capillary-alveoli relationships Copyright © 2011 Pearson Education, Inc. Figure 22.10a, b Anatomy of Alveoli and the Respiratory Membrane Red blood cell Nucleus of type I (squamous epithelial) cell Alveolar pores Capillary O2 Macrophage Endothelial cell nucleus Alveolus Respiratory membrane Red blood cell Type I cell in capillary of alveolar wall Alveoli (gas-filled Type II (surfactantair spaces) secreting) cell Capillary CO2 Alveolus Alveolar epithelium Fused basement membranes of the alveolar epithelium and the capillary endothelium Capillary endothelium (c) Detailed anatomy of the respiratory membrane Copyright © 2011 Pearson Education, Inc. Figure 22.10c The Respiratory Zone • Features of alveoli • Surrounded by elastic fibers • Interconnect by way of alveolar pores • Internal surfaces • A site for free movement of alveolar macrophages Copyright © 2011 Pearson Education, Inc. Gross Anatomy of the Lungs • Major landmarks of the lungs • 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. Gross Anatomy of the Lungs Anterior View of Thoracic Structures Intercostal muscle Rib Parietal pleura Pleural cavity Visceral pleura Lung Pulmonary artery Trachea Thymus Apex of lung Left superior lobe Oblique fissure Left inferior lobe Right superior lobe Horizontal fissure Right middle lobe Oblique fissure Right inferior lobe Left superior lobe Left main bronchus Oblique fissure Pulmonary vein Impression of heart Oblique fissure Left inferior lobe Hilum 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 Aortic impression Lobules (b) Photograph of medial view of the left lung Figure 22.11a, b Bronchopulmonary Segments Right lung Right superior lobe (3 segments) Left lung Left superior lobe (4 segments) Right middle lobe (2 segments) Right inferior lobe (5 segments) Copyright © 2011 Pearson Education, Inc. Left inferior lobe (5 segments) Figure 22.12 Blood Supply and Innervation of the Lungs • Pulmonary arteries • Deliver oxygen-poor blood to the lungs • Pulmonary veins • Carry oxygenated blood to the heart • Innervation • Sympathetic, parasympathetic, and visceral sensory fibers • Parasympathetic—constrict airways • Sympathetic—dilate airways Copyright © 2011 Pearson Education, Inc. Transverse Cut through the Superior Thorax Vertebra Right lung Parietal pleura Visceral pleura Pleural cavity Posterior Esophagus (in mediastinum) Root of lung at hilum Left main bronchus Left pulmonary artery Left pulmonary vein Left lung Thoracic wall Pulmonary trunk Pericardial membranes Sternum Heart (in mediastinum) Anterior mediastinum 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. The Pleurae • A double-layered sac surrounding each lung • Parietal pleura • Visceral pleura • Pleural cavity • Potential space between the visceral and parietal pleurae • Pleurae help divide the thoracic cavity • Central mediastinum • Two lateral pleural compartments Copyright © 2011 Pearson Education, Inc. Diagram of the Pleurae and Pleural Cavities Intercostal muscle Rib Parietal pleura Pleural cavity Visceral pleura Lung Trachea Thymus 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. Figure 22.11a Location of Lungs in Thoracic Cavity 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 The Mechanisms of Ventilation • Two phases of pulmonary ventilation • Inspiration—inhalation • Expiration—exhalation Copyright © 2011 Pearson Education, Inc. Inspiration • Volume of thoracic cavity increases • Decreases internal gas pressure • Action of the diaphragm • Diaphragm flattens • Action of intercostal muscles • Contraction raises the ribs Copyright © 2011 Pearson Education, Inc. Inspiration • Deep inspiration requires • • • • Scalenes Sternocleidomastoid Pectoralis minor Erector spinae—extends the back Copyright © 2011 Pearson Education, Inc. Expiration • Quiet expiration—chiefly a passive process • Inspiratory muscles relax • Diaphragm moves superiorly • Volume of thoracic cavity decreases • Forced expiration—an active process • Produced by contraction of • Internal and external oblique muscles • Transverse abdominis muscles Copyright © 2011 Pearson Education, Inc. Changes in Thoracic Volume (a) Inspiration Diaphragm and intercostal muscles contract (diaphragm descends and rib cage rises). Thoracic cavity volume increases. Changes in superiorinferior and anteriorposterior dimensions Ribs are elevated and sternum flares as external intercostals contract. Diaphragm moves inferiorly during contraction. Changes in lateral dimensions (superior view) Copyright © 2011 Pearson Education, Inc. External intercostals contract. (b) Expiration Inspiratory muscles relax (diaphragm rises and rib cage descends due to recoil of the costal cartilages). Thoracic cavity volume decreases. Ribs and sternum are depressed as external intercostals relax. Diaphragm moves superiorly as it relaxes. External intercostals relax. Figure 22.14 Changes in Thoracic Volume 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. Trachea Main bronchi Thoracic wall Pleural cavity Lung Lung 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. Pleural Thoracic cavity wall Diaphragm Air 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. Parietal pleura Visceral pleura At rest V P Expanded V P Air flows in Air V P Air flows out V P Figure 22.15 Neural Control of Ventilation • Most important respiratory center • VRG—ventral respiratory group • Located in reticular formation in the medulla oblongata • Neurons generate respiratory rhythm Copyright © 2011 Pearson Education, Inc. Respiratory Centers in the Brain Stem Pons Medulla Ventral respiratory group (VRG) contains rhythm generators whose output drives respiration. Pons Medulla To inspiratory muscles Pontine respiratory centers interact with the medullary respiratory centers to smooth the respiratory pattern. Dorsal respiratory group (DRG) integrates peripheral sensory input and modifies the rhythms generated by the VRG. Diaphragm External intercostal muscles Copyright © 2011 Pearson Education, Inc. Figure 22.16 Neural Control of Ventilation • Respiratory center • 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 Copyright © 2011 Pearson Education, Inc. Location of Peripheral Chemoreceptors Brain 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 Disorders of Lower Respiratory Structures • Bronchial asthma • 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 Copyright © 2011 Pearson Education, Inc. Disorders of Lower Respiratory Structures • Cystic fibrosis (CF)—inherited disease • Exocrine gland function is disrupted • Respiratory system affected by • Oversecretion of viscous mucus Copyright © 2011 Pearson Education, Inc. Disorders of Lower Respiratory Structures • Chronic obstructive pulmonary disease (COPD) • Airflow into and out of the lungs is difficult • Obstructive emphysema • Chronic bronchitis • History of smoking Copyright © 2011 Pearson Education, Inc. Disorders of Lower Respiratory Structures Copyright © 2011 Pearson Education, Inc. Figure 22.18 Alveolar Changes in Emphysema Copyright © 2011 Pearson Education, Inc. Figure 22.19 Disorders of Upper Respiratory Structures • Epistaxis—nosebleed Copyright © 2011 Pearson Education, Inc. The Respiratory System Throughout Life • By week 4 of development • 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. The Respiratory System Throughout Life 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 Aging of the Respiratory System • 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.