Chapter 21 (Respiratory System) PDF

CHAPTER 22 The Respiratory System Human Anatomy Copyright Copyright©©2011 2011Pearson PearsonEducation, Educatio, Inc. Inc. The Respiratory System Supplies body with oxygen Disposes of carbon dioxide Four processes in respiration Pulmonary ventilation External respiration Transport of respiratory ga...

CHAPTER 22 The Respiratory System Human Anatomy Copyright Copyright©©2011 2011Pearson PearsonEducation, Educatio, Inc. Inc. The Respiratory System Supplies body with oxygen Disposes of carbon dioxide Four processes in respiration Pulmonary ventilation External respiration Transport of respiratory gases Internal respiration Functional Anatomy of the Respiratory System Respiratory organs PLAY Nose, nasal cavity, and paranasal sinuses Pharynx, larynx, and trachea Bronchi and smaller branches Lungs and alveoli Respiratory Tracts Organs of the Respiratory System Nasal cavity Nostril Larynx Trachea Carina of trachea Right main (primary) bronchus Right lung Parietal pleura Oral cavity Pharynx Left main (primary) bronchus Bronchi Alveoli Left lung Diaphragm Organs of the Respiratory System Divided into: Conducting zone Respiratory zone The Nose Provides an airway for respiration Moistens and warms air Filters inhaled air Resonating chamber for speech Houses olfactory receptors The Nasal Cavity External nares – nostrils Divided by – nasal septum Continuous with nasopharynx Basic Anatomy of the Upper Respiratory Tract Two types of mucosa Olfactory mucosa – houses olfactory receptors Respiratory mucosa – lines nasal cavity Basic Anatomy of 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 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 Epiglottis Vestibular fold Thyroid cartilage Vocal fold Cricoid cartilage Thyroid gland Lingual tonsil Hyoid bone Respiratory Mucosa Consists of: Pseudostratified ciliated columnar epithelium Goblet cells within epithelium lysozyme Underlying layer of lamina propria Mucous cells Secrete mucus Cilia move contaminated mucus posteriorly Nasal Conchae Superior and middle – part of the ethmoid bone Inferior – a separate bone Project medially from the lateral wall of the nasal cavity Particulate matter – deflected to mucus-coated surfaces The Paranasal Sinuses Same air-processing functions as nasal cavity lined by same mucosa The Pharynx Funnel-shaped passageway Connects nasal cavity and mouth Divided into three locations Nasopharynx, oropharynx, and laryngopharynx Type of mucosal lining varies 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 (auditory) tube Ciliated pseudostratified epithelium The Oropharynx Arch-like entranceway – fauces Extends from soft palate to the epiglottis Epithelium is stratified squamous epithelium protective Two types of tonsils in the oropharynx Palatine tonsils – in the lateral walls of the fauces Lingual tonsil – covers the posterior surface of the tongue The Laryngopharynx Passageway for both food and air Lined with stratified squamous epithelium Continuous with the esophagus and larynx The Larynx Three functions Voice production Provides an open airway Routes air and food into the proper channels 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 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 (b) Vocal folds in open position; open glottis The Larynx Voice production Length of the vocal folds changes with pitch Loudness depends on the force of air across the vocal folds Innervation of the larynx – recurrent laryngeal nerves The Trachea Descends into the mediastinum Divides into two main bronchi C-shaped cartilage rings keep airway open 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 Seromucous gland in submucosa Hyaline cartilage Adventitia Anterior (a) Cross section of the trachea and esophagus (b) Photomicrograph of the tracheal wall (250×) Bronchi in the Conducting Zone Bronchial tree – extensively branching respiratory passageways Primary bronchi (main bronchi) – largest bronchi Right main bronchi – wider, shorter and steeper than the left 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 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 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 thinner; no cilia/mucus Smooth muscle becomes important The Respiratory Zone Consists of air-exchanging structures Respiratory bronchioles – branch from terminal bronchioles Lead to alveolar ducts Lead to alveolar sacs Alveoli Alveolar duct Respiratory bronchioles Terminal bronchiole Alveolar duct Alveolar sac The Respiratory Zone Alveoli wall consists of type I cells and basal laminae Very thin Scattered among type I cells Cuboidal epithelial cells – type II cells Secrete surfactant Terminal bronchiole Respiratory bronchiole Smooth muscle Elastic fibers Alveolus Capillaries (a) Diagrammatic view of capillary-alveoli relationships 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 (c) Detailed anatomy of the respiratory membrane Capillary CO2 Alveolus Alveolar epithelium Fused basement membranes of the alveolar epithelium and the capillary endothelium Capillary endothelium 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 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 Diagram of the Pleurae and Pleural Cavities Gross Anatomy of the Lungs Anterior View of Thoracic Structures Bronchopulmonary Segments Bronchopulmonary Segments 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) 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 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. The Mechanisms of Ventilation Two phases of pulmonary ventilation Inspiration – inhalation Expiration – exhalation Inspiration Volume of thoracic cavity increases Decreases internal gas pressure Action of the diaphragm – diaphragm flattens Action of intercostal muscles – contraction raises the ribs Deep inspiration requires Scalenes, sternocleidomastoid, and pectoralis minor Erector spinae – extends the back 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: The oblique and transversus abdominis muscles Respiratory Volumes Changes in Thoracic Volume PLAY (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) 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. Neural Control of Ventilation Respiratory center – generates baseline respiration rate In the reticular formation of the medulla oblongata Chemoreceptors – (detecting oxygen, carbon dioxide and acid) Central chemoreceptors – located in medulla Peripheral chemoreceptors Aortic bodies Carotid bodies 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 Disorders of Lower Respiratory Structures Bronchial asthma – a type of allergic inflammation A hypersensitivity to irritants in the air or to stress Asthma attacks characterized by: Contraction of bronchiole smooth muscle Secretion of mucus in airways 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 Disorders of Lower Respiratory Structures 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