Thibodeau: Anatomy and Physiology, 5/e. Chapter 23: Anatomy of the Respiratory System

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1 Thibodeau: Anatomy and Physiology, 5/e Chapter 23: Anatomy of the Respiratory System Naturally, the structure, location, and function of the organs of the respiratory system are the focus of this entire chapter. It is important to take the time to allow students to master the contents of the chapter because of the prominent role the respiratory system plays in homeostasis. This system functions as an air distributor and a gas exchanger so that oxygen may be supplied to, and carbon dioxide removed from, the body's cells. Since most of our trillions of cells lie too far from air to exchange gases directly with it, air must first exchange gases with blood. Then blood must circulate, and finally, blood and cells must exchange gases. This process demonstrates the interaction necessary between this system and the circulatory system. All parts of the respiratory system except the alveoli function as air distributors. Only the alveoli and the tiny passageways that open into them serve as gas exchangers. Objectives After students have completed this chapter, they should be able to: 1. List and locate the organs of the respiratory system. 2. List the generalized functions of the respiratory system. 3. Describe and correlate the anatomy of the nose with its specialized functions. 4. Locate the paranasal sinuses in the skull and describe how they drain into the nose. 5. List the anatomical divisions of the pharynx and name the openings into and between its divisions. 6. Identify and locate the tonsils. 7. Discuss the location, structure, and specialized functions of the thorax. 8. Describe the structure and function of the trachea, bronchi, bronchioles, and alveoli. 9. Identify the lobes of the lungs and the bronchopulmonary segments. 10. Discuss the gross surface anatomy and generalized functions of the lungs. 11. Discuss the structure and function of the thorax and mediastinum in respiration. Lecture Outline I. Overview of the Respiratory System (p. 686) A. Functions of the respiratory system 1. Air distribution 2. Gas exchange 3. Filters, warms, and humidifies air 4. Regulates ph B. Structural plan of the respiratory system (Fig. 23-1) 1. Upper respiratory tract 2. Lower respiratory tract 3. Accessory structures II. Upper Respiratory Tract (p. 681) A. Nose

2 Chapter 23: Anatomy of the Respiratory System 2 1. Structure of the nose a. External nose 1) Two nasal bones and cartilage b. Internal nose (nasal cavity) (Fig. 23-2) 1) Palate (palatine bones and palatine process of maxilla = hard palate; soft palate just posterior) 2) Cribriform plate of the ethmoid bone 3) Septum (perpendicular plate of the ethmoid bone, the vomer, and cartilage (Fig. 23-2) 4) Nasal cavity (Figs. 23-3, 23-5) a) Anterior nares (external opening) b) Vestibule (cavity just inside anterior nares) c) Meati (below each turbinate bone superior, middle, and inferior) d) Turbinates or conchae (superior, middle and inferior) e) Vibrissae (hairs in vestibule) f) Posterior nares (open into the nasopharynx) c. Nasal mucosa (starts just posterior to vestibule) 1) Respiratory mucosa a) Below superior conchae b) Many goblet cells and ciliated 2) Olfactory epithelium a) Superior conchae and up b) Many olfactory nerve cells d. Paranasal sinuses (Fig. 23-5) 1) Lined with respiratory mucosa 2) Four groups of sinuses a) Frontal b) Maxillary c) Sphenoid d) Ethmoid 2. Functions of the nose (p. 688) a. Passageway for air b. Filtering of air c. Warming of air d. Moistening of air 1) Lacrimal ducts drain into the inferior nasal meatus

3 Chapter 23: Anatomy of the Respiratory System 3 B. Pharynx (Fig. 23-6) e. Chemical examination of air 1. Structure of the pharynx a. Nasopharynx (above soft palate) 1) Auditory (eustachian) tubes opening into it 2) Pharyngeal tonsils (adenoids) on posterior wall 3) Posterior nares b. Oropharynx (posterior to fauces) 1) Fauces (opening into mouth) 2) Palatine tonsils 3) Lingual tonsils c. Laryngopharynx (hyoid bone to esophagus) 1) Opening into larynx 2. Functions of the pharynx C. Larynx (Figs. 23-7, 23-8, 23-9) 2) Opening into esophagus a. Common pathway for respiratory and digestive tracts b. Phonation (speech production) 1. Location of the larynx (p. 690) a. Below tongue to trachea 2. Structure of the larynx a. Cartilage structure b. Ciliated mucous membrane lining c. Epiglottis (a flap that can close over the glottis) d. Vestibular folds (false vocal cords) e. True vocal folds f. Glottis (the true vocal folds and the opening into the larynx) g. Vestibule (area above vestibular folds) h. Ventricle (area between the vestibular folds and true vocal folds) 3. Cartilages of the larynx (Figs. 23-7, 23-8) a. Thyroid cartilage (largest; gives shape) b. Epiglottis (flap that can cover glottis) c. Arytenoid cartilages (move vocal folds) 4. Muscles of the larynx a. Intrinsic

4 Chapter 23: Anatomy of the Respiratory System 4 1) Control vocal fold length b. Extrinsic 1) Move larynx as a whole 5. Functions of the larynx a. Air passageway b. Filtration, warming, and humidification of air c. Voice production III. Lower Respiratory Tract (Fig ) A. Trachea 1. Structure of the trachea (Figs , 23-12) a. C-shaped cartilage rings b. Smooth muscle c. Pseudostratified ciliated columnar epithelium lining 2. Function of the trachea a. Open passageway for air B. Bronchi and alveoli (Fig ) 1. Structure of the bronchi (Fig ) a. Primary bronchi b. Secondary bronchi c. Tertiary bronchi d. Bronchioles (Fig ) e. Alveolar ducts (Fig ) f. Alveoli (Fig ) 2. Structure of the alveoli (Figs , 23-15, 23-16) a. Respiratory membrane 1) Surfactant 2) Alveolar epithelium 3) Basement membranes 4) Capillary endothelium 3. Functions of the bronchi and alveoli a. Distribution of air b. Cleansing, warming, and humidifying air c. Gas exchange C. Lungs (p. 698) 1. Structure of the lungs (Figs , 23-18) a. Hilum (where blood vessels and bronchi enter each lung) b. Base (surface against diaphragm)

5 Chapter 23: Anatomy of the Respiratory System 5 D. Thorax (Fig ) c. Apex (upper end just above clavicles) d. Costal surface (against the ribs) e. Fissures (divide the lung into lobes) 1) Oblique fissure (one in each lung) 2) Horizontal fissure (right lung only) f. Lobes (a secondary bronchus to each lobe) 1) Superior 2) Middle (right lung only) 3) Inferior g. Bronchopulmonary segments (a tertiary bronchus to each segment) (Figs , 23-18) 2. Functions of the lungs 1) 10 segments in right lung 2) 8 segments in left lung a. Air distribution (bronchi and bronchioles) b. Gas exchange (in the alveoli) c. Provide air-tight bag for thorax to pull and push on 1) Movement of air in and out of lungs 1. Structure of the thoracic cavity (p. 700) a. Parietal serous pleura b. Visceral serous pleura c. Pleural space (pleural cavity) 1) Contains pleural fluid for lubricant d. In pleuritis (inflammation of the pleura) the membranes do not slide nicely over one another, and painful breathing results. 2. Functions of the thoracic cavity IV. Cycle of Life: Respiratory System (p. 700) A. Premature birth B. Respiratory disease a. Change in size for respiration 1) Inspiration a) Lifting up chest and flattening diaphragm 2) Expiration C. Reduction in respiratory efficiency in older adulthood V. The Big Picture: Anatomy of the Respiratory System (p. 701) a) Lowering chest and relaxing diaphragm

6 Chapter 23: Anatomy of the Respiratory System 6 A. Distribution of air and exchange of gases B. Interdependent on nervous, circulatory, muscular, and immune systems VI. Mechanisms of Disease: Disorders Associated with Respiratory Anatomy (p. 701) A. Disorders of the upper respiratory tract 1. Inflammation and infection (upper respiratory infection) a. Rhinitis b. Pharyngitis c. Laryngitis 2. Anatomical disorders a. Deviated septum b. Sleep apnea c. Epistaxis (nosebleed) B. Disorders of the lower respiratory tract 1. Lower respiratory infection a. Acute bronchitis b. Pneumonia c. Tuberculosis (TB) 2. Lung cancer (Box 23-7) 3. Pulmonary radiology (Fig ) 4. Terminology 5. Specialized radiographs (Fig )