CHAPTER 23LECTURE OUTLINEI. INTRODUCTIONA. The two systems that cooperate to supply O2 and eliminate CO2 are the cardiovascular and the respiratory system.1. The respiratory system provides for gas exchange.2. The cardiovascular system transports the respiratory gases.3. Failure of either system has the same effect on the body: disruption of homeostasis and rapid death of cells from oxygen starvation and buildup of waste products.B. Respiration is the exchange of gases between the atmosphere, blood, and cells. It takes place in three basic processes: ventilation (breathing), external (pulmonary) respiration, and internal (tissue) respiration.II. RESPIRATORY SYSTEM ANATOMYA. The respiratory system consists of the nose, pharynx, larynx, trachea, bronchi, and lungs (Figure 23.1).1. The upper respiratory system refers to the nose, pharynx, and associated structures. The lower respiratory system refers to the larynx, trachea, bronchi, and lungs.2. The conducting system consists of a series of cavities and tubes - nose, pharynx, larynx, trachea, bronchi, bronchiole, and terminal bronchioles - that conduct air into the lungs. The respiratory portion consists of the area where gas exchange occurs - respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.3. The branch of medicine that deals with the diagnosis and treatment of diseases of the ear, nose, and throat is called otorhinolaryngology.B. Nose1. The external portion of the nose is made of cartilage and skin and is lined with mucous membrane. Openings to the exterior are the external nares.2. The external portion of the nose is made of cartilage and skin and is lined with mucous membrane (Figure 23.2a).3. The bony framework of the nose is formed by the frontal bone, nasal bones, and maxillae (Figure 23.2).4. The interior structures of the nose are specialized for warming, moistening, and filtering incoming air; receiving olfactory stimuli; and serving as large, hollow resonating chambers to modify speech sounds.5. The internal portion communicates with the paranasal sinuses and nasopharynx through the internal nares.6. The inside of both the external and internal nose is called the nasal cavity. It is divided into right and left sides by the nasal septum. The anterior portion of the cavity is called the vestibule.7. The surface anatomy of the nose is shown in Figure 23.3.8. Rhinoplasty (“nose job”) is a surgical procedure in which the structure of the externalnose is altered for cosmetic or functional reasons. (Clinical Connection)C. Pharynx1. The pharynx (throat) is a muscular tube lined by a mucous membrane (Figure 23.2).2. The anatomic regions are the nasopharynx, oropharynx, and laryngopharynx.3. The nasopharynx functions in respiration. Both the oropharynx and laryngopharynx function in digestion and in respiration (serving as a passageway for both air and food).4. A Tonsillectomy is the surgical removal of the tonsils (Clinical Connection)D. Larynx1. The larynx (voice box) is a passageway that connects the pharynx with the trachea.2. It contains the thyroid cartilage (Adam’s apple); the epiglottis, which prevents food from entering the larynx; the cricoid cartilage, which connects the larynx and trachea;and the paired arytenoid, corniculate, and cuneiform cartilages (Figure 23.4).E. The Structures of Voice Production1. The larynx contains vocal folds (true vocal cords), which produce sound. Taunt vocalfolds produce high pitches, and relaxed vocal folds produce low pitches (Figure 23.5).2. Sound originates from the vibration of the vocal folds, but other structures are necessary for converting the sound into recognizable speech.3. Laryngitis is an inflammation of the larynx that is usually caused by respiratory infection or irritants. Cancer of the larynx is almost exclusively found in smokers (Clinical Connection).F. Trachea1. The trachea (windpipe) is anterior to the esophagus (Figure 23.6)2. It extends from the larynx to the primary bronchi (Figure 23.7).3. It is composed of smooth muscle and C-shaped rings of cartilage and is lined with pseudostratified ciliated columnar epithelium.a. The cartilage rings keep the airway open.b. The cilia of the epithelium sweep debris away from the lungs and back to the throat to be swallowed.4. Two methods of bypassing obstructions from the respiratory passageways are tracheostomy and intubation. (Clinical Connection)G. Bronchi1. The trachea divides into the right and left pulmonary bronchi (Figure 23.7).2. The bronchial tree consists of the trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, and terminal bronchioles.3. Changes in histology reflect changes in function is the structures of the bronchial tree.a. The mucus membrane changes from ciliated pseudostratified epithelium withmany goblet cells (in the largest bronchi) to non-ciliated cuboidal epithelium in the smallest bronchioles.b. The c-rings of the trachea are replaced by plates of cartilage (in the bronchi) and eventually cartilage disappears completely in the bronchioles. c. As the amount of cartilage decreases the amount of smooth muscle increases.H. Lungs1. Lungs are paired organs in the thoracic cavity; they are enclosed and protected by thepleural membrane (Figure 23.8).a. The parietal pleura is the outer layer which is attached to the wall of the thoracic cavity.b. The visceral pleura is the inner layer, covering the lungs themselves.c. Between the pleurae is a small potential space, the pleural cavity, which contains a serous lubricating fluid secreted by the membranes.d. The lungs extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly.e. Injuries to the chest wall that allow air to enter the intrapleural space either from the outside or from the alveoli cause pneumothorax, filling the pleural cavity with air. (Clinical Connection).2. The right lung has three lobes separated by two fissures; the left lung has two lobes separated by one fissure and a depression, the cardiac notch (Figure 23.9).a. The secondary bronchi give rise to branches called tertiary (segmental) bronchi, which supply segments of lung tissue called bronchopulmonary segments.b. Each bronchopulmonary segment consists of many small compartments called lobules, which contain lymphatics, arterioles, venules, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli(Figure 23.10).3. Alveolia. Alveolar walls consist