Respiratory Outline

Respiratory Outline - Chapter 23: The Respiratory System I....

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Chapter 23: The Respiratory System I. The Respiratory System: An Introduction, p. 814 Organization of the Respiratory System, p. 814 The respiratory system is divided into the upper respiratory system , above the larynx, and the lower respiratory system , from the larynx down. The respiratory tract consists of a conducting portion (from the nasal cavity to the terminal bronchioles ) and a respiratory portion (the respiratory bronchioles and alveoli ). Alveoli are the air-filled pockets within the lungs where all gas exchange takes place. The Respiratory Epithelium For gases to exchange efficiently, the walls of the alveoli must be very thin, and the surface area must be very great. The distance from the inside of an alveolus to and alveolar capillary is less than 1 micrometer. The surface area within the lungs is about 35 times the surface area of the body. The respiratory mucosa , consisting of an epithelial layer and an areolar layer, lines the conducting portion of the respiratory system. In the upper respiratory system, trachea and bronchi: The lamina propria , underlying the areolar tissue, contains mucous glands that secrete onto the epithelial surface. In the conducting portion of the lower respiratory system: The lamina propria contains smooth muscle cells that encircle the lumen of the bronchioles. The structure of the respiratory epithelium changes along the respiratory tract. The exchange surfaces of the alveoli are lined with alveolar epithelium : a very delicate, simple squamous epithelium containing scattered, specialized cells. The respiratory defense system consists of a series of filtration mechanisms that remove particles and pathogens: - Goblet cells and mucous glands produce mucus that bathes exposed surfaces. - Cilia sweep debris trapped in mucus toward the pharynx (mucus escalator ). - Filtration in the nasal cavity removes large particles. - Small particles that reach the lungs can be engulfed by alveolar macrophages. II. The Upper Respiratory System, p. 817 The Nose and Nasal Cavity, p. 817 Air enters the respiratory system through the nostrils or external nares into the nasal vestibule , which contains the first particle filtration system: nasal hairs. The nasal septum divides the nasal cavity into left and right. Mucous secretions from the paranasal sinus and tears keep the nasal cavity moist and clean. The superior portion of the nasal cavity is the olfactory region which provides the sense of smell. Air flows from the vestibule to the internal nares through the superior , middle and inferior meatuses . The meatuses are constricted passageways that produce air turbulence, giving incoming air time to warm and humidify, and particles to be trapped. The hard palate
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This note was uploaded on 12/29/2011 for the course BIOLOGY 24011 taught by Professor Pan during the Fall '11 term at HCCS.

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Respiratory Outline - Chapter 23: The Respiratory System I....

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