Chapter 9 Respiratory System PDF

1 ANATOMY PHYSIOLOGY Respiratory System BHS407 Dec-24  LEARNING OUTCOMES At the end of the lessons, student will be able to: Understand the anatomy of the respiratory system Understand the function of the respiratory...

1 ANATOMY PHYSIOLOGY Respiratory System BHS407 Dec-24  LEARNING OUTCOMES At the end of the lessons, student will be able to: Understand the anatomy of the respiratory system Understand the function of the respiratory system Understand the process of gas exchange and gas transport Understand the regulation of respiration Dec-24 BHS407 2  The structures of the respiratory system can be divided into the upper respiratory tract and the lower respiratory tract. The upper respiratory tract refers to the nose, pharynx, nasal cavity and paranasal sinuses. The lower respiratory tract includes the larynx, trachea, bronchi, bronchioles and alveoli. Dec-24 BHS407 3  The respiratory system can also be separated into a conducting zone and a respiratory zone. The conducting zone refers to structures that transport air but play no role in gas exchange. It includes: nasal cavity, nasopharynx, oropharynx, laryngopharynx, larynx, trachea, bronchi, and all bronchioles except for respiratory bronchioles. These structures are involved in transporting, filtering, humidifying, and warming air. Dec-24 BHS407 4  The respiratory zone refers to structures where exchange of O2 and CO2 occurs. Sites of gas exchange are known as alveoli (single alveolus). All respiratory zone structures contain alveoli and include: respiratory bronchioles, alveolar ducts, and alveolar sacs. Dec-24 BHS407 5 BHS407 6 Dec-24  The Respiratory System: An Introduction Functions of the respiratory system Gas exchange between air and circulating blood Moving air from the exchange surface of the lungs Protection of respiratory surfaces Production of sound Provision for olfactory sensations Dec-24 BHS407 7  Respiratory Mucosa Respiratory epithelium (Columnar and pseudostratified) and underlying connective tissue Respiratory membrane, supported by lamina propria, changes along tract Lines conducting portion of respiratory tract Protected from contamination by respiratory defense system Dec-24 BHS407 8  Nasal Cavity Nasal septum = divider between nasal cavity Hard palate = floor for nasal cavity ; separate between nasal cavity and mouth cavity Bony ridges called conchae = increase surface area of nasal cavity and cause air to churn Dec-24 BHS407 9  Paranasal sinus open into nasal cavity and line with mucous membrane Nasolacrimal ducts = eyes to nasal cavity Olfactory receptor at superior part of nasal cavity Cavity is lining with stratified squamous epithelium tissue with coarse hair = trap dust or large particles in the air Near to pharynx, cavity lining by pseudostratified columnar associated with goblet cells Sneeze reflex Dec-24 BHS407 10 11 BHS407 Dec-24  The pharynx Shared by the digestive and respiratory systems Divided into three sections: – Nasopharynx (pseudostratified columnar) – superior portion ; enclose by uvulva during swallowing – Oropharynx (Stratified squamous) – continuous with the oral cavity – Laryngopharynx – from tip of epiglottis until esophagus Dec-24 BHS407 12  Dec-24 BHS407 13  The Larynx Air passes through the glottis on the way to the lungs (C4 – C6) Larynx protects the glottis 9 Cartilages of the larynx Three large cartilages – Thyroid, cricoid, and epiglottis Paired cartilages – Cuneiform, Corniculate and Arytenoids – Arytenoids : change the position and tension of vocal cords Dec-24 BHS407 14 BHS407 15 Dec-24  Vocal cord Primary source of voice production Two pairs of ligament at thyroid cartilage extended posteriorly to arytenoid cartilage Superior ligament – vestibular fold (false vocal cord) Inferior ligament – true vocal cord Control by posterior and lateral cricoarytenoid muscle Dec-24 BHS407 16  Moving air pass through vocal cord cause them to vibrate and produce sound Male has thick and long vocal fold (influence by testosterone) – Vibrate more slowly and produce low pitch voice The articulators (tongue, palate, cheek and lips) – Control laryngeal airflow to strengthen it or weaken it as a sound source. – https://www.youtube.com/watch?v=JF8rlKu SoFM Dec-24 BHS407 17  Dec-24 BHS407 18  The laryngeal musculature Muscles of the neck and pharynx position and stabilize the larynx When swallowing, these muscles elevate the larynx Bend the epiglottis over the glottis Intrinsic muscles control tension on the vocal folds and open the glottis Dec-24 BHS407 19 20 BHS407 Dec-24  Trachea Inferior to cricoid cartilage Extends from the larynx to the mediastinum Divide into left and right primary bronchi at 5th Thoracic vertebra Lined by pseudostratified epithelium associated with goblet cells - mucus secretion – due to its abundant seromucous glands. Dec-24 BHS407 21  16 – 20 C shape of hyaline cartilage Prevents air passage from collapsed Strengthen by ligament Posterior wall of trachea has no cartilage - connective tissue and smooth muscle Contract during cough Provides the esophagus with room to expand when a large bolus of food is swallowed Dec-24 BHS407 22 BHS407 23 Dec-24  Anterior to esophagus The last tracheal cartilage is expanded and contains a sensitive posterior projection known as the carina. – The mucous membrane in the carina is the most sensitive than the larynx and trachea – Trigger cough reflex The right primary bronchus is more vertical, shorter and broader than the left Dec-24 BHS407 24  Dec-24 25 BHS407  Bronchi The trachea divides into 2 main bronchi. The right main bronchus is wider, shorter, and more vertical than the left. – More likely to be obstructed by a foreign object. Air reaching the bronchi has been significantly filtered, warmed, and humidified. – Line by pseudostratified columnar epithelium and supported by C shape cartilage Dec-24 BHS407 26  The bronchial tree Each main bronchus divides into lobar bronchi (secondary bronchi). There are 3 lobar bronchi on the right (one for each of the 3 lobes of the right lung) and 2 lobar bronchi on the left (one for each of the 2 lobes of the left lung). Dec-24 BHS407 27  Lobar bronchi divide to yield segmental bronchi (tertiary bronchi) that divide to yield smaller and smaller bronchi until about 23 branchings have occurred. Tertiary bronchi supply air to a single bronchopulmonary segment Once the passageways have a diameter