Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture Slides prepared by Vince Austin, University of Kentucky 13 The Respiratory System

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory System – know this Consists of the respiratory and conducting zones Respiratory zone  Site of gas exchange  Consists of bronchioles, alveolar ducts, and alveoli Conducting zone  Provides rigid conduits for air to reach the sites of gas exchange  Includes all other respiratory structures (e.g., nose, nasal cavity, pharynx, trachea)  Respiratory muscles – diaphragm and other muscles that promote ventilation

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Major Functions of the Respiratory System – know this To supply the body with oxygen and dispose of carbon dioxide Respiration – four distinct processes must happen  Pulmonary ventilation – moving air into and out of the lungs  External respiration – gas exchange between the lungs and the blood  Transport – transport of oxygen and carbon dioxide between the lungs and tissues  Internal respiration – gas exchange between systemic blood vessels and tissues

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Function of the Nose and Sinuses - understand The only externally visible part of the respiratory system that functions by:  Providing an airway for respiration  Moistening and warming the entering air  Filtering inspired air and cleaning it of foreign matter  Serving as a resonating chamber for speech  Housing the olfactory receptors

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  The nose is divided into two regions  The external nose, including the root, bridge, dorsum nasi, and apex  The internal nasal cavity  Philtrum – a shallow vertical groove inferior to the apex  The external nares (nostrils) are bounded laterally by the alae Structure of the Nose - understand

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Structure of the Nose – know this

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nasal Cavity – know this Vestibule – nasal cavity superior to the nares  Vibrissae – hairs that filter coarse particles from inspired air Olfactory mucosa  Lines the superior nasal cavity  Contains smell receptors Respiratory mucosa  Lines the balance of the nasal cavity  Glands secrete mucus containing lysozyme and defensins to help destroy bacteria

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Inspired air is:  Humidified by the high water content in the nasal cavity  Warmed by rich capillaries  Ciliated mucosal cells remove contaminated mucus (upward and into digestive tract at pharynx) Nasal Cavity

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  During inhalation the conchae and nasal mucosa:  Filter, heat, and moisten air  During exhalation these structures:  Reclaim heat and moisture  Minimize heat and moisture loss Functions of the Nasal Mucosa and Conchae - understand

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pharynx - understand Funnel-shaped tube of skeletal muscle that connects to the:  Nasal cavity and mouth superiorly  Larynx and esophagus inferiorly Extends from the base of the skull to the level of the sixth cervical vertebra

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Larynx (Voice Box) – know this Attaches to the hyoid bone and opens into the laryngopharynx superiorly Continuous with the trachea posteriorly The three functions of the larynx are:  To provide a patent (“always open”) airway  To act as a switching mechanism to route air and food into the proper channels  To function in voice production

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Attach the arytenoid cartilages to the thyroid cartilage Composed of elastic fibers that form mucosal folds called true vocal cords  The medial opening between them is the glottis  They vibrate to produce sound as air rushes up from the lungs Vocal Ligaments - understand

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Vocal Production – know this Speech – intermittent release of expired air while opening and closing the glottis Pitch – determined by the length and tension of the vocal cords Loudness – depends upon the force at which the air rushes across the vocal cords The pharynx resonates, amplifies, and enhances sound quality Sound is “shaped” into language by action of the pharynx, tongue, soft palate, and lips

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings  Air reaching the bronchus is:  Warm and cleansed of impurities  Saturated with water vapor  Bronchi subdivide into secondary bronchioles, each supplying a lobe of the lungs  Air passages undergo 23 orders of branching in the lungs Conducting Zone: Bronchi - understand

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Conducting Zone: Bronchial Tree – know this  Tissue walls of bronchi mimic that of the trachea  As conducting tubes become smaller, structural changes occur  Cartilage support structures change  Epithelium types change  Trachea and bronchi = ciliated columnar epithelium  Bronchioles = simple cuboidal  Amount of smooth muscle increases

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Conducting Zone: Bronchial Tree – know this  Bronchioles  Consist of cuboidal epithelium  Have a complete layer of circular smooth muscle  Lack cartilage support and mucus- producing cells

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory Zone - understand  Defined by the presence of alveoli; begins as terminal bronchioles feed into respiratory bronchioles  Respiratory bronchioles lead to alveolar ducts, then to terminal clusters of alveolar sacs composed of alveoli  Approximately 300 million alveoli:  Account for most of the lungs’ volume  Provide tremendous surface area for gas exchange

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Respiratory Zone – understand Simple squamous epithelium

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of the Lungs - understand  Lungs occupy all of the thoracic cavity except the mediastinum  Root – site of vascular and bronchial attachments  Costal surface – anterior, lateral, and posterior surfaces in contact with the ribs  Apex – narrow superior tip  Base – inferior surface that rests on the diaphragm  Hilus – indentation that contains pulmonary and systemic blood vessels

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lungs – know this  Cardiac notch (impression) – cavity that accommodates the heart  Left lung – separated into upper and lower lobes by the oblique fissure  Right lung – separated into three lobes by the oblique and horizontal fissures  There are 10 bronchopulmonary segments in each lung

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood Supply to Lungs - understand Lungs are perfused by two circulations: pulmonary and bronchial Pulmonary arteries – supply systemic venous blood to be oxygenated  Branch profusely, along with bronchi  Ultimately feed into the pulmonary capillary network surrounding the alveoli Pulmonary veins – carry oxygenated blood from respiratory zones to the heart

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Breathing – know this  Breathing, or pulmonary ventilation, consists of two phases  Inspiration – air flows into the lungs  Expiration – gases exit the lungs

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pressure Relationships in the Thoracic Cavity - understand  Respiratory pressure is always described relative to atmospheric pressure  Atmospheric pressure (P atm )  Pressure exerted by the air surrounding the body  Negative respiratory pressure is less than P atm  Positive respiratory pressure is greater than P atm

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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Surface tension – the attraction of liquid molecules to one another at a liquid- gas interface The liquid coating the alveolar surface is always acting to reduce the alveoli to the smallest possible size Surfactant, a detergent-like complex, reduces surface tension and helps keep the alveoli from collapsing Alveolar Surface Tension - understand

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lung Compliance - understand The ease with which lungs can be expanded Specifically, the measure of the change in lung volume that occurs with a given change in transpulmonary pressure Determined by two main factors Distensibility of the lung tissue and surrounding thoracic cage Surface tension of the alveoli

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Factors That Diminish Lung Compliance - know Scar tissue or fibrosis that reduces the natural resilience of the lungs Blockage of the smaller respiratory passages with mucus or fluid Reduced production of surfactant Decreased flexibility of the thoracic cage or its decreased ability to expand Examples include:  Deformities of thorax  Ossification of the costal cartilage  Paralysis of intercostal muscles

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Emphysema - know   Emphysema is a type of chronic obstructive pulmonary disease (COPD) involving damage to the air sacs (alveoli) in the lungs. As a result, your body does not get the oxygen it needs. Emphysema makes it hard to catch your breath. You may also have a chronic cough and have trouble breathing during exercise.chronic obstructive pulmonary disease The most common cause is cigarette smoking. If you smoke, quitting can help prevent you from getting the disease. If you already have emphysema, not smoking might keep it from getting worse. Treatment is based on whether your symptoms are mild, moderate or severe. Treatments include inhalers, oxygen, medications and sometimes surgery to relieve symptoms and prevent complications.

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Lung Cancer - understand  A&feature=related A&feature=related  &NR=1&feature=fvwp &NR=1&feature=fvwp