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CHAPTER 24 The Respiratory System © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-2 Learning Outcomes 24.1 Explain the functions of the respiratory system. 24.2 Explain the difference between internal respiration and external respiration. 24.3 Describe how the larynx produces voice sounds. 24.4 List the structures contained within the lungs. 24.5 Describe the coverings of the lungs and chest cavity. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-3 Learning Outcomes (cont.) 24.6 Describe the events that lead to the inspiration and expiration of air. 24.7 Explain how the brain controls breathing and how normal breathing patterns can be disrupted. 24.8 Describe how oxygen is transported from the lungs to body cells. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-4 Learning Outcomes (cont.) 24.9 Describe how carbon dioxide is transported from body cells to the lungs. 24.10List and explain various respiratory volumes and tell how they are used to diagnose respiratory problems. 24.11Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the respiratory system. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-5 Introduction • Function – Move air in and out of lungs (ventilation) – Delivers oxygen (O2) – Removes carbon dioxide (CO2) CO2 • External respiration – Occurs in the lungs • Internal respiration – Occurs in the hemoglobin O2 O2 Lungs CO2 CO2 O2 © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-6 Organs of the Respiratory System Nose Pharynx Larynx Trachea Bronchial tree Lungs © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-7 Nasal Cavity • Nasal septum divides the cavity into right and left portions – Nares – openings of the nose • Nasal conchae extend from walls of nasal cavity • Mucous membrane warms and moistens the air • Cilia help eliminate particles © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-8 Paranasal Sinuses • Air-filled spaces within the skull bones – Open into the nasal cavity • Reduce the weight of the skull • Equalize pressure • Give the voice its certain tone • Skull bones with sinuses include: – – – – Frontal Sphenoid Ethmoid Maxillae bones © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-9 Pharynx and Larynx • Pharynx – Serves both the respiratory and digestive systems • Larynx – Also called the “voice box” – Moves air in and out of the trachea and produces voice – Composed of three cartilages: • Thyroid cartilage • Epiglottic cartilage • Cricoid cartilage © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-10 Vocal Cords • Stretched between the thyroid cartilage and Posterior the cricoid cartilage Portion • Upper – false cords of Tongue • Lower – true vocal cords • Glottis – the opening between the vocal cords Glottis False Vocal Cords True Vocal Cords • Stretch = pitch of voice © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-11 Trachea • Referred to as the windpipe • Tubular organ made of rings of cartilage and smooth muscle • Extends from the larynx to the bronchi • Lined with cells possessing cilia (microscopic hair-like projections) Trachea Cilia move mucus up to the throat, where it is swallowed. Smoking destroys cilia. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-12 Bronchial Tree • Bronchi Bronchi – Primary: First branches off trachea – Secondary – Tertiary • Bronchioles – Branch off tertiary bronchi Bronchioles © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-13 Bronchial Tree (cont.) • Alveoli – Thin sacs of cells surrounded by capillaries – Secrete surfactant • Fatty substance • Helps maintains the inflation of the alveoli between inspirations © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-14 Lungs • Cone-shaped organs • Right lung – three lobes • Left lung – two lobes • Pleura – membranes surrounding the lungs The lungs contain connective tissue, the bronchial tree, nerves, lymphatic vessels, and blood vessels. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-15 Apply Your Knowledge Which of the following sites would be the most lethal if obstructed by a foreign body? ANSWER: a. Right bronchus b. Left bronchus c. Trachea © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-16 The Mechanisms of Breathing Inspiration Air rich in O2 enters the lungs from the atmosphere The diaphragm contracts or Expiration Air rich in C02 exits the lungs The diaphragm relaxes The intercostal muscles lower flattens The intercostal muscles raise the ribs the ribs Breathing, or pulmonary ventilation, consists of inspiration (inhalation) and expiration (exhalation). © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-17 The Mechanisms of Breathing (cont.) • Respiratory center of the brain • Other factors – CO2 levels in the blood – Medulla oblongata – controls rhythm and depth of breathing – pH of the blood – Pons – controls the rate of breathing – Inflation reflex – Fear and pain © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-18 The Mechanisms of Breathing (cont.) • Causes of altered breathing patterns – Coughing – Sneezing – Laughing – Crying – Hiccups – Yawning – Speaking © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-19 Apply Your Knowledge Indicated whether each statement refers to (I) inhalation or (E) exhalation: ANSWER: __ E The intercostal muscles lower the ribs I The diaphragm contracts or flattens __ I The intercostal muscles raise the ribs __ __ E The diaphragm relaxes I Air rich in O2 enters the lungs from the atmosphere __ E Air rich in C02 exits the lungs __ © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-20 The Transport of Oxygen and Carbon Dioxide in the Blood • Most of the oxygen binds to hemoglobin – Oxyhemoglobin – Bright red in color • Some oxygen remains dissolved in plasma • If CO2 combines with hemoglobin at O2 sites, it forms carboxyhemoglobin © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-21 The Transport of Oxygen and Carbon Dioxide in the Blood (cont.) • Carbon dioxide gets into the bloodstream – Reacts with water in plasma and forms carbonic acid – Carbonic acid ionizes and releases hydrogen and bicarbonate ions – Bicarbonate ions attach to hemoglobin • Exhaled as waste product in the lungs © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-22 Apply Your Knowledge Describe what happens to carbon dioxide in the blood. ANSWER: Carbon dioxide can combine with hemoglobin and form carboxyhemoglobin. Most reacts with water in plasma to form carbonic acid. The carbonic acid ionizes and releases hydrogen and bicarbonate ions. The bicarbonate ions then attach to hemoglobin and are exhaled as a waste product from the lungs. Super! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-23 Respiratory Volumes • Different volumes of air move in and out of lungs with different intensities of breathing • Measured to assess health of respiratory system © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-24 Respiratory Volumes (cont.) Tidal Volume Amount of air that moves in or out of the lungs during a normal breath Inspiratory Reserve Volume Amount of air that can be forcefully inhaled following a normal inhalation Expiratory Reserve Volume Amount of air that can be forcefully exhaled following a normal exhalation © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-25 Respiratory Volumes (cont.) Residual Volume Volume of air that always remains in the lungs even after a forceful exhalation Vital Capacity Amount of air that can be forcefully exhaled after the deepest inhalation possible Total Lung Capacity The total amount of air the lungs can hold © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-26 Apply Your Knowledge Match the following: ANSWER: C Amount of air that moves during ___ a normal breath B Amount of air that always ___ remains in the lungs A Total amount of air the lungs ___ can hold D Amount of air forcefully exhaled ___ after deepest inhalation possible A. Total lung capacity B. Residual volume C. Tidal volume D. Vital capacity Good Job! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-27 Snoring • • • Due to vibration of soft tissues when muscles of the palate, tongue, and throat relax Affects approximately 50% of men and 25% of women over the age of 40 Causes daytime sleepiness • Common Causes – Enlargement of tonsils or adenoids – Being overweight – Alcohol consumption – Nasal congestion – Deviated nasal septum – May be associated with obstructive sleep apnea © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-28 Snoring (cont.) Mayo Clinic’s Sleep Disorders Center rating of snoring: Heard from close proximity Heard from anywhere in the bedroom Heard from just outside the bedroom door with door open Heard outside the bedroom door with the door closed © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-29 Snoring (cont.) • Lifestyle modifications to reduce snoring – – – – – Lose weight Change sleeping position Avoid using alcohol or medications that induce sleep Use nasal strips to widen the nasal passages Use dental devices to keep airways open • Treatments – CPAP – Surgery (uvulotomy) – Laser surgery © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-30 Common Diseases and Disorders Disease Description Allergic rhinitis Hypersensitivity reaction to various airborne allergens Asthma A condition in which the tubes of the bronchial tree become obstructed due to inflammation Collapsed lung Atelectasis Bronchitis Inflammation of the bronchi often follows a cold; one type of COPD © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-31 Common Diseases and Disorders (cont.) Disease Description Chronic obstructive pulmonary disease (COPD) A group of lung disorders that limit airflow to lungs and usually cause enlargement of the alveoli Emphysema A chronic condition associated with smoking that damages the alveoli; one type of COPD Influenza A viral disease that attacks the respiratory system; commonly called the flu © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-32 Common Diseases and Disorders (cont.) Disease Description Laryngitis An acute inflammation of the larynx causing hoarseness (dysphonia) Legionnaire’s Acute bacterial pneumonia caused by disease Legionnaire bacteria that usually grows in the standing water of air conditioning systems Lung cancer Cancer closely associated with smoking and exposure to second-hand smoke; four types of lung cancers Pleural effusion A buildup of fluid in the pleural cavity © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-33 Common Diseases and Disorders (cont.) Disease Description Pleuritis/Pleurisy Inflammation of the membranes that cover the lungs, known as pleura Pneumoconiosis Pneumonia/ Pneumonitis Lung diseases that result from years environmental or occupational exposure to different types of dust; three types An inflammation of the lungs that is most often caused by a bacterial, viral, or fungal infection © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-34 Common Diseases and Disorders (cont.) Disease Description Pneumothorax A collection of air in the chest around the lungs, which may cause atelectasis Pulmonary edema A condition in which fluids fill spaces within the lungs, making it very difficult for the lungs to oxygenate the blood Pulmonary embolism A blood clot (embolism) that travels usually from the legs and blocks an artery in the lungs © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-35 Common Diseases and Disorders (cont.) Disease Description Respiratory distress syndrome (RDS) Syndrome in which a lack of surfactant in the lungs allows the alveoli to collapse on exhalation, resulting in poor oxygenation A viral respiratory disease that is very contagious and sometimes fatal Severe acute respiratory syndrome (SARS) Sinusitis An inflammation of the membranes lining the sinuses of the skull © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-36 Common Diseases and Disorders (cont.) Disease Sudden infant death syndrome (SIDS) Tuberculosis Description A syndrome without characteristic signs or symptoms; usually a baby with this disorder simply goes to sleep and never wakes up Primarily a respiratory disease caused by various strains of the bacterium Mycobacterium tuberculosis Upper respiratory Coryza, or the common cold (tract) infection (URI) © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-37 Apply Your Knowledge The medical assistant working for a general practitioner is taking the medical history of a new patient. The patient states, “Even after sleeping 8 to 9 hours, I still feel really tired.” The patient’s spouse states, “Well, you sure snore loud, as if the sleep is so good.” Which of the following is a possible cause for the excessive fatigue? ANSWER: a. Sleep apnea b. Depression c. Tuberculosis © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-38 In Summary 24.1 The function of the respiratory system is to move air in and out of the lungs in a process known as ventilation, respiration, or breathing. 24.2 The exchange of oxygen and carbon dioxide in the lungs is called external respiration. The same exchange within the hemoglobin of red blood cells is internal respiration. 24.3 The larynx contains the vocal cords, which stretch between the thyroid and cricoid cartilages. The muscles of the lower (true) vocal cords stretch and relax them to produce different sounds. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-39 In Summary (cont.) 24.4 The lungs contain connective tissue, the bronchial tree, nerves, lymphatic vessels, and blood vessels. The left lung consists of two lobes (upper and lower), and the right lung consists of three lobes (upper, middle, and lower). Within each lung are the primary, secondary, and tertiary branches of the bronchi, the bronchioles, and the alveoli. 24.5 The lungs are covered by, and the chest cavity is lined with, the pleura. The outer membrane is the parietal pleura and the inner membrane is the visceral pleura. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-40 In Summary (cont.) 24.6 During inspiration, the diaphragm contracts and the intercostal muscles raise the ribs, increasing the space in the thoracic cavity. This decreases the pressure within the cavity so that the air outside the body passively flows into the thoracic cavity. During expiration, the diaphragm relaxes, pushing up into the thoracic cavity, and the intercostal muscles lower the ribs, forcing the air to flow out of the body. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-41 In Summary (cont.) 24.7 Breathing is controlled by the respiratory center of the brain located in the pons and medulla oblongata. Carbon dioxide levels and pH levels of the blood also affect breathing. Everyday situations such as coughing, sneezing, laughing, crying, hiccups, yawning, and speaking also alter breathing patterns. 24.8 Most of the oxygen in the bloodstream binds to the hemoglobin within red blood cells, resulting in oxyhemoglobin, although a small amount does not bind to hemoglobin and remains dissolved in the plasma. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-42 In Summary (cont.) 24.9 Carbon dioxide binds to hemoglobin, resulting in carboxyhemoglobin. Most of the carbon dioxide that enters the body reacts with water in blood and cerebral spinal fluid to form carbonic acid. As carbonic acid ionizes, it releases hydrogen and bicarbonate ions, which attach to hemoglobin making its way back to the lungs to be exhaled. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-43 In Summary (cont.) 24.10 Respiratory volumes are measured to check the health of the respiratory system. The volumes are listed here and the normal capacities are found in the chapter: tidal volume, inspiratory and expiratory reserve volumes, residual volume, inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-44 In Summary (cont.) 24.11 The diseases and disorders of the respiratory system are many and varied, as are the causes and treatments of these diseases. Many of the more common respiratory disorders, with their individual causes and treatments, are discussed in detail in the Pathophysiology section of this chapter. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 24-45 End of Chapter 24 The air of ideas is the only air worth breathing. ~Edith Wharton © 2011 The McGraw-Hill Companies, Inc. All rights reserved.