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Memmler’s Structure and Function of the Human Body 9th edition Chapter 16 The Respiratory System Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Phases of Respiration Process of obtaining oxygen from environment and delivering it to cells • Pulmonary ventilation • External exchange of gases • Internal exchange of gases Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Overview of respiration. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-1: What are the three phases of respiration? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Respiratory System Conducts air into lungs • Nasal cavities • Pharynx • Larynx • Trachea (windpipe) • Bronchi Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The respiratory system. (A) Overview. (B) Enlarged section of lung tissue showing the relationship between the alveoli (air sacs) of the lungs and the blood capillaries. (C) A transverse section through the lungs. Zooming In: What organ is located in the medial depression of the left lung? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: True or False?: The two gases involved in the external exchange of gases that takes place in the respiratory system are CO2 and O2. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: True: The two gases involved in the external exchange of gases that takes place in the respiratory system are CO2 and O2. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Nasal Cavities • Nostrils (nares) • Nasal cavities – Mucous membrane • Filters foreign bodies • Warms air • Moistens air – Conchae • Nasal septum • Sinuses Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-2: What happens to air as it passes over the nasal mucosa? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Pharynx Throat (pharynx) carries air to respiratory tract and food to digestive system • Nasopharynx – Superior portion • Oropharynx – Middle portion • Laryngeal pharynx – Inferior portion Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Larynx Larynx (voice box) is located between the pharynx and trachea • Cartilage framework – Thyroid cartilage (Adam’s apple) • Vocal folds (vocal cords) – Used for speech • Glottis • Epiglottis Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The larynx. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The vocal cords, superior view. ZOOMING IN • What cartilage is named for its position above the glottis? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Trachea Trachea (wind pipe) conducts air between larynx and lungs • Framework of separate cartilages • Horseshoe shaped • Open at back for expansion during swallowing Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-3: What are the scientific names for the throat, voice box, and windpipe? Checkpoint 16-4: What are the three regions of the pharynx? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Bronchi • Trachea divides into two primary bronchi that enter • the lungs • Hilum • Epithelial tissue lining – Pseudostratified – Cilia Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Microscopic view of ciliated epithelium. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-5: The cells that line the respiratory passageways help to keep impurities out of the lungs. What feature of these cells enables them to filter impurities and move fluids? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: The air-conducting passageways of the respiratory tract are lined with what type of tissue? a. stratified squamous epithelial b. pseudostratified epithelial c. squamous epithelial Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: b. pseudostratified epithelial Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Lungs • Mediastinum • Lobes – Bronchial tree – Bronchioles • Alveoli • Diaphragm • Pleura – Parietal pleura – Visceral pleura – Pleural space Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Lung tissue viewed through a microscope. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-6: In what structures does gas exchange occur in the lung? Checkpoint 16-7: What is the name of the membrane that encloses the lung? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Process of Respiration • Ventilation of lungs • Exchange of gases • Transport of gases in blood Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Pulmonary Ventilation • Inhalation (inspiration) is active phase – Compliance • Exhalation (expiration) is passive phase • Lung capacity Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Pulmonary ventilation. (A)Inhalation. (B)Exhalation. Zooming In: What muscles are located between the ribs? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-8: What are the two phases of breathing? Which is active and which is passive? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Gas Exchange • Diffusion is movement of molecules from higher to lower concentration • External exchange – Gases move between alveoli and capillary blood • Internal exchange – Gases move between blood and tissues Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Gas exchange. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-9: Gases move between the alveoli and the blood by the process of diffusion. What is the definition of diffusion? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Transport of Oxygen • Most oxygen in capillary blood binds to hemoglobin • Oxygen must separate from hemoglobin to enter cells Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-10: What substance in red blood cells carries almost all of the oxygen in the blood? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Transport of Carbon Dioxide • 10% is dissolved in plasma and fluid in red blood cells • 15% is combined with protein of hemoglobin and plasma proteins • 75% dissolves in blood fluids and is converted to bicarbonate ion – First combines with water to form carbonic acid – Carbonic acid ionizes (separates) into hydrogen and bicarbonate ions – Carbonic anhydrase enzyme speeds conversion – Buffers blood to keep pH steady Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-11: What is the main form in which carbon dioxide is carried in the blood? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: In what structure of the respiratory system does most gas exchange take place? a. bronchioles b. pleurae c. alveoli Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: c. alveoli Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Regulation of Respiration Fundamental respiratory pattern • Controlled by central nervous system centers – Partly in medulla (main control center), partly in pons (modifies patterns set in the medulla) • Modified by receptors detecting changes in blood chemistry Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Nervous Control • Control center is located in medulla and pons of brain stem • Motor nerve fibers extend into spinal cord • Fibers extend through phrenic nerve to diaphragm Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-12: What part of the brain stem sets the basic pattern of respiration? Checkpoint 16-13: What is the name of the motor nerve that controls the diaphragm? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chemical Control • Central chemoreceptors – Located near medullary respiratory center – Respond to raised CO2 level (hypercapnia) • Peripheral chemoreceptors – Located in neck and aortic arch – Respond to oxygen level considerably below normal Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 16-14: What gas is the main chemical controller of respiration? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Abnormal Ventilation • Hyperventilation – High oxygen level and low CO2 level (hypocapnia) – Increases blood pH • Hypoventilation – Insufficient air in alveoli – Decreases blood pH Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Breathing Patterns • Measured in breaths per minute • Adults: 12 to 20 • Children: 20 to 40 • Infants: more than 40 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Some Terms for Altered Breathing • Hyperpnea • Hypopnea • Tachypnea • Apnea • Dyspnea • Orthopnea • Kussmaul respiration • Cheyne-Stokes respiration Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: What is the medical term for temporary cessation of breathing? a. dyspnea b. apnea c. hypopnea Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: b. apnea Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Results of Inadequate Breathing • Cyanosis • Hypoxia • Hypoxemia • Suffocation Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Age and the Respiratory Tract • Tissues lose elasticity, become more rigid • Decreased compliance, lung capacity • Increased susceptibility to infection • Increased incidence of emphysema • Reduced capacity for exercise Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins End of Presentation Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins