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22.9: Key Terms

  • Page ID
    69374
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    Example and Directions
    Words (or words that have the same definition)The definition is case sensitive(Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages](Optional) Caption for Image(Optional) External or Internal Link(Optional) Source for Definition
    (Eg. "Genetic, Hereditary, DNA ...")(Eg. "Relating to genes or heredity")The infamous double helix https://bio.libretexts.org/CC-BY-SA; Delmar Larsen
    Glossary Entries
    Word(s)DefinitionImageCaptionLinkSource
    acclimatizationprocess of adjustment that the respiratory system makes due to chronic exposure to high altitudes    
    acute mountain sickness (AMS)condition that occurs a result of acute exposure to high altitude due to a low partial pressure of oxygen    
    ala(plural = alae) small, flaring structure of a nostril that forms the lateral side of the nares    
    alar cartilagecartilage that supports the apex of the nose and helps shape the nares; it is connected to the septal cartilage and connective tissue of the alae    
    alveolar dead spaceair space within alveoli that are unable to participate in gas exchange    
    alveolar ductsmall tube that leads from the terminal bronchiole to the respiratory bronchiole and is the point of attachment for alveoli    
    alveolar macrophageimmune system cell of the alveolus that removes debris and pathogens    
    alveolar poreopening that allows airflow between neighboring alveoli    
    alveolar saccluster of alveoli    
    alveolussmall, grape-like sac that performs gas exchange in the lungs    
    anatomical dead spaceair space present in the airway that never reaches the alveoli and therefore never participates in gas exchange    
    apextip of the external nose    
    apneustic centernetwork of neurons within the pons that stimulate the neurons in the dorsal respiratory group; controls the depth of inspiration    
    atmospheric pressureamount of force that is exerted by gases in the air surrounding any given surface    
    Bohr effectrelationship between blood pH and oxygen dissociation from hemoglobin    
    Boyle’s lawrelationship between volume and pressure as described by the formula: P1V1 = P2V2    
    bridgeportion of the external nose that lies in the area of the nasal bones    
    bronchial budstructure in the developing embryo that forms when the laryngotracheal bud extends and branches to form two bulbous structures    
    bronchial treecollective name for the multiple branches of the bronchi and bronchioles of the respiratory system    
    bronchiolebranch of bronchi that are 1 mm or less in diameter and terminate at alveolar sacs    
    bronchoconstrictiondecrease in the size of the bronchiole due to relaxation of the muscular wall    
    bronchodilationincrease in the size of the bronchiole due to contraction of the muscular wall    
    bronchustube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs    
    carbaminohemoglobinbound form of hemoglobin and carbon dioxide    
    carbonic anhydrase (CA)enzyme that catalyzes the reaction that causes carbon dioxide and water to form carbonic acid    
    cardiac notchindentation on the surface of the left lung that allows space for the heart    
    central chemoreceptorone of the specialized receptors that are located in the brain that sense changes in hydrogen ion, oxygen, or carbon dioxide concentrations in the brain    
    chloride shiftfacilitated diffusion that exchanges bicarbonate (HCO3) with chloride (Cl) ions    
    conducting zoneregion of the respiratory system that includes the organs and structures that provide passageways for air and are not directly involved in gas exchange    
    cricoid cartilageportion of the larynx composed of a ring of cartilage with a wide posterior region and a thinner anterior region; attached to the esophagus    
    Dalton’s lawstatement of the principle that a specific gas type in a mixture exerts its own pressure, as if that specific gas type was not part of a mixture of gases    
    dorsal respiratory group (DRG)region of the medulla oblongata that stimulates the contraction of the diaphragm and intercostal muscles to induce inspiration    
    dorsum nasiintermediate portion of the external nose that connects the bridge to the apex and is supported by the nasal bone    
    epiglottisleaf-shaped piece of elastic cartilage that is a portion of the larynx that swings to close the trachea during swallowing    
    expiration(also, exhalation) process that causes the air to leave the lungs    
    expiratory reserve volume (ERV)amount of air that can be forcefully exhaled after a normal tidal exhalation    
    external noseregion of the nose that is easily visible to others    
    external respirationgas exchange that occurs in the alveoli    
    faucesportion of the posterior oral cavity that connects the oral cavity to the oropharynx    
    fibroelastic membranespecialized membrane that connects the ends of the C-shape cartilage in the trachea; contains smooth muscle fibers    
    forced breathing(also, hyperpnea) mode of breathing that occurs during exercise or by active thought that requires muscle contraction for both inspiration and expiration    
    foregutendoderm of the embryo towards the head region    
    functional residual capacity (FRC)sum of ERV and RV, which is the amount of air that remains in the lungs after a tidal expiration    
    glottisopening between the vocal folds through which air passes when producing speech    
    Haldane effectrelationship between the partial pressure of oxygen and the affinity of hemoglobin for carbon dioxide    
    Henry’s lawstatement of the principle that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas    
    hilumconcave structure on the mediastinal surface of the lungs where blood vessels, lymphatic vessels, nerves, and a bronchus enter the lung    
    hyperpneaincreased rate and depth of ventilation due to an increase in oxygen demand that does not significantly alter blood oxygen or carbon dioxide levels    
    hyperventilationincreased ventilation rate that leads to abnormally low blood carbon dioxide levels and high (alkaline) blood pH    
    inspiration(also, inhalation) process that causes air to enter the lungs    
    inspiratory capacity (IC)sum of the TV and IRV, which is the amount of air that can maximally be inhaled past a tidal expiration    
    inspiratory reserve volume (IRV)amount of air that enters the lungs due to deep inhalation past the tidal volume    
    internal respirationgas exchange that occurs at the level of body tissues    
    intra-alveolar pressure(intrapulmonary pressure) pressure of the air within the alveoli    
    intrapleural pressurepressure of the air within the pleural cavity    
    laryngeal prominenceregion where the two lamine of the thyroid cartilage join, forming a protrusion known as “Adam’s apple”    
    laryngopharynxportion of the pharynx bordered by the oropharynx superiorly and esophagus and trachea inferiorly; serves as a route for both air and food    
    laryngotrachealbud forms from the lung bud, has a tracheal end and bulbous bronchial buds at the distal end    
    larynxcartilaginous structure that produces the voice, prevents food and beverages from entering the trachea, and regulates the volume of air that enters and leaves the lungs    
    lingual tonsillymphoid tissue located at the base of the tongue    
    lungorgan of the respiratory system that performs gas exchange    
    lung budmedian dome that forms from the endoderm of the foregut    
    meatusone of three recesses (superior, middle, and inferior) in the nasal cavity attached to the conchae that increase the surface area of the nasal cavity    
    naris(plural = nares) opening of the nostrils    
    nasal bonebone of the skull that lies under the root and bridge of the nose and is connected to the frontal and maxillary bones    
    nasal septumwall composed of bone and cartilage that separates the left and right nasal cavities    
    nasopharynxportion of the pharynx flanked by the conchae and oropharynx that serves as an airway    
    olfactory pitinvaginated ectodermal tissue in the anterior portion of the head region of an embryo that will form the nasal cavity    
    oropharynxportion of the pharynx flanked by the nasopharynx, oral cavity, and laryngopharynx that is a passageway for both air and food    
    oxygen–hemoglobin dissociation curvegraph that describes the relationship of partial pressure to the binding and disassociation of oxygen to and from heme    
    oxyhemoglobin(Hb–O2) bound form of hemoglobin and oxygen    
    palatine tonsilone of the paired structures composed of lymphoid tissue located anterior to the uvula at the roof of isthmus of the fauces    
    paranasal sinusone of the cavities within the skull that is connected to the conchae that serve to warm and humidify incoming air, produce mucus, and lighten the weight of the skull; consists of frontal, maxillary, sphenoidal, and ethmoidal sinuses    
    parietal pleuraoutermost layer of the pleura that connects to the thoracic wall, mediastinum, and diaphragm    
    partial pressureforce exerted by each gas in a mixture of gases    
    peripheral chemoreceptorone of the specialized receptors located in the aortic arch and carotid arteries that sense changes in pH, carbon dioxide, or oxygen blood levels    
    pharyngeal tonsilstructure composed of lymphoid tissue located in the nasopharynx    
    pharynxregion of the conducting zone that forms a tube of skeletal muscle lined with respiratory epithelium; located between the nasal conchae and the esophagus and trachea    
    philtrumconcave surface of the face that connects the apex of the nose to the top lip    
    pleural cavityspace between the visceral and parietal pleurae    
    pleural fluidsubstance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing    
    pneumotaxic centernetwork of neurons within the pons that inhibit the activity of the neurons in the dorsal respiratory group; controls rate of breathing    
    pulmonary arteryartery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli    
    pulmonary plexusnetwork of autonomic nervous system fibers found near the hilum of the lung    
    pulmonary surfactantsubstance composed of phospholipids and proteins that reduces the surface tension of the alveoli; made by type II alveolar cells    
    pulmonary ventilationexchange of gases between the lungs and the atmosphere; breathing    
    quiet breathing(also, eupnea) mode of breathing that occurs at rest and does not require the cognitive thought of the individual    
    residual volume (RV)amount of air that remains in the lungs after maximum exhalation    
    respiratory bronchiolespecific type of bronchiole that leads to alveolar sacs    
    respiratory cycleone sequence of inspiration and expiration    
    respiratory epitheliumciliated lining of much of the conducting zone that is specialized to remove debris and pathogens, and produce mucus    
    respiratory membranealveolar and capillary wall together, which form an air-blood barrier that facilitates the simple diffusion of gases    
    respiratory ratetotal number of breaths taken each minute    
    respiratory volumevarying amounts of air within the lung at a given time    
    respiratory zoneincludes structures of the respiratory system that are directly involved in gas exchange    
    rootregion of the external nose between the eyebrows    
    thoracic wall complianceability of the thoracic wall to stretch while under pressure    
    thyroid cartilagelargest piece of cartilage that makes up the larynx and consists of two lamine    
    tidal volume (TV)amount of air that normally enters the lungs during quiet breathing    
    total dead spacesum of the anatomical dead space and alveolar dead space    
    total lung capacity (TLC)total amount of air that can be held in the lungs; sum of TV, ERV, IRV, and RV    
    total pressuresum of all the partial pressures of a gaseous mixture    
    tracheatube composed of cartilaginous rings and supporting tissue that connects the lung bronchi and the larynx; provides a route for air to enter and exit the lung    
    trachealis musclesmooth muscle located in the fibroelastic membrane of the trachea    
    transpulmonary pressurepressure difference between the intrapleural and intra-alveolar pressures    
    true vocal cordone of the pair of folded, white membranes that have a free inner edge that oscillates as air passes through to produce sound    
    type I alveolar cellsquamous epithelial cells that are the major cell type in the alveolar wall; highly permeable to gases    
    type II alveolar cellcuboidal epithelial cells that are the minor cell type in the alveolar wall; secrete pulmonary surfactant    
    ventilationmovement of air into and out of the lungs; consists of inspiration and expiration    
    ventral respiratory group (VRG)region of the medulla oblongata that stimulates the contraction of the accessory muscles involved in respiration to induce forced inspiration and expiration    
    vestibular foldpart of the folded region of the glottis composed of mucous membrane; supports the epiglottis during swallowing    
    visceral pleurainnermost layer of the pleura that is superficial to the lungs and extends into the lung fissures    
    vital capacity (VC)sum of TV, ERV, and IRV, which is all the volumes that participate in gas exchange    

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