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Key Terms Chapter 22: The Respiratory System

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    62674
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    acclimatization
    process 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 cartilage
    cartilage 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 space
    air space within alveoli that are unable to participate in gas exchange
    alveolar duct
    small tube that leads from the terminal bronchiole to the respiratory bronchiole and is the point of attachment for alveoli
    alveolar macrophage
    immune system cell of the alveolus that removes debris and pathogens
    alveolar pore
    opening that allows airflow between neighboring alveoli
    alveolar sac
    cluster of alveoli
    alveolus
    small, grape-like sac that performs gas exchange in the lungs
    anatomical dead space
    air space present in the airway that never reaches the alveoli and therefore never participates in gas exchange
    apex
    tip of the external nose
    apneustic center
    network of neurons within the pons that stimulate the neurons in the dorsal respiratory group; controls the depth of inspiration
    atmospheric pressure
    amount of force that is exerted by gases in the air surrounding any given surface
    Bohr effect
    relationship between blood pH and oxygen dissociation from hemoglobin
    Boyle’s law
    relationship between volume and pressure as described by the formula: P1V1 = P2V2
    bridge
    portion of the external nose that lies in the area of the nasal bones
    bronchial bud
    structure in the developing embryo that forms when the laryngotracheal bud extends and branches to form two bulbous structures
    bronchial tree
    collective name for the multiple branches of the bronchi and bronchioles of the respiratory system
    bronchiole
    branch of bronchi that are 1 mm or less in diameter and terminate at alveolar sacs
    bronchoconstriction
    decrease in the size of the bronchiole due to relaxation of the muscular wall
    bronchodilation
    increase in the size of the bronchiole due to contraction of the muscular wall
    bronchus
    tube connected to the trachea that branches into many subsidiaries and provides a passageway for air to enter and leave the lungs
    carbaminohemoglobin
    bound 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 notch
    indentation on the surface of the left lung that allows space for the heart
    central chemoreceptor
    one 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 shift
    facilitated diffusion that exchanges bicarbonate (HCO3) with chloride (Cl) ions
    conducting zone
    region of the respiratory system that includes the organs and structures that provide passageways for air and are not directly involved in gas exchange
    cricoid cartilage
    portion 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 law
    statement 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 nasi
    intermediate portion of the external nose that connects the bridge to the apex and is supported by the nasal bone
    epiglottis
    leaf-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 nose
    region of the nose that is easily visible to others
    external respiration
    gas exchange that occurs in the alveoli
    fauces
    portion of the posterior oral cavity that connects the oral cavity to the oropharynx
    fibroelastic membrane
    specialized 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
    foregut
    endoderm 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
    glottis
    opening between the vocal folds through which air passes when producing speech
    Haldane effect
    relationship between the partial pressure of oxygen and the affinity of hemoglobin for carbon dioxide
    Henry’s law
    statement of the principle that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas
    hilum
    concave structure on the mediastinal surface of the lungs where blood vessels, lymphatic vessels, nerves, and a bronchus enter the lung
    hyperpnea
    increased rate and depth of ventilation due to an increase in oxygen demand that does not significantly alter blood oxygen or carbon dioxide levels
    hyperventilation
    increased 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 respiration
    gas exchange that occurs at the level of body tissues
    intra-alveolar pressure
    (intrapulmonary pressure) pressure of the air within the alveoli
    intrapleural pressure
    pressure of the air within the pleural cavity
    laryngeal prominence
    region where the two lamine of the thyroid cartilage join, forming a protrusion known as “Adam’s apple”
    laryngopharynx
    portion of the pharynx bordered by the oropharynx superiorly and esophagus and trachea inferiorly; serves as a route for both air and food
    laryngotracheal
    bud forms from the lung bud, has a tracheal end and bulbous bronchial buds at the distal end
    larynx
    cartilaginous 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 tonsil
    lymphoid tissue located at the base of the tongue
    lung
    organ of the respiratory system that performs gas exchange
    lung bud
    median dome that forms from the endoderm of the foregut
    meatus
    one 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 bone
    bone of the skull that lies under the root and bridge of the nose and is connected to the frontal and maxillary bones
    nasal septum
    wall composed of bone and cartilage that separates the left and right nasal cavities
    nasopharynx
    portion of the pharynx flanked by the conchae and oropharynx that serves as an airway
    olfactory pit
    invaginated ectodermal tissue in the anterior portion of the head region of an embryo that will form the nasal cavity
    oropharynx
    portion of the pharynx flanked by the nasopharynx, oral cavity, and laryngopharynx that is a passageway for both air and food
    oxygen–hemoglobin dissociation curve
    graph 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 tonsil
    one of the paired structures composed of lymphoid tissue located anterior to the uvula at the roof of isthmus of the fauces
    paranasal sinus
    one 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 pleura
    outermost layer of the pleura that connects to the thoracic wall, mediastinum, and diaphragm
    partial pressure
    force exerted by each gas in a mixture of gases
    peripheral chemoreceptor
    one of the specialized receptors located in the aortic arch and carotid arteries that sense changes in pH, carbon dioxide, or oxygen blood levels
    pharyngeal tonsil
    structure composed of lymphoid tissue located in the nasopharynx
    pharynx
    region 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
    philtrum
    concave surface of the face that connects the apex of the nose to the top lip
    pleural cavity
    space between the visceral and parietal pleurae
    pleural fluid
    substance that acts as a lubricant for the visceral and parietal layers of the pleura during the movement of breathing
    pneumotaxic center
    network of neurons within the pons that inhibit the activity of the neurons in the dorsal respiratory group; controls rate of breathing
    pulmonary artery
    artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli
    pulmonary plexus
    network of autonomic nervous system fibers found near the hilum of the lung
    pulmonary surfactant
    substance composed of phospholipids and proteins that reduces the surface tension of the alveoli; made by type II alveolar cells
    pulmonary ventilation
    exchange 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 bronchiole
    specific type of bronchiole that leads to alveolar sacs
    respiratory cycle
    one sequence of inspiration and expiration
    respiratory epithelium
    ciliated lining of much of the conducting zone that is specialized to remove debris and pathogens, and produce mucus
    respiratory membrane
    alveolar and capillary wall together, which form an air-blood barrier that facilitates the simple diffusion of gases
    respiratory rate
    total number of breaths taken each minute
    respiratory volume
    varying amounts of air within the lung at a given time
    respiratory zone
    includes structures of the respiratory system that are directly involved in gas exchange
    root
    region of the external nose between the eyebrows
    thoracic wall compliance
    ability of the thoracic wall to stretch while under pressure
    thyroid cartilage
    largest 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 space
    sum 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 pressure
    sum of all the partial pressures of a gaseous mixture
    trachea
    tube 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 muscle
    smooth muscle located in the fibroelastic membrane of the trachea
    transpulmonary pressure
    pressure difference between the intrapleural and intra-alveolar pressures
    true vocal cord
    one 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 cell
    squamous epithelial cells that are the major cell type in the alveolar wall; highly permeable to gases
    type II alveolar cell
    cuboidal epithelial cells that are the minor cell type in the alveolar wall; secrete pulmonary surfactant
    ventilation
    movement 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 fold
    part of the folded region of the glottis composed of mucous membrane; supports the epiglottis during swallowing
    visceral pleura
    innermost 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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