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7.7.6: Key Terms

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    alveolar P O 2 P O 2
    partial pressure of oxygen in the alveoli (usually around 100 mmHg)
    alveolar duct
    duct that extends from the terminal bronchiole to the alveolar sac
    alveolar sac
    structure consisting of two or more alveoli that share a common opening
    alveolar ventilation
    how much air is in the alveoli
    (plural: alveoli) (also, air sac) terminal region of the lung where gas exchange occurs
    anatomical dead space
    (also, anatomical shunt) region of the lung that lacks proper ventilation/perfusion due to an anatomical block
    bicarbonate (HCO 3 ) (HCO 3 ) ion
    ion created when carbonic acid dissociates into H+ and (HCO 3 ) (HCO 3 )
    bicarbonate buffer system
    system in the blood that absorbs carbon dioxide and regulates pH levels
    airway that extends from the main tertiary bronchi to the alveolar sac
    (plural: bronchi) smaller branch of cartilaginous tissue that stems off of the trachea; air is funneled through the bronchi to the region where gas exchange occurs in alveoli
    molecule that forms when carbon dioxide binds to hemoglobin
    carbonic anhydrase (CA)
    enzyme that catalyzes carbon dioxide and water into carbonic acid
    chloride shift
    exchange of chloride for bicarbonate into or out of the red blood cell
    measurement of the elasticity of the lung
    dead space
    area in the lung that lacks proper ventilation or perfusion
    domed-shaped skeletal muscle located under lungs that separates the thoracic cavity from the abdominal cavity
    elastic recoil
    property of the lung that drives the lung tissue inward
    elastic work
    work conducted by the intercostal muscles, chest wall, and diaphragm
    expiratory reserve volume (ERV)
    amount of additional air that can be exhaled after a normal exhalation
    FEV1/FVC ratio
    ratio of how much air can be forced out of the lung in one second to the total amount that is forced out of the lung; a measurement of lung function that can be used to detect disease states
    work of breathing performed by the alveoli and tissues in the lung
    forced expiratory volume (FEV)
    (also, forced vital capacity) measure of how much air can be forced out of the lung from maximal inspiration over a specific amount of time
    functional residual capacity (FRC)
    expiratory reserve volume plus residual volume
    functional vital capacity (FVC)
    amount of air that can be forcibly exhaled after taking the deepest breath possible
    heme group
    centralized iron-containing group that is surrounded by the alpha and beta subunits of hemoglobin
    molecule in red blood cells that can bind oxygen, carbon dioxide, and carbon monoxide
    inspiratory capacity (IC)
    tidal volume plus inspiratory reserve volume
    inspiratory reserve volume (IRV)
    amount of additional air that can be inspired after a normal inhalation
    intercostal muscle
    muscle connected to the rib cage that contracts upon inspiration
    intrapleural space
    space between the layers of pleura
    voice box, a short passageway connecting the pharynx and the trachea
    lung capacity
    measurement of two or more lung volumes (how much air can be inhaled from the end of an expiration to maximal capacity)
    lung volume
    measurement of air for one lung function (normal inhalation or exhalation)
    complex glycoprotein found in mucus
    sticky protein-containing fluid secretion in the lung that traps particulate matter to be expelled from the body
    nasal cavity
    opening of the respiratory system to the outside environment
    obstructive disease
    disease (such as emphysema and asthma) that arises from obstruction of the airways; compliance increases in these diseases
    oxygen dissociation curve
    curve depicting the affinity of oxygen for hemoglobin
    oxygen-carrying capacity
    amount of oxygen that can be transported in the blood
    partial pressure
    amount of pressure exerted by one gas within a mixture of gases
    particulate matter
    small particle such as dust, dirt, viral particles, and bacteria that are in the air
    throat; a tube that starts in the internal nares and runs partway down the neck, where it opens into the esophagus and the larynx
    physiological dead space
    (also, physiological shunt) region of the lung that lacks proper ventilation/perfusion due to a physiological change in the lung (like inflammation or edema)
    tissue layer that surrounds the lungs and lines the interior of the thoracic cavity
    painful inflammation of the pleural tissue layers
    primary bronchus
    (also, main bronchus) region of the airway within the lung that attaches to the trachea and bifurcates to each lung where it branches into secondary bronchi
    process of opening airways that normally remain closed when the cardiac output increases
    residual volume (RV)
    amount of air remaining in the lung after a maximal expiration
    measurement of lung obstruction
    respiratory bronchiole
    terminal portion of the bronchiole tree that is attached to the terminal bronchioles and alveoli ducts, alveolar sacs, and alveoli
    respiratory distress syndrome
    disease that arises from a deficient amount of surfactant
    respiratory quotient (RQ)
    ratio of carbon dioxide production to each oxygen molecule consumed
    respiratory rate
    number of breaths per minute
    restrictive disease
    disease that results from a restriction and decreased compliance of the alveoli; respiratory distress syndrome and pulmonary fibrosis are examples
    sickle cell anemia
    genetic disorder that affects the shape of red blood cells, and their ability to transport oxygen and move through capillaries
    method to measure lung volumes and to diagnose lung diseases
    detergent-like liquid in the airways that lowers the surface tension of the alveoli to allow for expansion
    terminal bronchiole
    region of bronchiole that attaches to the respiratory bronchioles
    rare genetic disorder that results in mutation of the alpha or beta subunits of hemoglobin, creating smaller red blood cells with less hemoglobin
    tidal volume (TV)
    amount of air that is inspired and expired during normal breathing
    total lung capacity (TLC)
    sum of the residual volume, expiratory reserve volume, tidal volume, and inspiratory reserve volume
    cartilaginous tube that transports air from the larynx to the primary bronchi
    venous P CO 2 P CO 2
    partial pressure of carbon dioxide in the veins (40 mm Hg in the pulmonary veins)
    venous P O 2 P O 2
    partial pressure of oxygen in the veins (100 mm Hg in the pulmonary veins)
    ventilation/perfusion (V/Q) mismatch
    region of the lung that lacks proper alveolar ventilation (V) and/or arterial perfusion (Q)
    vital capacity (VC)
    sum of the expiratory reserve volume, tidal volume, and inspiratory reserve volume

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