Term
| conducting portion of respiratory system |
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Definition
| starts at the nose and includes the nasal cavity and the paranasal sinuses, nasopharynx, oropharynx, larynx, trachea, bronchi, bronchioles, up to the terminal bronchioles |
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Term
| respiratory portion of respiratory system |
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Definition
| made up of respiratory bronchioles, alveolar ducts,alveolar sacs and the alveoli |
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Term
| function of the respiratory system |
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Definition
| 1. bringing air to the respiratory zone and obtaining oxygen from the air; 2. removal of carbon dioxide important in acid-base balance; 3. air is modified and filtered to remove pathogens; 4.expiration important in phonation |
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Term
| nasal cavity, nasal pharynx, and larynx |
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Definition
| lined by a respiratory epithelium; made up of pseudostratified ciliated columnar epithelium with goblet cells |
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Term
| role of ciliated cells in respiratory system |
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Definition
| move airborne pathogens away from the respiratory zone |
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Term
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Definition
| secrete mucous to humidify air and trap airborne pathogens |
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Term
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Definition
| contains a rich capillary network that run perpendicular to flow of air important for heat exchange |
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Term
| presentation of virus or allergen in lamina propria |
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Definition
| rich capillaries become leaky upon the presentation of these pathogens causing accumulation of mast cells which make capillary bed leaky and cause it fill with fluid-becoming congested |
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Term
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Definition
| starts with trachea and has 23 generations of branches and ends with 8*10^6 alveolar sacs |
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Term
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Definition
| consists of 1. muscosa includes pseudostratified ciliated columnar epithelium with Goblet cells and lamina propria (with elastic fibers); 2. submucosa contains denser connective tissue and glands; 3. also has C-shaped ring of hyaline cartilage with ends connected by smooth muscle; 4. adventitia surround the outside of the trachea |
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Term
| characteristic of pseudostratified ciliated columnar epithelium |
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Definition
| consists of ciliated cells, mucous (Goblet) cells, brush cells, small granule cells and basal cells; ciliated cells span length of epithelium |
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Term
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Definition
| receptors that contact and afferent nerve ending act as sensory receptor of tracheal mucosa |
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Term
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Definition
| function is poorly understood in respiratory system |
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Term
| basement membrane of trachea |
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Definition
| consists of basal lamina, reticular lamina, and densely packed collagen fibers; deep to this layer is lamina propria which is seperated to the submucosa by elastic fibers |
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Term
| bronchus associated lympathatic tissue (BALT) |
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Definition
| consists of diffuse accumulations of lymphatic tissue as well as nodular lympathatic tissue |
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Term
| metaplasia of conducting portion of bronchial tree |
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Definition
| caused by irritation of the airway by particulate matter and causes loss of cilia motility; particulates are then moved up by coughing which irritates mucosa further and replaced by stratified squamous epithelium |
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Term
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Definition
| left and right divided by trachea; left divides into 2 lobar branches and 8 bronchopulmonary segments; right divides into 3 lobar bronchial branches subdivide into 10 bronchopulmonary segments |
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Term
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Definition
| 1. mucosa made up of pseudostratified ciliated columnar epithelium with goblet cells; 2. smooth muscle muscularis layer; 3. submucosa has serous secreting glands; 4. deep to submucosa is region of bronchus with cartilaginous plates rather than a ring; 5. adventitia surrounds the bronchus |
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Term
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Definition
| 12 generations that end conducting portion of respiratory system; no longer have glands; cartilaginous plates end in bronchial segments; few if any goblet cells and changes from pseudostratified ciliated columnar to columnar epithelium to cubodial epithelium; smooth muscle, collagenous fibers, and elastic tissue found beneath epithelium; lymphocytes, mast cells, and plasma cells are also found in CT |
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Term
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Definition
| replace goblet cells in terminal bronchioles; active secretory cells that secrete lipoprotein similar to surfactant prevent adhesion of bronchiole wall to itself during expiration |
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Term
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Definition
| first segment to have alveolar outpocketing and gaseous exchange; has simple cubodial epithelium occasionally has cilia; have elastic fibers, smooth muscle and lympathtic tissue; smooth muscle is innervated by parasympathetic nervous system |
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Term
| terminal end of the airway |
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Definition
| respiratory bronchiole continues as alveolar duct open into alveolar sacs |
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Term
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Definition
| walls are made up of type 1 and type 2 alveolar cells; macrophages found in CT and air spaces; within interstitium are elastic and reticular fibers (recoil is important for respiration) |
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Term
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Definition
| simple squamous cells that appose capillaries maintain air-blood barrier for exhange of O2 and CO2 by passive diffusion |
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Term
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Definition
| produce surfactant to reduce surface tension of the alveoli consists of DPPC |
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Term
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Definition
| interconnections between alveoli; permit air to circulate between alveoli |
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Term
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Definition
| develops caudal to larynx; epithelium develops from the endoderm and tracheal cartilage and muscles develop from splanchnic mesoderm |
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Term
| phases of lung development |
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Definition
| 1. pseudoglandular period-bronchi are dividing into smaller and smaller units (2-4 month); 2. canalicular period-next 2 and 1/2 months respiratory bronchioles are formed; 3. 7th month to birth terminal sac phase where number of capillaries increase and and capillaries approach the respiratory epithelium-formation of squamous epithelium from type I cells; 4. alveolar period from 8th month on where mature alveoli continue to form with increase in SA |
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Term
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Definition
| 1. quiet breathing-0.5-1.0 L/sec; 2. exercise or forced expiration: 7-10 L/sec |
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Term
| diffusion of respiratory gases |
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Definition
| moves from area of high molecular concentration to area of low concentraton; rate is very rapid and complete mixing with alveolar air is accomplished in less than a second |
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Term
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Definition
| volume of air inspired with each breath |
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Term
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Definition
| number of tidal volumes taken per minute |
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Term
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Definition
| product of the number of breaths per minute and the tidal volume |
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Term
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Definition
| volume in which gas exchange does not occur |
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Term
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Definition
| portion of tidal volume in which gas exchange occurs |
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Term
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Definition
| product of number of breaths per minute and tidal volume minus dead space |
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Term
| typical values of ventilatory volume |
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Definition
| tidal volume:500 ml; frequency-15/min; minute volume-7500 ml; dead space-150 ml; alveolar ventilation-5250 ml/min |
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Term
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Definition
| RV; volume of air remaining in the respiratory system at end of greatest possible expiration |
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Term
| functional residual capacity (FRC) |
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Definition
| volume of air in the respiratory system at the resting level |
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Term
| total lung capacity (TLC) |
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Definition
| volume of air in the respiratory system at the end of greatest possible inspiration |
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Term
| expiratory reserve volume |
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Definition
| FRC-RV; volume that can supplement tidal volume on expiration |
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Term
| inspiratory reserve volume |
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Definition
| voume that can supplement tidal volume on inspiration |
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Term
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Definition
| volume of air that can be inspired following expiration |
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Term
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Definition
| greatest possible of air that can be expelled following the greatest possible inspiration |
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Term
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Definition
| RV=1500; FRC=2625; TLC=6600ml; RV/TLC=22%; VC=5100mL |
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Term
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Definition
| all volume except RFC, TLC, and RV can be measured using this device |
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Term
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Definition
| used to measure FRC, TLC, and RV using He; known amount of He contained in volume V1; opening valve and mixing takes place and same amount now distributed in total volume (V1+V2); and V2=V1(C1/C2-1) |
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Term
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Definition
| used to measure FRC, TLC, and RV using He; known amount of He contained in volume V1; opening valve and mixing takes place and same amount now distributed in total volume (V1+V2); and V2=V1(C1/C2-1) |
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Term
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Definition
| determines FRC method needs very accurate measurements of N2 concentration |
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Term
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Definition
| measurement of FRC measure total volume of gas in lung including those trapped behind closed airways not just ventilated lung volume |
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Term
| restrictive ventilatory pattern |
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Definition
| inspiration is limited by reduced compliance of the lung and/or chest wall or weakness of inspiratory muscles; TLC, VC, FRC, RV are all reduced; and expiratory flow at equivalent lung volumes is greater than predicted values because of elastic recoil |
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Term
| obstructive ventilatory pattern |
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Definition
| total lung capacity is abnormally large but expiration ends prematurely; early airway closure is brought about by increased smooth muscle tone or loss of elastic recoil as in emphysema |
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Term
| determination of total ventilation |
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Definition
| using valving system to collect expired gas; knowing the volume of collected gas and number of breaths and number of breaths per minute; tidal volume Vt=V/n and V(dot)t=Vt*f |
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Term
| alveolar ventilation determination |
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Definition
| V(dot)a; where gas exhange takes place; by knowing Vd can use V(dot)a=(Vt-Vd) |
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Term
| other option for measuring alveolar ventilation |
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Definition
| V(dot)CO2=V(dot)a*FaCO2 where FaCO2 equals fraction of CO2 in alveolar gas; VdotCO2 measured by collecting expired gas in a bad over time and measuring its volume and CO2 concentration |
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Term
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Definition
| space of conductating airways |
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Term
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Definition
| in disease some alveoli may be ventilated but do not exchange gas |
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Term
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Definition
| anatomic plus alveolar dead space |
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Term
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Definition
| used to determine the dead space using principle that all CO2 in expired air originates in alveoli; dead space volume= (%CO2 alveolar-%CO2 expired)*(tidal volume)/(%CO2 alveolar) amounts to about 150-200ml |
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Term
| distribution of inspired air |
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Definition
| 1.two lungs-anatomical difference in size leads to unequal distribution of inspired air; 2. within a lung- 3 times as much inspired air goes to the dependent portion of the lung because alveoli at the base are smaller and more compliant |
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Term
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Definition
| directly proportional to the pressure difference between alveoli and the mouth (Pm-Palv) and inversely proportional to airway resistance (R) |
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Term
| ways to create the pressure gradient that causes gas to flow in and out of the alveoli |
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Definition
| 1. increase of decrease the pressure at the mouth relative to the alveolar pressure, as done by external positive pressure ventilators; 2. increase or decrease alveolar pressure relative to pressure at the mouth; occurs in spontaneous ventilation and when decreasing body surface pressure results in a decrease in alveolar pressure |
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Term
| effect as generation number increases |
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Definition
| 1. radii of the individual ariways decrease; 2. more airways are in parallel with each other; 3. lower the gas flow velocity |
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Term
| total resistance of a generation of airways |
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Definition
| depends on radius of the airways, length of the airways, viscosity of the gas (r^4); having many airways in parallel results in relatively low resistance |
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Term
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Definition
| Nr=pvd/mu (p=gas density; v=gas velocity; d=airway diameter; mu=gas viscosity) if Nr<1000 flow is laminar (small airways); if Nr>2000 the flow is turbulent (large airways); if Nr is between 1000 and 2000 then transitional flow occurs |
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Term
| turbulent flow in airways |
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Definition
| airflow in large airways is turbulent even during quiet breathing; this causes more energy to be required to achieve a given gas flow and the pressure gradient must be greater |
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Term
| pressure required to overcome energy lost to turbulence |
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Definition
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Term
| total pressure gradient required to establish a specific gas flow |
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Definition
| deltaP=Vdot*R+KVdot^2; 80% of resistance occurs in large airways at the 4th or 5th airway generation due to turbulent flow |
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Term
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Definition
| type of pulmonary resistance; produced by air moving through the airways (80% of total resistance) |
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Term
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Definition
| contributes to about 20% of the total resistance which is produced 1. tissue resistance caused by movement of lung and chest wall tissues and 2. inertial resistance (breathing frequency and density of gas) |
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Term
| influence of lung volume on dimensions of airways |
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Definition
| small brocnhi, bronchioles, and respiratory bronchioles have attachements to lung parenchyma so that with increases in lung volume, the airways are stretched also; 2. large airways are exposed to pleural pressure, at high lung volumes pressure on outer surface of airways becomes more negative and transmural pressure becomes larger and airways increase in size |
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Term
| neural control of airways |
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Definition
| airways contain smooth muscle is able to contract and relax to influence airway size; large airways have more dense innervation |
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Term
| stimulation of parasympathetic |
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Definition
| causes increased release of ACh due to action of ACh on muscarinic receptors, decreased airway radius, increased airway resistance, decreased anatomical dead space and eventually enlarges the alveoli |
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Term
| stimulation of sympathetic nerves |
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Definition
| cause release of norepinephrine, relaxation of airway smooth muscle via the action of neurotransmitter on smooth muscle, bronchiolar dilation, decreased airway resistance (occurs during aerobic exercise) |
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Term
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Definition
| Ptp=Palv-Ppl; equal to elastic recoil when there is no airflow; increases and decreases with lung volume |
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Term
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Definition
| Ptc=Ppl-Pbs; equal in magnitude to elastic recoil of the chest when theres no airflow, increases and decreases with chest volume |
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Term
| transmural respiratory system pressure |
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Definition
| Prs=Palv-Pbs; is zero at end of inspiration and expiration when no gas is flowing, equal to net passive elastic recoil pressure of the whole respiratory system when airflow is zero |
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Term
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Definition
| volume of structure when there is no net external force applied to it; structure will attempt to collapse if it is above its unstressed volume (as lungs are doing) |
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Term
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Definition
| during quiet breathing it is below unstressed volume and trying to expand; in times of increased inspiratory effort thorax can be above its stressed volume |
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Term
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Definition
| respiratory muscles relaxed, recoil of lungs and force produced by the thorax trying to expand are equal but opposite and Prs=0 and volume of gas is at FRC; pleural pressure is negative and there is thin layer of fluid and lungs cannot seperate from chest wall |
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Term
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Definition
| respiratory muscles relaxed, recoil of lungs and force produced by the thorax trying to expand are equal but opposite and Prs=0 and volume of gas is at FRC; pleural pressure is negative and there is thin layer of fluid and lungs cannot seperate from chest wall |
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Term
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Definition
| occurs when thorax is penetrated; air will enter thorax and lung will collapse to its unstressed volume and thoracic wall will expand to reach its unstressed volume |
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Term
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Definition
| normally active process that results from diaphragm contracting from phrenic nerve and thorax changes shape (both cephalo-caudal and anterior-posterior increase) and lungs pulled to a larger volume |
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Term
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Definition
| normally active process that results from diaphragm contracting from phrenic nerve and thorax changes shape (both cephalo-caudal and anterior-posterior increase) and lungs pulled to a larger volume |
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Term
| effect of volume change to gas flow |
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Definition
| increase lung volume decreases pleural pressure which decreases alveolar pressure and causes gas to flow from mouth and nose; volume that enters=tidal volume |
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Term
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Definition
| normally a passive process; gas flows from the alveoli through the airways out of the mouth and nose; occurs because relaxation of the diaphragm and external intercostals; energy to drive air out comes from that which was stored in the elastic structure of the lungs |
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Term
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Definition
| accessory muscles of expiration contract to assist in the more rapid movement of gas from alveoli; rectus abdominus contract to increase intraabdominal pressure and pushes diaphragm; other accessory muscles come into play like SCM and scalenes |
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Term
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Definition
| force that overcomes both lung compliance and resistance during dynamic breathing (=change in elastic pressure plus change in resistive pressure) or =deltaV/C+RVdot |
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Term
| instances where deltaPpl equal to elastic pressure |
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Definition
| 1. during static inflation gas flow is approximately zero; 2. during dynamic breathing at end of expiration, end of inspiration |
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Term
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Definition
| on the static compliance curve of the lung the largest increase in volume vs pressure occurs at the FRC; compliance of apical alveoli is less than basal alveoli apical alveoli are stretched by weight of the lung and are larger |
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Term
| determination of lung compliance |
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Definition
| 1. structure of the lung (elastin and collagen); 2. surface tension; harder to inflate than deflate because of surfactant |
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Term
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Definition
| during inspiration the surfactant molecule are rearranged; during expiration the more optimal arrangement of surfactant molecule lessens surface tension; if lungs filled with fluid the gas liquid interface is eliminated and no surface tension |
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Term
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Definition
| phospholipid produced by pulmonary type II alveolar cells; 1. reduces surface tension; 2. keeps alveolar pressure in small and large alveoli equal which prevents small alveoli from collapsing into larger ones |
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Term
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Definition
| P=2T/r (T=surface tension; r=radius) |
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Term
| premature infants and surfactant |
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Definition
| have a very low pulmonary compliance; high pressures are required to ventilate the lungs thus increasing energy consumption and may cause respiratory fatigue |
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Term
| function of central control systems in breathing |
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Definition
| attempt to minimze the work of breathing by altering the frequency and tidal volume while preserving alveolar ventilation; if resistance increases will decrease frequency of ventilation while increasing the tidal volume, while preserving alveolar ventilation |
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Term
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Definition
| are compressible and when pleural presssure is greater than pressure in the lumen the wall of the airway cannot support the compressive force and airway collapses |
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Term
| collapse during inspiration |
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Definition
| cannot collapse because at all levels the tranmural pressure is positive |
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Term
| collapse during passive expiration |
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Definition
| airways cannot collapse because transmural pressure is positive across the whole airway |
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Term
| collapse during forced expiration |
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Definition
| can collapse at some airway levels the transmural pressure becomes negative and compressive force is created |
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Term
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Definition
| point in the airway where transmural pressure becomes zero |
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Term
| determination of collapse |
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Definition
| depends on how negative the transmural pressure is and the thickness of the airway wall |
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Term
| increase in force of expiration |
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Definition
| equal pressure point is moved toward the alveoli and chance of airway collapse increases because of the thinner walls |
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Term
| increase in lung compliance |
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Definition
| lungs are less stiff and pressure due to elastic recoil is decreased and equal pressure point moves distally and increase change of collapse |
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Term
| effort independence of expiratory flow |
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Definition
| when patient inspires to TLC and then exhales the flow he or she can produce while exhaling first 20% is effort dependent once 20% has been exhaled the expiratory flow becomes effort independent and further effort will not increase flow |
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Term
| shape of flow-volume curve |
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Definition
| 1. lung compliance-inverse relationship between lung compliance and expiratory flow at any volume; 2. airway resistance-inverese relationship between airway resistance and expiratory flow at any volume |
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Term
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Definition
| due to work due to elastic forces (lung compliance) and resistive forces (lung resistance); decreasing lung compliance or increasing lung resistance will increase work of breathing |
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Term
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Definition
| results in high airway resistance caused by asthma, bronchitis, emphysema |
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Term
| ventilatory pattern of obstructive lung disease |
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Definition
| decreased FEV(1sec); total lung capacity typically abnormally large but expiration ends prematurely and early airway closure is brought about by increased smooth muscle tone of bronchi or loss of elastic recoil; RV,FRC, TLC abnormally high but VC reduced due to increase in RV |
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Term
| work of obstructive lung disease |
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Definition
| more pressure need to overcome airway resistance and deltaPr is greater than normal and if compliance is normal that delta Pe is normal; work of breathing is increased |
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Term
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Definition
| the ratio of FEV(1sec) divided by FVC and shows lung function; obstructive ratio ~40% and restrictive is ~90% |
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Term
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Definition
| decrease in lung compliance caused by pulmonary fibrosis or reduced compliance of lung or chest wall or weakness of the inspiratory muscles |
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Term
| ventilatory pattern of restrictive lung disease |
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Definition
| vital capacity is decreased; TLC, VC, FRC and RV are all reduced and expiratory flow at equivalent lung volumes is greater than predicted values because of increased elastic recoil; more pressure than normal required to maintain lung at any given volume (deltaPe greater at all points in cycle); work of breathing is increased |
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Term
| energy requirements for respiration |
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Definition
| 1. during quiet breathing oxygen cost of breathing is less than 5%; 2. during voluntary hyperventilation or exercise the oxygen cost increases to 30%; 3. O2 brething cost may increase to 25% in patients with lung disease limiting their exercise capacity |
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Term
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Definition
| each gas in a mixture exerts its own partial pressure in proportion to its concentration in the mixture; sum of partial pressure of component gases equals the total pressure |
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Term
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Definition
| at equilibrium pressure exerted by molecules of a gas dissolved in the liquid is equal to partial pressure of gas in the air; volume of gas dissolved depends upon its solubility |
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Term
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Definition
| =solubility*partial pressure |
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Term
| composition of inspired air in the tracheo-bronchial tree |
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Definition
| temp:37 degrees; 760mmHg; fully saturated with H2O vapor (47mmHg); 02 (21%-150mmHg); N2(79%-563mmHg); CO2 (O%-0mmHg) |
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Term
| variation in alveolar gas tensions in inspiration |
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Definition
| in beginning first air to enter is alveolar air which filled the conducting pathways at the end of the previous expiration and after this the fresh inspired air enters the alveoli |
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Term
| prevention of respiratory gas tensions |
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Definition
| relatively small volume of fresh air is added to, mixes with the relatively large volume of air already present in the alveoli |
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Term
| composition of alveolar air |
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Definition
| N2 (80%-573mmHg); O2 (14%-100mmHg); CO2 (5.6%-40mmHg); H2O vapor (47mmHg) |
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Term
| factors which determine the mean partial pressure of alveolar CO2 |
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Definition
| 1. rate at which CO2 is added to alveolar air (depends on production of CO2 by tissues-200ml/min); 2. rate at which CO2 removed from alveoli |
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Term
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Definition
| ventilation which decreases the PaCO2 to below the normal range (less than 40mmHg) |
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Term
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Definition
| ventilation which increases the PaCO2 to above normal range (greater than 40 mmHg) |
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Term
| factors which determine the mean partial pressure of alveolar O2 |
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Definition
| 1. rate at which O2 is added to alveolar air; hyperventialtion increases rate and increases PO2; hypoventilation decreases; 2. rate at which O2 is removed from the alveoli by the blood (determined by use of O2 use of tissues-normal 250ml/min) |
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Term
| respiratory gas exhange ratio |
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Definition
| ratio of volume of CO2 leaving the blood to the volume of O2 taken up by the blood (depends on tissue metabolism) |
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Term
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Definition
| respiratory gas exchange ratio when individual is in steady state and is basal |
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Term
| determination of mean alveolar gas tension for CO2 |
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Definition
| 1.direct analysis of expired alveolar air; 2. ideal alveolar CO2 tensions assume lung is homogeneous with respect to blood flow and ventilation and CO2 tension of arterial blood is same as ideal alveolar CO2 |
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Term
| mean alveolar O2 tension determination |
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Definition
| 1. ideal PAO2 calculate using alveolar gas equation (PAO2=PlO2-PACO2(FlO2+(1-FlO2)/R)) |
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Term
| modified alveolar gas equation |
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Definition
| PAO2=PlO2-PACO2 when 1. R=1 and/or 2. FlO2=1.0 (100% O2); or PAO2=PlO2-(PaCO2/0.8) when brething air and when R=8 |
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Term
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Definition
| provides nutrients to airways through terminal bronchioles; warms air; bronchopulmonary anastomosis-provides nutrient to alveolar cells if pulmonary circulation is impaired |
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Term
| smooth muscle of pulmonary circulation |
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Definition
| have short thin walled smooth muscles and decreases from arteries less than systemic circulation; high compliance, low absolute pressure, small pressure gradients, and low resistance |
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Term
| proximity to heart of pulmonary circulation |
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Definition
| close to heart so pulsatile flow despite high vascular compliance |
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Term
| vascularization of pulmonary circulation |
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Definition
| extremely vascularized and receives entire CO, large blood resevior (10% total blood volume) |
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Term
| vascularization of pulmonary circulation |
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Definition
| extremely vascularized and receives entire CO, large blood resevior (10% total blood volume) |
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Term
| non-gas exchange function of pulmonary circulation |
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Definition
| 1.acts as a filter; 2. endothelial cell enzymes modify circulating chemical substances; 3. endothelial cells release substances which modify vascular tone (NO) |
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Term
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Definition
| Qp=(Ppulmart-Pleft atrium)/PVR |
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Term
| active determinants of pulmonary blood flow that increase PVR |
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Definition
| 1. neural regulation-PNS not involved; SNS has small role acting on vein;2. chemical regulation-TXA2,catecholamines, histamine, angiotensin II, PGF2, serotonin, low pH; 3. low oxygen-inhibits vasorelaxtant mediators (cyclooxygenase, nitric oxide synthase), high blood viscosity |
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Term
| active determinants that decrease PVR |
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Definition
| no neural regulation and chemical regulation-circulation hormones, bradykinin, isoproteronol, PGE, endothelial cells |
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Term
| passive determinants effect of gravity |
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Definition
| arterial pressure is greater than venous pressure and both increase from top to bottom of the lung and alveolar pressure constant throughout; Zone 1-Palv>Part>Pven, normally small area of lung increasaed in tall people and with forced expiration; Zone 2-Part>Palv>Pvenous-flow determined by transmural pressure across alveolar capillary; Zone 3-Part>Pven>Palv |
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Term
| role of vascular recruitment and distension on PVR |
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Definition
| arteries are wide and compliant with little resistance to flow, not all are perfused at rest recruitment of these increases parallel pathways and distension of perfused vessels increases radius |
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Term
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Definition
| 1. increase in either pulmonary artery or venous pressure; 2. PVR decreases with a decrease across the circulation; 3. pulmonary artery pressure does not increase with increasing CO |
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Term
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Definition
| predominantly alveolar capillaries directly surrounding and connected to alveoli, transmural pressure across these is inversely related to lung volume, resistance increased at high lung volume and decreased at low lung volume |
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Term
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Definition
| pulmonary arteries and arterioles mostly connected to airways, transmural pressure across these vessels is directly related to lung volume; resistance is decrease at high lung volume and increased at low lung volume |
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Term
| lung volume on pressure and resistance |
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Definition
| at FRC alveolar and extra-alveolar resistance is at its lowest |
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Term
| major determinants of pulmonary hypertension |
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Definition
| 1. chronic hypoxia; 2. obstruction of blood flow in pulmonary circulation; 3. obstruction to outflow of blood flow from pulmonary circuit; 4. abnormally high blood flow over long period of time; 5. tissue and/or lung abnormalities |
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Term
| effects of chronic hypoxia |
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Definition
| 1. direct-oxygen mediated vasoconstriction and smooth muscle hyperplasia; 2. prolonged increase in pulmonary artery pressure mediates smooth muscle hypertrophy |
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Term
| fluid not accumulating in interstial tissue, alveoli or pleural spacee |
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Definition
| despite fact that pulmonary capillaries are leakier than systemic capillaries and capillaries filter fluid along the entire length and fluid is not reabsorbed |
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Term
| Starling forces favoring filtration |
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Definition
| favor filtration into interstitial space; capillary hydrostatic pressure is higher at the bottom of the lung than at the top; interstitial hydrostatic pressure is negative and is higher at the top of the lung; interstitial colloid osmotic pressure is higher than systemic |
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Term
| Starling forces opposing filtration |
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Definition
| capillary osmotic pressure; net outward driving force resulting in 20 ml/hr filtered and removed by the lymphatics |
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Term
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Definition
| great redundency and compliance draining off up to 10x normal volumes; travel within perivascular and peribronchial bundles and are absent near the alveoli |
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Term
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Definition
| fluid will accumulate first in interstitial space and ultimately in the alveoli when lympahtics are overwhelmed; caused by increased vascular permeability, increased interstitial protein concentration, increased capillary hydrostatic pressure |
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Term
| sequelae of pulmonary edema |
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Definition
| causes airway obstruction, increased surface tension, and a diffusional barrier; decreasing lung volume and compliance and PaO2 and increases resistance and work of breathing which increases PaCO2 |
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Term
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Definition
| thin layer of fluid exists between the visceral and parietal pleura; parietal pleura prefused by systemic capillaries |
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Term
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Definition
| accumulation of pleural fluid resulting from rate of pleural fuid formation exceeding the removal by blocked lymphatic drainage, cardiac failure, and infection |
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Term
| forms of transported oxygen in blood |
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Definition
| 1. physically dissolved in plasma; 2. reversibly bound to hemoglobin within RBC; O2 content in blood is sum of these |
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Term
| volume of O2 dissolved in the end pulmonary blood |
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Definition
| depends on 1. solubility of O2 in blood (0.03 mlO2/mmHg/L); 2. partial pressure of O2 in alveolar air- by increasing PAO2, amount of dissolved oxygen increases |
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Term
| transport of O2 as oxyhemoglobin |
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Definition
| major mode of transport in blood; RBC has larger SA, rapid diffusion, high concentration of hemoglobin |
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Term
| characteristics of hemoglobin |
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Definition
| 1. one molecule combines with each of four heme group; 2. at 100% on gm of Hb combines with 1.34 ml O2 |
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Term
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Definition
| number of mls of O2 combined with Hb in 100ml blood when Hb is 100% saturated |
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Term
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Definition
| the PO2 at which the Hb is 50% saturated; as O2 molecules bind successively to heme groups in the hemoglobin molecule allosteric changes take place producin an S-shaped curve |
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Term
| oxyhemoblobin dissociation curve |
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Definition
| 1. flat portion of the curve is the "loading" portion; 2. steep portion is the loasing portion; 3. P50 is indication of affinity of Hb for oxygen |
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Term
| factors that shift curve to the right |
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Definition
| P50 to increase and decrease Hb affinity; 1. increase in temperature; 2. increase blood PCO2; 3. increase in blood H+ concentration; 4. increase in chemical 2,3 DPG in red cell |
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Term
| factors which shift oxyhemoglobin curve to the left |
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Definition
| 1. decrease in temp; 2. decrease in PCO2; 3. increase in pH; 4. decrease in level 2,3 DPG; 5. CO poisoning |
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Term
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Definition
| less hemoglobin available for combination with O2; oxyhemoglobin dissociation curve is shifted to the left |
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Term
| factors which influence O2 delivery to cells |
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Definition
| 1. O2 content of the blood (Hb concentration and arterial O2 tension); 2. blood flow (volume of blood delivered to tissues/min); 3. A-V O2 difference (volume extracted by tissues) |
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Term
| responses to increased metabolic needs of the cells |
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Definition
| causes increase in CO2, decrease in pH, and increase in temp shift Hb curve to left more O2 release; O2 extraction also increased |
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Term
| responses to reduced PaO2 of arterial blood |
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Definition
| 1. ERF stimulates EPO which increases RBC and Hb; 2. increase in 2,3 DPG; 3. aortic chemoreceptor recognizes and increases blood flow; and increase in capillaries increases blood flow |
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Term
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Definition
| bluish, purple color of skin, nail beds and mucous membranes occurs when more than 5gHb/100ml of blood deoxyhemoglobin |
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Term
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Definition
| 1. dissolved gas in plasma and RBC; 2. bicarbonate in plasma and RBC; 3. as CO2-Hb combination in the RBC (carbaniohemoglobin |
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Term
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Definition
| 1. dissolved gas in plasma and RBC; 2. bicarbonate in plasma and RBC; 3. as CO2-Hb combination in the RBC (carbaniohemoglobin |
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Term
| CO2 dissolved in the blood |
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Definition
| CO2 diffuses rapidly through cell membranes and tissue fluid and proportional to PCO2 |
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Term
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Definition
| carries the bulk of CO2 from dissolved CO2 by hydration and HCO3- diffuses out of RBC in exchange for Cl-; H+ which is formed is buffered by hemoglobin and HHb is formed and pH is decresed |
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Term
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Definition
| small portion of dissolved CO2 in RBC combines with NH2 of hemoglobin |
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Term
| osmotic pressure changes during CO2 processing |
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Definition
| HCO3- ions inside the RBC are new osmotically active particle and H20 moves into the cell and it swells and HCO3- exchange across the RBC membrane |
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Term
| factors influencing the CO2 content of blood |
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Definition
| 1. partial pressure of CO2; 2. number of RBC; 3. amount of deoxyhemoglobin present |
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Term
| relation of blood O2 content to CO2 content |
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Definition
| at any given partial pressure the blood CO2 content is greater than O2 content despite the higher PO2 in arterial blood |
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Term
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Definition
| CO2 carrying power of blood is increased in presence of deoxyhemoglobin |
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Term
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Definition
| O2 dissociation from hemoglobin is increased as PCO2 increases and pH decreases |
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Term
| effect of CO2 on acid-base balance of the body |
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Definition
| 1.hydration of CO2 produces free H+; 2. increased CO2 content of body fluids due to hypoventilation produces a respiratory acidosis; 3. decreased CO2 content of body fluids produces a respiratory alkadosis (hyperventilation) |
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Term
| component parts of the diffusion pathway |
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Definition
| 1. a tissue barrier (aveolar epithelium and capillary endothelium); 2. blood (plasma and RBC membrane) |
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Term
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Definition
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Term
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Definition
| area available for gas exchange depends on 1. SA of alveoli; 2. number of open alveolar capillaries |
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Term
| diffusivity coefficient(D) in Ficks equation |
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Definition
| depends on molecular weight of the gas and the solubility of the gas in the tissue (proportional to S/(MW)^(1/2) |
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Term
| driving force in Ficks equation |
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Definition
| is the partial pressure gradient of the respiratory gases between alveolar gas and pulmonary capillary blood |
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Term
| chemical reaction involved in gas transfer rate through blood components |
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Definition
| 1. N2O does not combine with Hb so partial pressure of N2O rises very rapidly; 2. affinity of CO for Hb is so great that the partial pressure in blood reises very little as blood moves through alveolar capillary; 3. O2 binds according to Hb according to oxyhemoglobin dissociation curve and partial pressure rises fairly rapidly |
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Term
| factors involved in the gas transfer rater through blood components |
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Definition
| 1. chemical reactions within RBC; 2. blood flow |
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Term
| perfusion-influenced transfer |
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Definition
| aka perfusion limited transfer; gas tensions in the alveoli and pulmonary capillary blood reach equilibrium and amount of gas transfer depends on amount of blood flow |
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Term
| diffusion-influenced transfer |
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Definition
| aka diffusion-limited transfer; gas tensions in the alveoli and the pulmonary capillary blood fail to reach equilibrium; amount of gas depends on the diffusion properties of gas exchange surfaces |
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Term
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Definition
| normally limited by blood flow (perfusion-limited) but in some disease cases it is limited by diffusion (diffusion-limited) |
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Term
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Definition
| normally limited by blood flow (perfusion-limited) but in some disease cases it is limited by diffusion (diffusion-limited) |
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Term
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Definition
| normally limited by blood flow (perfusion-limited) but in some disease cases it is limited by diffusion (diffusion-limited) |
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Term
| normal gas transfers for O2 |
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Definition
| partial pressures of O2 in alveolar gas and O2 dissolved in pulmonary capillary blood normally come into equilibrium in about .25 sec; when PAO2 is abnormally low the partial pressure gradient is small and the time for equilibrium is increased |
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Term
| normal movement of CO2 from the pulmonary capillary blood into the alveoli |
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Definition
| small partial pressure gradient; CO2 diffuses and equilibrates rapidly because of its high solubility |
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Term
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Definition
| measurement of A and L are not possible in the lung so A, D, L are all combined into one term in Ficks equation; this is the volume of gas which diffuses from alveoli into the blood in one minute per unit of partial pressure gradient between alveolar gas and the pulmonary capillary blood |
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Term
| factors determining diffusin capacity |
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Definition
| 1. available diffusing surface; 2. thickness of diffusing membrane; 3. diffusivity coefficient of the gas; 4. reaction rate of the gas with hemoglobin |
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Term
| role of CO in measuring diffusing capacity of the lung |
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Definition
| 1. at low concentrations uptake by RBC is rapid and Hb not saturated; 2. at a given PACO the amount of CO that moves into blood from the alveoli is solely dependent upon thickness of the alveolar membrane and area available for diffusion; Normal DLCO=17ml/min/mmHg |
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Term
| changes in diffusing capacity |
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Definition
| 1. increases whenever the number of pulmonary capillaries that are open increases; 2. decreases whenever alveolar surfaces or pulmonary capillaries are destroyed by disease; 3. may decrease when the alveolar walls are thickened due to disease |
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Term
| effects of hyerventilation on gas exchange |
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Definition
| 1. PACO2 is decreased and PAO2 is increased; 2. end pulmonary capillary blood show corresponding changes in the partial pressure; 3. due to flatness of oxyhemoglobin curve at PO2 greater than 100mmHg will not significantly increase the O2 content of the blood; 4. because of linearity of CO2 curve decreasing PCO2 will significantly decrease CO2 content of the blood |
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Term
| effects of hypoventilation of gas exchange |
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Definition
| 1. PACO2 is increased and PAO2 is decreased; 2. end pulmonary capillary blood show changes in partial pressures of the gas; 3. due to steepness of oxyhemoglobin curve PO2s less than 90mmHg decreasing PO2 will significantly decrease the O2 content of blood; 4. increasing PCO2 will significantly increase the CO2 content of the blood |
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Term
| effects of impaired diffusion on gas exchange |
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Definition
| alveolar gas concentrations and partial pressures are normal but alveolar capillary blood fails to reach equilibrium with the alveolar gas; reduced oxygen tension in end pulmonary capillary blood (diffusion can be increased by increasing the O2 concentration of the inspired gas |
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Term
| effect of pulmonary capillary blood flow and alveolar ventilation on gas exchange |
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Definition
| these factors vary independently within lung units; and V/Q ratio can vary from one to infinity in individual lung units; and combined effect of individual variations determine mean alveolar, en pulmonary capillary and arterial gas tensions |
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Term
| effect of V/Q ratio of zero |
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Definition
| 1. the alveolar gas is not renewed and gas tensions come into equilibrium with entering venous blood; 2. end pulmonary blood has same gas tensions as the venous blood; 3. absolute intrapulmonary shunt |
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Term
| absolute intrapulmonary shunt |
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Definition
| wasted blood flow when a V/Q ratio is zero |
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Term
| effect of V/Q ratio of infinity |
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Definition
| 1. no gas exchange takes places because no blood flows (creating alveolar dead space); 2. alveolar gas tensions are the same as the inspired air |
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Term
| absolute alveolar dead space |
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Definition
| when the V/Q ratio is infinity and no blood flow to the alveoli |
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Term
| effect of low V/Q ratios (<.8) |
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Definition
| 1. alveolar PCO2 is greater than normal and PO2 less than normal; 2. end pulmonary capillary CO2 content is greater than normal and O2 content is less than normal; 3. contribute to physiologic intrapulmonary shunts |
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Term
| how does low V/Q ratios occur |
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Definition
| bronchi are blocked with secretions, bronchi are narrowed or when alveolar compliance is decreased; also occurs when blood flow is increased relative to ventilation |
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Term
| effect of high V/Q ratios (>.8) |
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Definition
| 1. partial pressure of O2 is greater than normal; 2. PCO2 is reduced below normal; 3. end pulmonary capillary O2 content is not increased but the CO2 content is decreased; 4. contribute to alveolar dead space |
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Term
| ventilation/perfusion matching at mid-lung |
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Definition
| 1. V and Q match relatively well and ratio is about 0.8; 2. end-ulmonary capillary gas tensions are within normal range |
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Term
| ventialtion/perfusion matching at lung apex |
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Definition
| 1. alveoli are large and compliance is relatively low and ventilation is slightly reduced; 2. blood flow is reduced more than ventilation is reduced; 3. V/Q ratio is high; 4. blood leaving has higher PO2 and lower PCO2 |
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Term
| ventilation/perfusion matching at lung base |
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Definition
| 1. alveoli are small and compliance high and ventilation is 3 times than at apex; 2. blood flow is increased about 10 times due to gravity; 3. V/Q ratio is low; 4. has slightly lower O2 tension and slightly higher CO2; 5. produces very small physiologic intrapulmonary shunt |
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Term
| mean end pulmonary gas content |
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Definition
| determined by percentage of total blood flow and end pulmonary gas content leaving each area; equal to sum of (%QT)(CcGas); NOT determined by the average of the contents from all areas |
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Term
| compensation of V/Q ratios |
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Definition
| 1. regions of high V/Q ratios do not compensate for the decrease in the O2 content caused by the regions of low V/Q; 2. regions of high V/Q ratios compensate for the increase in the CO2 content caused by regions of low V/Q |
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Term
| mixing of blood in left heart |
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Definition
| 1. end pulmonary capillary blood from alveoli with normal gas exchange and normal V/Q; 2. end pulmonary blood from aveoli with abnormal V/Q ratios (high and low); 3. blood from anatomical shunts |
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Term
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Definition
| blood from alveoli with low V/Q ratios and from anatomical shunts |
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Term
| sources of venous admixture |
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Definition
| 1. physiological intrapulmonary shunts due to low V/Q ratio (present in normal lungs in dependent portion of lung); 2. alveoli with imparied diffusion; 3. anatomical shunts (broncial veins and thebesian veins) or cardiac spetal defects or AV fistula within pulmonary circulation |
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Term
| effect of venous admixture |
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Definition
| produces A-a gradient; O2 tensions are lower and CO2 are high in venous admixture and dilutes normal end pulmonary capillary blood and significant changes in arterial PO2 occur |
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Term
| changes in arterial PO2 due to venous admixture |
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Definition
| 1.due to blood flow from low V/Q areas the PO2 of pulmonary venous blood is slightly less than the PO2 of mixed alveolar gas; 2. oxygen tension of the blood in venous admixture from shunts is less than the mean partial pressure of O2 in mixed alveolar gas; 3. size of A-a gradient for O2 depends upon the volume and origin of the venous admixture (forms about 2% of CO amounting to 4-10 mmHg) |
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Term
| venous admixture in disease |
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Definition
| volume of the venous admixture may be as high as 40-50% of CO and A-a gradient may be up to 70 mmHg |
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Term
| changes in arterial PCO2 due to venous admixture |
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Definition
| 1. CO2 tension of blood leaving the alveoli is in equilbrium with alveolar CO2 tension; 2. CO2 tension in venous admixture is higher than the mean alveolar PCO2; 3. arterial CO2 not increased significantly b/c gradient between shunted blood and arterialized blood no more than 4-6 mmHg-volume shunted is small, CO2 dissociation curve is steep and linear and alveolar with high V/Q ratios do compensate somewhat |
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Term
| A-a gradient occurs for CO2 |
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Definition
| arterial PCO2 does increase by small amount but when this occurs the PaCO2 is returned to normal by respiratory control mechanisms but A-a gradient not eliminated; 1. increased ventilation lowers the PCO2 and CO2 content in all alveoli and end pulmonary capillary blood; 2. does not appreciably increase the O2 content in end-pulmonary capillary blood with high V/Q ratios |
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Term
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Definition
| ratio Qs/Qt=(CcO2-CaO2)/(CcO2-CvO2); shunt equation used when mixed venous blood is added to end pulmonary capillary blood; intrapulmonary shunt can also be assessed by calculating what the shunt would be if all the shunted blood passed through completely unventilated alveoli |
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Term
| use of arterial CO2 tensions |
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Definition
| 1. assess adequacy of alveolar ventilation; 2. combination with HCO3- to assess acid-base status of the body; 3. combination with PlO2 to calculate mean alveolar PAO2 using alveolar gas equation |
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Term
| arterial O2 tensions utilized |
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Definition
| 1. assess O2 supply to peripheral tissues by calculating the O2 content of the blood; 2. combination with calculated PAO2 to asses the A-a gradient, the size of the shunt and the extent of V/Q mismatch |
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Term
| functions of respiratory control system |
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Definition
| 1. maintenance of automatic, regular, rhythmical breathing; 2. adjustment of tidal volume and breathing rate in order to provide sufficient alveolar ventilation for gas exchange (O2 supply and CO2 elimination) and create a pattern of breathing with the lowest energy requirement; 3. adjustment of the breathing pattern during speech, swallowing, and postural changes |
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Term
| major aspects of CNS control of respiration |
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Definition
| 1. behavioral and voluntary control and automatic control influence final common pathway alpha motorneuron and innervate respiratory muscles and cause ventilation; 2. sensors provide feedback to change CNS control over breathing |
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Term
| origination of basic respiratory rhythm |
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Definition
| automatic control originates in the brainstem |
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Term
| origination of voluntary and behavioral control |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| increased breathing and include hyperventilation |
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Term
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Definition
| increased breathing resulting in a decrease in PaCO2 |
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Term
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Definition
| increased rate of breathing; rapid shallow breathing |
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Term
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Definition
| difficult breathing "air hunger" |
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Term
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Definition
| cessation of breathing at full inpiration |
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Term
| medullary respiratory centers |
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Definition
| source of the spontaneous basic respiratory rhythm; activity no adequate to sustain life for any prolonged period of time; have capacity to generate spontaneous rhythmic discharge |
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Term
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Definition
| consists mainly of inspiratory neurons and drives the ventral group and contralateral diaphragm |
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Term
| ventral respiratory group |
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Definition
| consists of both inspiratory and expiratory neurons and drives the contralateral intercostal neurons and diaphragm |
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Term
| respiratory centers in pons |
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Definition
| strengthen and regularize the activity of the medullary respiratory centers |
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Term
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Definition
| in lower pons; 1. tonically active and enhances inspiration; when isolated from upper pons, the higher centers, and vagal input it produces apneustic breathing |
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Term
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Definition
| in upper pons (nucleus parabrachialis) and exerts a controlling effect on the apneustic center and strengthens and regularizes rhythmical respiratory activity |
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Term
| vagus nerve input during lung inflation |
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Definition
| vagus nerve has inhibitory effect on inspiration due to pulmonary stretch receptors |
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Term
| factors modifying the basic, rhythmical acitivty of pontine-medullary centers |
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Definition
| 1. state of wakefulness; 2. temperature; 3. hypothalamus and higher centers; 4. eating, drinking, speech; 5. afferent information from sensory receptors |
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Term
| origination of afferent information to brainstem |
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Definition
| 1. chemoreceptors; 2. sensory receptors within the lungs and tracheobronchial tree (stretch receptors and irritant receptors); 3. pain receptors and other peripheral sensory receptors; 4. mechanoreceptors in the respiratory muscles and chest wall |
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Term
| control centers for voluntary and behavioral control of respiration |
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Definition
| 1. acts associated with consciousness can alter patterns by acting on medullary-pontine centers; 2. other neural patterns can bypass medullary-pontine centers and terminate directly on alpha motorneurons; 3. voluntary breathing may remain intact even when the medullary centers are destroyed |
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Term
| causes of hypoventilation in CNS |
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Definition
| 1. overdose-barbiturates; 2. tumors; 3. post surgery-increased cranial pressure; 4. cerebral thrombus or emboli; 5. Ondine's Curse-no autonomic control |
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Term
| sites for control of PaCO2 |
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Definition
| central medullary chemoreceptors and the peripheral chemoreceptors |
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|
Term
| location of central chemoreceptors |
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Definition
| at or just below the surface of the ventro-lateral region of the medulla-distinct from the medullary respiratory centers |
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Term
| response of central chemoreceptors |
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Definition
| 1. sensitive to the level of H+ in the ECF around the cells; 2. increase in the ECF H+ stimulates receptors that stimulate the medullary respiratory centers to produce increase in alveolar ventilation; 3. not stimulated by hypoxemia; 4. very low PaCO2 can cause apnea |
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Term
| factors that influence level of H+ in ECF of central chemoreceptors |
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Definition
| 1. composition of cerebral capillary blood; 2. composition of CSF; 3. metabolism of surrounding tissue |
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Term
| stimulus-response relationship of central chemoreceptors |
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Definition
| 1. alveolar ventilation increases linearly with increasing PaCO2; 2. response of central chemoreceptors is depressed during sleep, anaethesia, barbiturates, hypoxia, and increased pH; 3. central chemoreceptors are extremely sensitive, producing significant changes in ventilation in response to small changes in PCO2; 4. most important chemical ventilatory control site under normal conditions |
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Term
| peripheral arterial chemoreceptors |
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Definition
| 1. aortic and carotid bodies respond to increases in PaCO2 and decreases in pHa by increasing their neural activity; 2. responses important if PaCO2 is changed rapidly and during conditions of hypoxia; 3. carotid bodies have high blood flow allowing for rapid sampling of blood gas levels vs longer term of central chemoreceptors |
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|
Term
| role of carotid bodies in PaO2 |
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Definition
| solely responsible for ventilatory adjustments to changes in PaO2 |
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|
Term
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Definition
| low arterial oxygen tension, high arterial PCO2, low pH, lowering O2 supply by severe vasoconstriction, severe hypotension, drugs like cyanide, nicotine |
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|
Term
| reflex responses to stimulation of peripheral chemoreceptors |
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Definition
| 1. afferent activity from carotid body carried via IX; 2. afferent activity from aortic bodies carried via X; 3. reflex integrated in the respiratory center in the medulla and increase in ventilation; 4. ventilatory chemoreflex response is primarily due to afferent information from carotid bodies |
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Term
| carotid chemoreceptor activity |
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Definition
| increases in carotid receptor activity and ventilation as PaCO2 increases and synergistically with decreasing PaO2 |
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|
Term
| effects of aterial PCO2 on chemoreceptors |
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Definition
| abnormally high arterial CO2 levels stimulate both central and peripheral chemoreceptors to increase ventilation |
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|
Term
|
Definition
| at normal levels peripheral chemoreceptors have a low grade tonic activit; when arterial PO2 is reduced below about 60mmHg peripheral chemorecptors are stimulated, central chemoreceptors are depressed and ventilation is increased due to input from peripheral chemoreceptors |
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|
Term
| significance of chemoreceptors in presence of abnormal respiratory gases |
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Definition
| both respond to rise in arterial CO2; when PO2 is reduced-central mechanisms are depressed and carotid bodies major drive to ventilation and peripheral chemoreceptors produce tachycardia and improves O2 delivery to the tissues |
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|
Term
| effect of chemoreceptors in metabolic acidosis |
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Definition
| 1. low pHa stimulates carotid bodies; 2. ventilation increases |
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|
Term
| effect of carotid bodies in sleep apnea |
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Definition
| carotid body stimulation produces increased respiratory effort and arousal |
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|
Term
| receptors in respiratory system which can alter ventilation |
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Definition
| 1. pulmonary stretch receptors; 2. irritant receptors; 3. J receptors (juxta-capillary receptors); 4. joint, golgi tendon organs, and muscle spindles |
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