Resp1- Resp Phys 2

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  1. Volume of air entering and leaving lungs during inspiration and subsequent expiration at rest.
    resting tidal volume (VT)
  2. Part of the tidal volume fills the _________ of the ___________ and the other part enters the ___________ to participate in ___________.
    dead space (VD); conducting zone; respiratory zone (VA); gas exchange
  3. Maximal volume of air above the tidal volume that can be inspired on the deepest inspiration (such as during exercise).
    inspiratory reserve volume (IRV)
  4. When we breathe in, VL ________, and when we breathe out, VL _________; tidal volume (VT) is...
    increases; decreases; the difference b/w the max and min VL.
  5. Volume of air remaining in lungs after expiration of resting VT.
    functional residual capacity (FRC)
  6. Functional residual capacity (FRC) is determined by...
    the balance b/w elastic recoil forces of the chest wall and lung (chest wants to expand, lungs want to contract/get smaller).
  7. Maximal volume of air (after VT) that can be expired on forced expiration (such as during exercise).
    expiratory reserve volume (ERV)
  8. Volume of air remaining in lungs after forced expiration and expulsion of expiratory reserve volume.
    residual volume (RV)
  9. How do you calculate reserve volume?
    RV= FRC - ERV

    • FRC= functional residual capacity
    • ERV= expiratory reserve volume
  10. Residual volume (RV) is determined by...(4)
    strength of respiratory muscles, lung compliance, stiffness of chest wall, airway patency
  11. With weakness, there is ________ expiratory reserve; therefore, FRC is ________.
    less; higher
  12. Maximal volume that can be expired after maximal inspiration.
    vital capacity (VC)
  13. How can you calculate vital capacity (VC)?
    VC= VT + IRV + ERV

    • IRV= inspiratory reserve volume
    • ERV= expiratory reserve volume
  14. Total air volume of both lungs at the end of maximal inspiration.
    total lung capacity (TLC)
  15. How can you calculate total lung capacity (TLC)?
    TLC = IRV + VT + ERV + RV

    • IRV= inspiratory reserve volume
    • ERV= expiratory reserve volume
    • RV= residual volume
  16. Volume of air in conducting airways.
    anatomic dead space (VD)
  17. Volume of alveoli that should be participating in gas exchange but are not.
    alveolar dead space
  18. What should alveolar dead space be in a normal, healthy animal?
    almost zero- alveolar dead space in abnormal and can indicate a blocked bronchiole, fluid in alveoli, etc.
  19. Alveolar dead space is minimized in normal animals by...
    ventialtion- perfusion matching (rate of VA ÷ rate of Q)
  20. Define physiologic dead space.
    anatomic + alveolar dead space; therefore, should equal anatomic dead space in a normal animal
  21. How is physiologic dead space quantified?
    volume of lung that is not producing CO2.
  22. The amount of air moving in and out of lung.
  23. Ventilation depends on... (2)
    respiratory rate (f- breaths/min) and tidal volume (VT- mL/breath).
  24. Volume of air entering or leaving lungs per minute.
    minute ventilation (V.M)
  25. How do you calculate minute ventilation (V.M)?
    f x VT

    with VT= VA + VD (must take dead space into account); therefore...

    • (f x V.A) + (f x V.D)
    • V.A + V.D
  26. Volume of fresh air entering alveoli per minute.
    alveolar ventilation rate (V.A)
  27. Explain how alveolar ventilation rate (V.A) is quantified.
    inspired air contains essentially no CO2; all CO2 in expired air must come from pulmonary capillary blood in functional alveoli; thus, V.A can be calculated from expired CO2.
  28. Why is alveolar ventilation rate more physiologically relevant than minute ventilation?
    with rapid shallow breathing (increased minute ventilation), all air is going into dead space them immediately being exhaled (low alveolar ventilation); with slow deep breathing (decreased minute ventilation), air makes it down to respiratory zone to have a physiologic effect (increased alveolar ventilation)
  29. Why should you avoid using an ET tube that is too long for the patient?
    you're filling dead space (the tube) when mechanically ventilating; therefore, alveolar ventilation requires MUCH higher volumes of air
  30. Increased ______________ is far more effective than increased _________ at increasing alveolar ventilation.
    depth of respiration; respiration rate (f)
  31. Decreased depth of respiration can lead to a critical reduction in alveolar ventilation rate because...
    dead space volume is fixed and must be ventilated on every breath; if VT decreases, dead space is still ventilated but alveoli get decreased air.
  32. With hypoventilation, there is a(n) ___________ ratio of CO2 production to alveolar ventilation rate.
  33. With hyperventilation, there is a(n) __________ ratio of CO2 production to alveolar ventilation rate.
  34. The diaphragm and intercostal muscles are _________ muscles; therefore, there is no _____________.
    skeletal; spontaneous contraction
  35. Breathing depends on cyclical ______________ by ____________.
    excitation of diaphragm and intercostal mm.; motor nerves
  36. Inspiration is triggered by...
    Expiration occurs when...
    • bursts of action potential to diaphragm and inspiratory intercostal muscles.
    • action potentials cease.
  37. At rest, active contraction of internal intercostals is ___________; expiration at rest is ___________.
    not necessary; a passive process
  38. Medullary inspiratory neurons ____________ with inspiration and ___________ with expiration.
    discharge in synchrony;cease firing
  39. What inputs from the pons modulate medullary inspiratory center firing? (4)
    apneustic center (terminate inspiration), pneumotaxic center (modifies apneustic), central chemoreceptors, baroreceptors
  40. What peripheral sensory nerve inputs help to modulate the activity of the inspiratory center of the medulla? (3)
    peripheral chemoreceptors, thoracic stretch receptors, J receptors
  41. Sensor systems provide feedback to the medulla regarding... (3)
    composition of arterial blood (peripheral chemoreceptors) and CSF (central chemoreceptors), spatial orientation of chest and lungs, ventilatory effort
  42. What is the most powerful ventilatory stimulus?
    high arterial partial presure of CO2 (Pa CO2)
  43. Where are peripheral and central chemoreceptors located?
    • peripheral- arterial walls
    • central- ventral surface of the 4th ventricle
  44. Central chemoreceptors are stimulated by...
    increase in brain extracellular fluid, mainly due to an increase in arterial partial pressure of CO2 (Pa CO2).
  45. Stimulation of central chemoreceptors results in...
    increased tidal volume (VT).
  46. Do changes in arterial partial pressure of oxygen affect central chemoreceptors?
  47. What are the 2 groups of peripheral chemoreceptors? Where are each located, and by what nerve do they signal?
    carotid bodies (at bifurcation of common carotid arteries- glossopharyngeal n.), aortic bodies (in aortic arch- vagus n.)
  48. Peripheral chemoreceptors are stimulated by... (2)
    decrease in arterial partial pressure of oxygen (contrast to central), increase in arterial [H+] due to increased arterial partial pressure of CO2 (ie. decreased arterial pH)
  49. Stimulation of peripheral chemoreceptors results in... (2)
    increase respiration rate (f), increased tidal volume (VT)
  50. Peripheral chemoreceptors are NOT stimulated by a decrease in O2 content of blood when _____________, such as in the case of... (2)
    Pa O2 remains normal; anemia (reduced Hgb so less total O2 carried by blood but the same amount of O2 dissolved in plasma), CO poisoning (competes with O2 for binding to Hgb but does not affect conc of O2 dissolved in plasma)
  51. Inhaling air containing elevated [CO2] results in __________; thus, _________ increases.
    PA CO2; Pa CO2
  52. Why are peripheral chemoreceptors so sensitive to arterial [CO2]?
    body pH must be kept in a very tight range to maintain integrity of enzymes/proteins/etc; therefore, slight increases in CO2, causing arterial pH to drop, elicits an increase in alveolar ventilation rate.
  53. Pa CO2 is stabilized at _________ (value) by the respiratory compensatory mechanism of chemoreceptors.
    40 mmHg
  54. What are the consequences of increase Pa CO2?
    increased [H+] (formation of carbonic acid, which dissociates to H+ and bicarb)--> increased arterial acid sensed by peripheral chemoreceptors--> stimulation of medullary inspiratory neurons
  55. Very high levels of arterial CO2 cause...
    direct suppression of activity of medullary inspiratory neurons.
  56. Arterial [H+] can be altered by... (2)
    excessive production of organic acids (metabolic acidosis) or excessive loss of [H+] (metabolic alkalosis) [both are independent of arterial CO2...respiratory system tries to compensate]
  57. Changes in arterial [H+] are mainly sensed by ___________; changes in ___________ help restore [H+] to normal at the expense of abnormal _________.
    peripheral chemoreceptors;  alveolar ventilation rate; Pa CO2
  58. Addition of lactic acid to blood in severe exercise, stimulating peripheral chemoreceptors.
    metabolic acidosis
  59. Metabolic acidosis triggers ____________ in order to... (2)
    hyperventilation; reduce Pa CO2 and lower arterial [H+] towards normal.
  60. Loss of H+ ions due to gastric vomiting, depressing peripheral chemoreceptors.
    metabolic alkalosis
  61. Metabolic alkalosis triggers __________ in order to... (2)
    hypoventilation; elevate Pa CO2 and help restore arterial [H+] towards normal.
  62. Factors that stimulation ventilation in exercise. (6)
    reflex inputs from mechanoreceptors in joints/muscles, increased body temperature, inputs to respiratory neurons form cortical centers, increased plasma [epinephrine], increased plasma [K+], conditioned response (mental preparation for an athletic event)
  63. Where are proprioceptors located?
    skeletal muscles of thoracic wall and diaphragm (more in intercostal mm.)
  64. Where are pulmonary stretch receptors located?
    airway smooth muscles, afferent to medulla
  65. Pulmonary stretch receptors are stimulated by ____________, triggering...
    large lung inflation volumes (very large tidal volume over an extended period of time); vagal inhibition of medullary inspiratory neurons.
  66. Pulmonary stretch receptors stimulate... (3)
    inhibit inspiratory neurons, promote tachycardia and bronchodilation
  67. What is the Hering-Breuer reflex?
    direct inhibition of inspiratory center due to a large, prolonged inflation volume--> prevents activation of inspiratory center by apneustic center.
  68. What are the 3 protective reflexes that are triggered by receptors b/w airway epithelial cells? What does each trigger?
    • cough reflex- triggers deep inspiration followed by violent expiration
    • sneeze reflex- triggers forcible contraction of diaphragm and chest wall
    • apneustic reflex- immediate cessation of respiration following inhalation of noxious gas
  69. Where are receptors that trigger the cough reflex?
    larynx, trachea, bronchi
  70. Where are receptors that trigger the sneeze reflex?
    nose and pharynx
  71. Nasal receptors that induce a sneeze are stimulated by... (4)
    cold air, odors, physical and chemical irritants
  72. Nasal receptors that induce a sneeze also induce... (3)
    increased mucus secretion, apnea (brief period when you don't breath right after a sneeze), reduced cardiac output.
  73. Laryngeal receptors that cause a cough are located in the _________ and respond to ___________.
    vocal cords; mechanical stimulation
  74. What is the reason an animal coughs when you properly intubate it?
    laryngeal receptors are stimulated by the ET tube, causing a cough reflex
  75. Juxtacapillary receptors (J receptors) are located in the __________ and are stimulated by ___________.
    alveolar walls; increased interstitial pressure (maybe due to microemboli, pulmonary edema)
  76. Activation of J receptors triggers... (5)
    tachypnea (primarily ventilating dead space), dyspnea, dry cough, uncomfortable sensation of pressure in chest, hypotension
  77. Mental anguish associated with inability to ventilate adequately, resulting from hypercapnia, increased workload of respiratory muscles, mental state.
  78. Voluntary control of breathing is accomplished by...
    descending pathways from cerebral cortex to motor neurons of respiratory muscles.
  79. What limits breath holding ability?
    voluntary control of breathing is possible, but it cannot override the physiologic stimulus of elevated Pa CO2 or [H+]
  80. Deliberate hyperventilation reduces ________ and elevates _________, which ultimately...
    Pa CO2; Pa O2; low Pa CO2 reduces respiratory drive.
  81. What is the valsalva maneuver?
    expiration against closed glottis to raise intrathoracic pressure, which is transmitted to the abdomen to help with defecation and parturition.
  82. What causes inspiratory stridor?
    inadequate dilation of upper airway on inspiration
  83. Failure of diaphragm and intercostal muscles impair gas exchange by reducing __________, even if the lung itself is normal.
    alveolar ventilation rate
  84. Contraction of the diaphragm without contraction of external intercostal muscles, causing the chest to narrow during inspiration.
    paradoxical breathing
  85. Describe Cheyne-Stokes breathing ventilatory pattern.
    regularly increasing then decreasing tidal volume follow by periods of apnea
  86. What can cause Cheyne-Stokes breathing ventilatory pattern? (2)
    [low bloodflow states] heart failure, hemorrhagic shock
  87. Describe Biot's breathing ventilatory pattern.
    grossly irregular breathing pattern
  88. What causes Biot's breathing ventilatory pattern?
    medullary lesions
  89. Describe Kussmaul breathing ventilatory pattern.
    rapid deep breaths
  90. What causes Kussmaul breathing ventilatory pattern?
    metabolic acidosis (ketoacidosis)- compensation by converting H+ to CO2, which is exhaled
  91. What is the primary muscle of respiration in mammals?
  92. What muscles maintain the patency of the upper airways?
    laryngeal and genioglossal muscles
  93. The effort required to breath is equal to...
    the work done by the respiratory muscles
  94. What are the determinants of the work of breathing? (2)
    elastic properties of the lungs/chest wall (compliance), flow resistive properties of airways/parenchyma (resistance)
  95. Degree of lung expansion at any time is proportional to ________, but how much it expands the lungs depends on __________.
    transpulmonary pressure (PTP); lung compliance (CL)
  96. The magnitude of change in lung volume produced by a given change in transpulmonary pressure.
  97. Lung compliance is measured by plotting _______ against _______.
    VL; PTP
  98. Compliance value measured when there is zero airflow (so no resistance).
    static compliance (CSTAT)
  99. Compliance value measured during active ventilation, usually at peak inspiratory pressure.
    dynamic compliance (CDYN)
  100. CDYN is always _________ than CSTAT.
    less than or equal to
Card Set:
Resp1- Resp Phys 2
2016-01-15 02:55:20
vetmed resp1

vetmed resp1
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