AN SC 310 - 21

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  1. What are respiratory muscles controlled by?
    Motor neurons
  2. What part respiration is th phrenic nerve a part of and what does it control?
    • Inspiration
    • Diaphragm
  3. What part of respiration is the external intercostal nerve a part of and what does it control?
    • Inspiration
    • External intercostal muscles
  4. What part of respiration is the internal intercostal nerve a part of and what does it control?
    • Expiration
    • Internal intercostal muscles
  5. What are the 2 types of breathing?
    • Quiet - contraction of inspiratory muscles = burst of APSs, no contraction of expiratory muscles
    • Active - contraction of inspiratory muscles = large burst of APs, contraction of expiratory muscles = burst of APs
  6. What components generate the breathing rhythm?
    • Inspiratory/Expiratory Neurons
    • Respiratory Control Centres of Medulla
    • Respiratory Control Centres of Pons
    • Central Pattern Generator
  7. What does the central pattern generator establish?
    Respiratory Cycle
  8. What are the 3 levels of control in respiration?
    • 1. Respiratory rhythmicity centers - medulla oblongata (DRG & VRG), control basic breathing
    • 2. Apneustil and Pneumotaxic Centers - pons, adjust output of respiration (rate and depth)
    • 3. Higher Centers - hypothalamus, limbic system, cerebral cortex, important but not crucial for survival
  9. What receptors are a part of peripheral input to respiratory centers?
    • Chemoreceptors
    • Pulmonary stretch receptors
    • Irritant receptors
    • Muscle and join proprioceptors
  10. What do chemoreceptors do?
    Detect blood levels of O2 and CO2
  11. What are the 2 types of chemoreceptors?
    • Peripheral in carotid bodies
    • Central in medulla oblongata
  12. What do peripheral chemoreceptors mainly respond to?
    Changes on blood pH
  13. What levels of PCO2 in blood result in coma and death?
    • Coma >90 mm Hg
    • Death >180 mm Hg
  14. What do central chemoreceptors respond to?
    • Changes in pH of CSF
    • Not directly responsive to CO2, repsonds via pH (^CO2 = \/pH)
    • Not responsive to [O2]
  15. What are the steps of the response to hypoventilation?
    • Decreased O2 b/c less breathing
    • Increased [H+] from increase CO2
    • Chemoreceptors fire
    • Ventilation increased
    • Negative feedback to PCO2, [H+], PO2
  16. What are the steps of the response to hyperventilation?
    • Increased PO2
    • Decreased [H+] from decreased PCO2
    • Chemoreceptors fire
    • Ventilation decreased
    • Negative feedback to PCO2, [H+], PO2
  17. What is ventilation?
    Rate of air flow
  18. What is perfusion?
    Rate of blood flow
  19. What is the ventilation-perfusion ratio?
    • 1:1
    • VA/Q
  20. If there is an obstruction of an airway, what occurs?
    • VA/Q decreases
    • No exchange so \/ O2 ^ CO2 in blood, blood flow functioning normally
  21. If there is an obstruction of blood flow, what occurs?
    • VA/Q increases
    • Same exchange but in less blood due to lower blood flowing past alveoli so ^O2 \/CO2 in blood, alveoli are functioning normally
    • Vasodilation/constriction of vessels/alveoli to compensate
  22. How does an increase in PO2 affect bronchioles and pulmonary arterioles?
    • Bronchoconstriction
    • Vasodilation
  23. How does an increase in PCO2 affect bronchioles and pulmonary arterioles?
    • Bronchodilation
    • Vasoconstriction (increase amount of blood that come in contact with alveoli)
  24. What is normal blood pH?
  25. What body systems regulate blood pH?
    • Respiratory
    • Renal
  26. What is acidosis and what can it cause?
    • Blood pH < 7.35
    • CNS depression
  27. What is alkalosis and what can it cause?
    • Blood pH > 7.45
    • CNS over-excitation
  28. What are 2 things that can act as buffers in blood?
    • Hemoglobin (Hb + H+ <--> HbH)
    • Bicarbonate ions (HCO3- + H+ <--> H2CO3 <--> CO2 + H2O)
  29. What is the Henderson-Hasselbalch Eqn?
    pH = 6.1 + log [HCO3-]/[CO2]
  30. To maintain normal arterial pH at 7.4, what must the ratio of HCO3- and CO2 be?
  31. What system regulates [CO2]?
    Respiratory System
  32. What system regulates [HCO3-]?
    Renal (Kidneys)
  33. What is respiratory acidosis caused by?
    Increased [CO2]
  34. What is respiratory alkalosis caused by?
    decreased [CO2]
Card Set:
AN SC 310 - 21
2012-12-10 04:58:35
AN SC 310

Lecture 21 - The Respiratory System: Regulation of Ventilation
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