Resp - Lecture 10: Control of ventilation

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Across
  1. 3. mechanoreceptors in the airways initiate the ___________ and sneezing reflexes.
  2. 5. in __________, ventilation is synchronised with gait at canter and gallop (not walk and trot)
  3. 6. the _____ is the site of the pneumotaxic and apneustic centres (two of the five groups making up the respiratory centre).
  4. 8. higher voluntary control of breathing is _________ by chemotactic centres with arterial PCO2 gets too high.
  5. 9. the DRG firing stimulates inspiratory nerves innervating the _____________. Results in normal regular inspiration.
  6. 12. conscious control of ventilation by _______ cortical centres occurs with the following activities: breath holding, voluntary coughing, swallowing, vocalisation, defecation, parturition, changes in gait in some species. This ______ control is overridden by chemotactic centres with extreme changes in arterial PCO2 (cant voluntarily hold breath forever).
  7. 13. the respiratory centre is located within the _____________.
  8. 15. peripheral chemoreceptors sensing PO2 only respond to arterial PO2 (dissolved in plasma), not the O2 content of the blood. Therefore, in ____________ patients with low Hb, there may be low O2 in blood (less Hb to bind to), but a normal PO2 of 100mmHg (dissolved). This would mean that hypoxic drive would not be stimulated.
  9. 16. arterial PCO2 stimulates ________ __________________ (in ventral medulla oblongata) – most important. Stimulates indirectly due to increased H+ concentration in brain ECF. Also stimulates peripheral chemoreceptors (weak).
  10. 23. the ______________ centre is rostral to the apneustic centre within the pons.
  11. 25. the pneumotaxic centre switches ____ inspiration while the apneustic centre prevents it being switched ____.
  12. 26. the _________ respiratory group responds to pacemaker activity from the pre-botzinger complex. The DRG firing stimulates inspiratory nerves innervating the diaphragm.
  13. 28. the pneumotaxic centre acts to terminate inspiration. The apneustic centre prevents switching off of inspiration, in this way, the groups in the pons __________ balance one another.
  14. 29. a ________ in arterial PCO2 can cause a drop in brain ECF [H+], this will reduce stimulation of ventilation.
  15. 31. low PO2 depresses all ________ function except chemoreceptors. Dramatic drop in arterial PO2 will be sensed by peripheral chemoreceptors, stimulate increased ventilation. Life saving mechinaism.
  16. 32. the VRG stimulates ___________ and accessory inspiratory muscles during exercise.
  17. 36. peripheral chemoreceptor signals from the carotid bodies travel along cranial nerve _____ to the DRG.
  18. 37. __________ chemoreceptors are located in the ventral part of the medulla oblongata (below the DRG/VRG/prebotzinger etc)
Down
  1. 1. the medulla oblongata is __________ to the pons.
  2. 2. the hering breuer reflex involves stretch receptors in the lungs signalling/inhibiting the DRG to reduce inspiration (prevent over ____________ of lungs)
  3. 4. arterial PO2 is monitored ONLY by ____________ chemoreceptors. Only sensitive to dramatic change in PO@ (eg <60mmHg – point where Hb 90% saturated)
  4. 7. three of the five groups making up the respiratory centre, the DRG, VRG and pre-botzinger complex, are within the __________ __________, while the other two (apneustic centre and pneumotaxic centre) are within the pons
  5. 9. the ____ (abb) is located in the medulla oblongata, along with the VRG and pre-botzinger complex
  6. 10. very ____ levels of CO2 in blood (>75mmHg) will depress neural function, depress ventilation, bad, death.
  7. 11. there are peripheral _________________ (carotid and aortic) and central ________________ (ventral part of medulla oblongata) that signal the DRG.
  8. 14. the ___________ and pneumotaxic centres provide input to the DRG. They fine tune the output from medullary centres to make inspiration and expiration smooth.
  9. 16. arterial P __________ __________ levels are the most important input in regulation of ventilation under normal conditions.
  10. 17. increased H+ in ARTERIES (aka _________) will NOT stimulate the central chemoreceptors, but does stimulate peripheral chemoreceptors. ________ will cause an increase in ventilation. Opposite for alkalosis.
  11. 18. peripheral chemoreceptors are located in ___________ ____________ (origin of internal carotids) and aortic bodies (in aortic arch).
  12. 19. _____________________ in the airways provides input to the DRG. They initiate the coughing/sneezing reflex.
  13. 20. the ____ ___________ complex is located within the medulla oblongata just below the DRG, and cranial to the VRG (see diagram)
  14. 21. carbon dioxide diffuses much more readily across the BBB than __________ ions do. Therefore PCO2 can cause elevated H+ in brain ECF – stimulates central chemoreceptors – medullary respiratory centre –stimulates ventilation.
  15. 22. the respiratory system has an important role in _____ -_____ balance.
  16. 24. the ______ (abb) is activated by the DRG when the demand for ventilation increases (eg during exercise). The ____ stimulates spinal neurons that innervate expiratory muscles, and accessory inspiratory muscles.
  17. 27. ___________ receptors in the smooth muscle of the airways also provide input to the DRG – hering-breuer reflex (inhibit inspiration to prevent overinflation of lungs)
  18. 30. H+ concentration within the ____________ will NOT stimulate the central chemoreceptors. It cannot readily cross the BBB. Instead, CO2 does, and makes H+ inside the BBB. Does influence peripheral chemoreceptors however.
  19. 33. the pre-botzinger activity has ________________ activity (rate mediated by input from other parts of brain) that rhythmically stimulates the DRG. Resulting in inspiration.
  20. 34. peripheral chemoreceptor signals from the aortic bodies travel along cranial nerve _____ to the DRG.
  21. 35. the respiratory centre is made up of ________ aggregations of neural cell bodies.