Across
- 1. the medulla oblongata is __________ to the pons.
- 6. peripheral chemoreceptors are located in ___________ ____________ (origin of internal carotids) and aortic bodies (in aortic arch).
- 7. ___________ receptors in the smooth muscle of the airways also provide input to the DRG – hering-breuer reflex (inhibit inspiration to prevent overinflation of lungs)
- 8. 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.
- 12. the hering breuer reflex involves stretch receptors in the lungs signalling/inhibiting the DRG to reduce inspiration (prevent over ____________ of lungs)
- 17. arterial PCO2 stimulates ________ __________________ (in ventral medulla oblongata) – most important. Stimulates indirectly due to increased H+ concentration in brain ECF. Also stimulates peripheral chemoreceptors (weak).
- 19. 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.
- 20. 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.
- 21. 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.
- 22. the respiratory centre is made up of ________ aggregations of neural cell bodies.
- 24. higher voluntary control of breathing is _________ by chemotactic centres with arterial PCO2 gets too high.
- 27. the ______________ centre is rostral to the apneustic centre within the pons.
- 30. the pre-botzinger activity has ________________ activity (rate mediated by input from other parts of brain) that rhythmically stimulates the DRG. Resulting in inspiration.
- 31. very ____ levels of CO2 in blood (>75mmHg) will depress neural function, depress ventilation, bad, death.
- 33. mechanoreceptors in the airways initiate the ___________ and sneezing reflexes.
- 34. in __________, ventilation is synchronised with gait at canter and gallop (not walk and trot)
- 35. a ________ in arterial PCO2 can cause a drop in brain ECF [H+], this will reduce stimulation of ventilation.
Down
- 2. 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.
- 3. the respiratory system has an important role in _____ -_____ balance.
- 4. _____________________ in the airways provides input to the DRG. They initiate the coughing/sneezing reflex.
- 5. peripheral chemoreceptor signals from the carotid bodies travel along cranial nerve _____ to the DRG.
- 6. there are peripheral _________________ (carotid and aortic) and central ________________ (ventral part of medulla oblongata) that signal the DRG.
- 9. the ___________ and pneumotaxic centres provide input to the DRG. They fine tune the output from medullary centres to make inspiration and expiration smooth.
- 10. peripheral chemoreceptor signals from the aortic bodies travel along cranial nerve _____ to the DRG.
- 11. the respiratory centre is located within the _____________.
- 13. arterial PO2 is monitored ONLY by ____________ chemoreceptors. Only sensitive to dramatic change in PO@ (eg <60mmHg – point where Hb 90% saturated)
- 14. the ____ ___________ complex is located within the medulla oblongata just below the DRG, and cranial to the VRG (see diagram)
- 15. __________ chemoreceptors are located in the ventral part of the medulla oblongata (below the DRG/VRG/prebotzinger etc)
- 16. 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).
- 17. arterial P __________ __________ levels are the most important input in regulation of ventilation under normal conditions.
- 18. 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
- 23. the ____ (abb) is located in the medulla oblongata, along with the VRG and pre-botzinger complex
- 24. the pneumotaxic centre switches ____ inspiration while the apneustic centre prevents it being switched ____.
- 25. the VRG stimulates ___________ and accessory inspiratory muscles during exercise.
- 26. the DRG firing stimulates inspiratory nerves innervating the _____________. Results in normal regular inspiration.
- 28. low PO2 depresses all ________ function except chemoreceptors. Dramatic drop in arterial PO2 will be sensed by peripheral chemoreceptors, stimulate increased ventilation. Life saving mechinaism.
- 29. the _________ respiratory group responds to pacemaker activity from the pre-botzinger complex. The DRG firing stimulates inspiratory nerves innervating the diaphragm.
- 30. the _____ is the site of the pneumotaxic and apneustic centres (two of the five groups making up the respiratory centre).
- 32. 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.