Question

65. Where is bloodstream PCO2 monitored?

(a) lungs (b) aortic and carotid bodies (c) hypothalamus

66. Is PCO2 measured within the CNS?

(a) no (b) yes, within the brainstem (c) yes, within the hypothalamus

67. Is PO2 measured within the CNS?

(a) no (b) yes, within the brainstem (c) yes, throughout the brain

68. Glomus organs are innervated by sensory neurons. Are these sensory neurons stimulated byneurotransmitters released from Type I glomus cells?

yes or no

69. Does the structure of glomus organs enable direct sampling of arterial blood?

yes or no

70. Glomus organs are innervated by myelinated axons. Such axons are found within cranial nerve pairs IX andX (glossopharyngeal and vagus). Which type of glial cell myelinates axons within these nerve pairs?

(a) oligodendrocyte (b) fibrous astrocyte (c) Schwann cell

71. The sensory neuron axons that innervate glomus organs enter the CNS via the left and right solitary tracts. Where are the bodies of these sensory neurons?

(a) within the glomus organ (b) a ganglion at the base of each nerve (c) within the brainstem’s solitary nuclei

72. The term hypercapnia denotes elevated bloodstream PCO2. This condition induces acidemia, i.e. an arterialpH < 7.4. By convention, the underlying physiological reason (or process) is called acidosis. Consequently,acidemia can arise from either metabolic or respiratory acidosis. Ketogenesis and hypoventilation affordexamples of such processes. If arterial pH reaches 7.0, then CNS depression and coma follow. Acidemia iscountered by an autonomic reflex. Where does central integration occur for this reflex?

(a) sensory cortex (b) brainstem (c)hypothalamus