Question

cerebrospinal fluid is returned to the venous blood via:
the blood brain barrier
dural sinuses
gap junctions
arachnoid villi
14 multiple choice 1 point
the ______ system governs the arousal of the brain.
parasympathetic
sympathetic
reticular activating
autonomic
15 multiple choice 1 point
these cells secrete mucous, so aromas can be detected by the olfactory receptors cells:
dendritic cells
glial cells
basal stem cells
supporting cells

Explanation:

Question 1 (Cerebrospinal fluid return):

Cerebrospinal fluid (CSF) is reabsorbed into venous blood through arachnoid villi (which protrude into dural sinuses). The blood - brain barrier regulates substance passage to the brain, gap junctions are for cell - cell communication, and dural sinuses are the site where arachnoid villi drain CSF, not the direct structure for return. So the correct option is arachnoid villi.

The reticular activating system (RAS) is responsible for regulating brain arousal, wakefulness, and attention. The parasympathetic system is for "rest - and - digest" functions, the sympathetic system for "fight - or - flight", and the autonomic system is a broader system including both parasympathetic and sympathetic, not specific to brain arousal. So the correct option is reticular activating.

Supporting cells in the olfactory epithelium secrete mucus, which helps dissolve odorants so that olfactory receptor cells can detect them. Dendritic cells are immune cells, glial cells support neurons in the CNS, and basal stem cells are for cell renewal in the olfactory epithelium, not for mucous secretion related to odor detection. So the correct option is supporting cells.

Answer:

arachnoid villi (the option with "arachnoid villi")

Question 2 (Brain arousal system):