Some of the ancient Greeks thought that sweat was basically CSF, part of the circulation of the lymphatic system, and I strongly suspect they were correct.
Cerebrospinal fluid is a liquid produced mainly in the choroid plexus and it is distributed through the ventricular system, basal cisterns, and subarachnoid space. CSF surrounds the brain, giving it support and it has been described to protect the brain from shocks and also participates in homeostasis and metabolism. According to Wang et al, 2014 the CSF in the subarachnoid space is the CNS thermal buffer (based in reports by Hayward and Baker, 1968b). Zenker and Kubik, 1996 describe in detail the process of brain temperature homeostasis in humans both externally (via venuous blood from the skin of the head and nasal membranes) and internally (dura mater transmitting temperature changes to CSF)
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