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Fig. 1 | Fluids and Barriers of the CNS

Fig. 1

From: The human central nervous system discharges carbon dioxide and lactic acid into the cerebrospinal fluid

Fig. 1

Comparisons of solute levels and pH between venous blood and CSF. The distribution of pO2 was higher in CSF than in venous blood, as were those of pCO2 and lactic acid, indicating that the brain and spine discharge CO2 and lactic acid into the CSF. The CSF was significantly more acidic than the venous blood. Levels of HCO3− and Na+ ions did not differ significantly between the venous blood and CSF. The grey-filled areas show the generally accepted normal ranges in arterial blood. All p-values are the result of a paired t-test. CSF, cerebrospinal fluid; HCO3, bicarbonate ion; pCO2, carbon dioxide partial pressure; pO2, oxygen partial pressure

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