as a consequence of reduced blood volume the macula densa
Macula densa Macula densa cells sense changes in sodium chloride level, and will trigger an autoregulatory response to increase or decrease reabsorption of ions and water to the blood (as needed) in order to alter blood volume and return blood pressure to normal.
Cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found in the brain and spinal cord. It is produced in the choroid plexuses of the ventricles of the brain, and absorbed in the arachnoid granulations. There is about 125mL of CSF at any one time, and about 500mL is generated every day. CSF acts as a cushion or buffer for the brain, providing basic mechanical and immunological protection to the brain inside the skull. The CSF also serves a vital function in cerebral autoregulation of cerebral blood flow.