Some science behind the scenes
Cerebrospinal fluid (CSF)
Cerebrospinal fluid (CSF) is a clear colourless bodily fluid.
It is produced in the choroid plexus of the brain. It is drained away by the blood vessels and possibly by the lymph system. CSF connections with the lymphatic system are a bit more tenuous. There is some discussion at the moment as to whether there may be some relationship between CSF disorders, including hydrocephalus and impaired CSF lymphatic transport.
CSF is found within the dura mater, which is a sac that surrounds the spine and the brain – see spinal cord. The CSF occupies
- the space between the arachnoid mater and the pia mater in the spinal cord;
- the central canal of the spinal cord
- the ventricular system around and inside the brain and spinal cord
- various brain cavities - it seeps into the ventricles, cisterns, and sulci of the brain.
Thus our central nervous system and our brains are bathed in this fluid. The existence of CSF is used by all anaesthetists. When they want to knock you out they compare the density of the drug they are going to use with the density of your cerebrospinal fluid. This then tells them how a particular drug will spread ‘in the intrathecal space’ – the same space used by the CSF.
So any drug, endogenous chemical or other stuff that finds its way into the CSF will also find its way to the brain and all the organs of the brain – from the pineal gland to the pituitary gland, from the hydrocephalus to the amygdalas.
Emanuel Swedenborg, in a manuscript written between 1741 and 1744 unpublished in his lifetime, referred to it as "spirituous lymph".
Not without reason.
CSF ‘moves in a pulsatile manner throughout the CSF system with nearly zero net flow’. So it pulses. A very nice illustration of this pulsing CSF can be found via this link.
It is produced at a rate of 500 ml/day and turns over about 3.7 times a day. So a lot of pulsing.
CSF pressure varies depending on whether the person is standing up or lying down. It can increase when coughing. When lying down, the cerebrospinal fluid in the lumbar region is similar to the intracranial pressure.
It has four main purposes
- Buoyancy: The actual mass of the human brain is about 1400 grams; however, the net weight of the brain suspended in CSF is 25 grams. CSF enables the brain to maintain its ‘constituency’ - it is not crushed by its own weight.
- Protection: CSF protects the brain tissue from injury when jolted or hit.
- Regulating intercranial pressure - the amount of CSF in the brain can be increased or decreased affecting the blood supply - increasing it or decreasing it. When CSF pressure is elevated, cerebral blood flow may be constricted. As Wikipedia says “When disorders of CSF flow occur, they may therefore affect not only CSF movement but also craniospinal compliance and the intracranial blood flow, with subsequent neuronal and glial vulnerabilities”. So it affects the functions of the brain. The venous system is also important in this equation.
- Chemical stability: CSF flows throughout the inner ventricular system in the brain and is absorbed back into the bloodstream, via the blood brain barrier where the metabolic waste from the central nervous system is ‘rinsed’ away. This ‘waste’ can be all sorts of things from neurotransmitters to hormones, toxins and minerals, viruses and bacteria even funguses. The blood thus acts like a sort of waste pipe to take away unwanted waste.
Large amounts of CSF are drained into the blood through arachnoid granulations in the superior sagittal sinus – a vein - blue cold yin energy.
This corresponds to the crown chakra.
Here we have a picture of the Superior sagittal sinus and its veins showing the route of return of CSF fluid. As you can see it mirrors the Governor vessel used in acupuncture [Du] and a number of key trigger points.
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