Just to recap…

I’m not sure how much of this I’ve ever put on here, and how much is just floating around my head. Here’s a recap of some of the main concepts:

– Blood vessel tone, and indeed blood pressure is not uniform and systemic. Rather, it’s adjusted locally in order to turn on or off functions and processes within the brain and body by allowing or restricting blood flow.

– Blood flow is controlled by the neurotransmitter serotonin. That’s pretty much its sole role.

– Genetic or environmental factors may cause a disruption in normal blood flow regulation, or of the ability of the blood vessels to effectively dilate and contract. Endothelial health may be poor, and the elasticity or ability to react of the blood vessels reduced.

– Alterations in perception can be the result of abnormal blood flow within the brain. For example, states which involve depressive or hallucinatory symptoms may be the result of insufficient blood flow, whilst mania, delusion and insomnia may be the result of increased blood flow. The symptoms exhibited will vary according to the specific area of the brain affected by the alteration of normal blood supply.

– Instability of blood vessel tone leads to varying  levels of mental discomfort ranging from anxiety to psychosis depending on the level of instability. Agents which stabilise the blood vessel tone (for example nicotine, anti psychotics, amphetamine) bring relief, which may help us to understand the mechanism behind some addictions, or at least the mechanism behind cravings and withdrawal.

– Consciousness is dependant upon sufficient blood flow to (unknown) structures within the brain, and the level of consciousness can vary according to blood flow.

– Sleep is merely a mechanism to enable the cardiovascular system to rest, recover and repair. Some of the available serotonin is converted in the pineal to melatonin, leaving less to “keep open the gates” of consciousness. Breathing slows and the body cools. Blood vessels constrict, and the heart slows, needing less effort to maintain circulation at the minimum level required, reducing strain. The reduction in blood flow combined with the vasoconstriction disrupt blood flow to the structures within the brain sufficiently to cause loss of consciousness. Disruption of blood flow to other centres in the brain give rise to the hallucinations which we refer to as dreams (an experiment involving administering psilocybin to volunteers undergoing a brain scan last year found that the substance was reducing blood flow in areas of the brain whilst hallucinations were being experienced)

I’ll come back to this, need to write about something else I was just thinking about…

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~ by funnyinthehead on May 13, 2013.

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