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Fight or flight response

Discussion in 'Scenarios' started by Ediron, Dec 4, 2009.

  1. Ediron

    Ediron New Member

    "Flight or Fight" (sympathetic nervous system stimulation), environmental influence, low blood sugar

    Can someone explain this to me in greater detail, as well as parasympathetic nervous system
  2. here is a nice little video, explains the bare basics.

    what exactly do you need explained? Any of us could explain the whole shebang: stimuli, catecholamines, synapses, neurotransmitters, but you could just as easily Google that:)

    try googling autonomic nervous system.

    JPINFV Gadfly

    404: No Meme Found
    Sympathetic Nervous System:

    The sympathetic nervous system is the system which causes the "fight or flight" response. The responses include a dilation of the pupils (hence more light is let through), bronchial dilation (easier air flow into the lungs), an increase in the strength and rate of cardiac contraction along with an increase in the conduction velocity in the heart (more cardiac output), constricts arteries (except for some coronary arteries), increases blood sugar and inhibits digestion and bladder contraction among other things. The sympathetic nervous system also causes ejaculation.

    The preganglionic sympathetic nerve axons exit the spinal cord only in the thoracic and lumbar regions and enter the sympathetic chain ganglia where they either synapse onto the postganglionic nerve cells or move up or down the chain ganglia until they reach the appropriate level. At the ganglion, the sympathetic nervous system uses acetylcholine to transmit the signal across the synaptic cleft to the post ganglionic cells. From here, the post ganglionic axon runs and synapses on the target organ where it uses norepinephrine (except at the adrenal medullas where epinephrine is released into the blood stream). Thus, the sympathetic nervous system is characterized by short preganglionic axons and long postganglionic axons.

    The postganglionic receptors utilize numerous different subtypes depending on where it is and what it hopes to achieve. The highlights include:

    Alpha 1 receptors: vasoconstriction
    Alpha 2 receptors: release of glucagon and the inhibition insulin production.
    Beta 1 receptors: Increase in cardiac output
    Beta 2 receptors: relaxation of smooth muscles cells (e.g. bronchial tube relaxation, hence the use of beta 2 agonists for reactive airway issues)
    Beta 3 receptors: Increase of lypolysis.
  4. Linuss

    Linuss Active Member

    The preganglionic neurotransmitter for all ganglions is acetocholyne, whereas the postganglionic neurotransmitter can either be acetocholyne or norepinepherine. ACh is used for the parasympathetic system while most of the sympathetic system uses nor-epi as it's postganglionic neurotransmitter, with the exception of sweat glands that use ACh.
  5. The sympathetic, parasympathetic, and sympatho-adrenal divisions of the autonomic nervous system are all activated in response to falling blood sugar. Hypoglycemia provokes a sequence of counterregulatory metabolic, neural, and clinical responses.Low levels of glucose in the blood plasma stimulates the adrenal glands to release catecholamines. High levels of catecholamines stimulate the sympathetic nervous system, causing sweating, shaking, heart palpitations and hunger. Insulin secretion decreases whereas glucagon, epinephrine, norepinephrine, pancreatic polypeptide, cortisol, and growth hormone increase.This leads to a cycle of hypoglycemia unawareness that induces a further decrease in counterregulatory hormone responses to hypoglycemia.
  6. Smash

    Smash Member

    [Spelling pedant] Acetylcholine (ACh) not acetocholyne. [/Spelling pedant]

  7. mycrofft

    mycrofft Still crazy but elsewhere

    Central California
    A homier way to get one's head around it...the Disney version.

    You/your brain are riding around in the skull protected from the rest of the guts and stuff by the neck and the blood-brain barrier. You are a thoroughbred, you only (mostly) run on dextrose and oxygen, and then you need your wastes removed. Add some downtime for sleep and things are peachy.

    If something threatens the brain, it's finer reasoning starts breaking down rapidly (hence the succes of late night QVC and used car lots open on New Year's Day). It has hardwired programs to get it away from wherever it is, on the Darwinianly selected program that wherever you are is worse than anyplace else, and whatever is nearby may be the cause of the affront; this is why drunks and severe hypoglycemics will "come up swinging" and stumble around trying to restlessly "go somewhere". The early part of the hypoglycemic reaction is to get food. Lastly, if you're hurt or being pursued and you go down, you will go down swinging, biting, defecting and all that will make you less appealing, and if it doesn't save you, it may make that sabertoothed tiger thnink twice the next time it smells "Man".

    These are signs and symptoms, the anatomy is the wiring to perform this and the pharmacy is how we can help reestablish the brain's cozy little nest of sugar, oxygen, and waste removal. (Oh, yeah, pressure regulation too, it resents being crammed down the foramen magnum by swelling).
  8. Linuss

    Linuss Active Member


    Look at the time I typed it! :p

    That's my excuse and I'm sticking to it!
  9. Ediron

    Ediron New Member

    Thank you, Everyone (=

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