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Nervous system

  1. Feb 20, 2005 #1
    Easiest/best ways to describe the differences between:

    Somatic and autonomic nervous system
    -somatic has the motor neurone's cell body inside the CNS, while autonomic has its motor neurone's cell body outside the CNS, in the ganglia (2 neurones carry impulse from CNS to organ)

    Sympathetic and parasympathetic NS.
    -Sympathetic is concerned with 'flight or fight'; parasympathetic is 'rest and digest'.
    -In sympathetic NS, ganglia are connected to each other? (not sure about that)
    -Parasympathetic NS - synapse between preganglionic neurone and autonomic neurone is inside the organ (while sympathetic is in the ganglia close to spinal cord).
    -Parasympathetic involves the vagus nerve.
    -and what about the neurotransmitters? Both use acetylcholine, but sympathetic uses noradrenaline too?

    posterior and anterior pituitary glands- posterior: secretes hormones made by hypothalamus, into blood (eg ADH and oxytocin)
    - anterior: neurones in hypothalamus produce, and secrete hormones into blood vessels. Hormones then travel via blood to anterior pituitary gland, and affect secretions of other hormone.

    I'm unsure about differences between posterior and anterior.

    please, if you can correct or add to the above, PLEASE REPLY!

    Thankyou :)
  2. jcsd
  3. Feb 22, 2005 #2


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    I'll start here, for no other reason than because it's the easiest for me to answer without thinking much (I've been busy with other stuff so haven't replying to questions that require me to think too hard about something other than the work I'm trying to distract myself from while online :rolleyes:) Anyway, you're going to get the very boiled down version here.

    The hypothalamus produces a bunch of hormones (in various cells and in various places in the hypothalamus). Some of these hormones are called releasing hormones. These releasing hormones are secreted into a collection of blood vessels (pituitary portal vessels) that run from the hypothalamus (a very small part of it known as the median eminence) to the anterior pituitary (also called the adenohypophysis). When they reach the anterior pituitary, they stimulate the production and/or release of other hormones within cells of the pituitary. These hormones then are released into the general blood circulation to reach more distant targets in the body to either act upon those organs or stimulate or inhibit release of other hormones from those more distant glands.

    Another set of hormones produced in the hypothalamus are released by neurons that project all the way down to the posterior pituitary (also called the neurohypophysis). They are then stored there until released into the general circulation to act on more distant targets.

    So, the anterior pituitary produces a new set of hormones in response to those that reach it from the hypothalamus while the posterior pituitary acts more like a warehouse to temporarily store hormones produced by the hypothalamus to be later distributed to the rest of the body.
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