United States or Cyprus ? Vote for the TOP Country of the Week !
The work lacks also, in this first edition, a statement and discussion of the important all-or-none principle which is now applicable to voluntary muscle, probably, and to the neurones.
"I didn't have the heart to tell you after the last operation. The subvirus is attacking the internuncial neurones." I knew what that meant but was past caring. "We're not immortal not yet," I said. "I'm ready for the end." "We can still try," he said. I struggled to laugh but even gave up that little gesture. "Another operation? No, it can't make any difference." "It might. We don't know."
Although to the naked eye the nervous system is apparently made up of a number of different kinds of material, still we see, when we turn our microscopes upon it, that its parts are structurally the same. Reduced to lowest terms, the nervous system is found to be composed of minute units of structure called nerve-cells or neurones.
We are first apprised of their importance when we study the nervous system, and find that every incoming sensory message pushes on and on until it finds a motor pathway over which it may travel and produce movement. This is inevitable. The very structure and arrangement of the neurones is such that we are obliged to make some movement in response to objects affecting our sense organs.
Beginning with those at the outermost parts of the body, we find them located in the sense-organs, not only within the traditional five, but also within the muscles, tendons, joints, and internal organs of the body such as the heart, and digestive organs. In all these places we find ends of neurones which converge at the spinal cord and travel to the brain.
There are, indeed, a great number of original native tendencies, instinctive modes of action, based on the original connections of neurones in the central nervous system.
The beautiful woman sees no need for intelligence nor for understanding because she has always been able to outstrip her less attractive competitors in making the best match and securing the rich husbands. And so her neurones rarely "connect," or react, except to stimuli pertaining to things that will enhance her charms and increase her selling price.
Perhaps he would be fortunate. Maybe the reports would be late. Maybe his secretary's two neurones would fail to synapse this morning, and she'd lose them altogether. And, as long as he was dreaming, maybe Bailey would break his neck on the way to work.
A nervous system, with neurones placed end to end in such wise that, at the extremity of each, manifold ways open in which manifold questions present themselves, is a veritable reservoir of indetermination. That the main energy of the vital impulse has been spent in creating apparatus of this kind is, we believe, what a glance over the organized world as a whole easily shows.
The neural action accompanying this occurrence consists of an impression upon the nerve-cells in the eye, the conduction of the nervous current back to the visual area of the brain, the transmission of the current over association neurones to the motor area, then its transmission over the motor neurones, down the spinal cord, to the muscles that enable you to dodge the missile.
Word Of The Day