Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 6, 2025
The first that concerns us is the existence of the vaso-motor centre, whose situation and functions have been already described. The second is the localization of the function of thought in the circumvolutions of gray matter on the surface of the cerebral hemispheres fact that we have already assumed to be sufficiently demonstrated.
But if these do not, no facts exist to prove that stimulation of the intellectual functions of the brain is in itself capable of producing vaso-motor paralysis that is, of becoming a cause of hæmorrhage; or, in other words, stimulation of the brain cannot be likened in its effect to galvanic stimulation of a spinal nerve.
This irregularity, marked by vaso-motor spasm, uterine cramp, and pain, represents the lowest degree of disorder, which, if long continued, passes to the next of vaso-motor paralysis, accompanied by excessive hæmorrhage; and finally may, as Dr.
It lowers blood-pressure by paralyzing the vaso-motor centers and by a direct depressant action upon the heart muscle. It diminishes the pulse rate by direct action upon the heart. It lowers the temperature by increasing the loss of heat. It is a powerful antiseptic; and, finally, Its paths of elimination are not known.
I have already explained, in a former number of this Magazine, the nature of the so-called vaso-motor nerves, which preside over the little circular muscles that run round and round in the coats of the blood-vessels. When they are excited, these muscles contract and the size of the arteries is diminished: when they are paralyzed, the arterial inner muscles relax and the vessels dilate.
"Now, it is the result of many observations that the introduction of alcohol specially deranges the vaso-motor system; this derangement showing itself alike in disturbance of the heart's action, and in relaxation of the capillary vessels, which become filled with blood, especially in the nervous system and in the skin.
The brain is not a single organ, but rather a collection of organs, differing from one another in function even more than in situation, and among them only some are really concerned in the production of thought. 2d. In the medulla oblongata exists a nervous centre called the vaso-motor centre, because of its close relations with the vaso-motor nerves.
No experimental proof has hitherto been obtained that stimulation of the cerebral organs lying above the vaso-motor centre, and which include those possessing the function of thought, ever paralyzes this centre; but, as it is only by such paralysis that cerebral conditions can induce dilatation of blood-vessels, it must follow that no experimental proof at present exists that stimulation of the brain ever does cause such dilatation that is, ever does become a cause of hæmorrhage.
Again, the normal influence of the vaso-motor center may be suspended for a time by what is known as the inhibitory or restraining effect. The result is that the tone of the blood-vessels becomes diminished, and their channels widen. The effect of this power of the nervous system is to give it a certain control over the circulation in particular parts.
There are three main varieties: the reflex, the vaso-motor, the toxic. The reflex is by far the most common, and is generally due to irritation from one of the abdominal organs.
Word Of The Day
Others Looking