Nerve Sentence Examples
Her nerve began to frazzle.
Do you know, she had the nerve to call me!
You've got some nerve!
You have a lot of nerve.
They are all pelagic, the foot being entirely transformed into a pair of anterior fins; eyes are absent, and the nerve centres are concentrated on the ven tral side of the oesophagus.
These dorsal eyes are very perfect in elaboration, possessing lens, retinal nerve-end cells, retinal pigment and optic nerve.
Curiously enough, however, they differ from the cephalic Molluscan eye in the fact that, as in the vertebrate eye, the filaments of the optic nerve penetrate the retina, and are connected with the re surfaces of the nerve-end cells nearer the lens instead of with the opposite end.
Hickson and others, that in the bivalves Pecten and Spondylus, which also have eyes upon the mantle quite distinct from typical cephalic eyes, there is the same relationship as in Oncidiidae of the optic nerve to the retinal cells.
The friend, however, lost his nerve and did not throw the dirk.
On account of the shortness of the visceral loop and the proximity of the right visceral ganglion to the oesophageal nerve-ring, the nerve to the osphradium and olfactory ganglion is very long.
AdvertisementHe himself lost his nerve, stammered, nearly fainted, and was dragged out by the soldiers in a state of mental and physical collapse.
In addition to an enormous body of new information chiefly on the shoulder girdle, the alar muscles and the nerve plexuses of birds, this work contained a critical and descriptive summary of practically the whole pre-existing literature on the structure of birds, and it is hardly necessary for the student of ornithology to refer to earlier literature at first hand.
In the Metanemertini, where the longitudinal stems lie inside the muscular body-wall, definite and metamerically placed nerve branches spring from them and divide dichotomously in the different tissues they innervate.
To it belong (a) superficial grooves or deeper slits situated on the integument near the tip of the head, (b) nerve lobes in immediate connexion with the nervous tissue of the brain, and (c) ciliated ducts penetrating into the latter and communicating with the former.
This move on the 14th brought him into touch with Bernadotte, and now a single march forward of all three armies would have absolutely isolated Napoleon from France; but Bernadotte's nerve failed him, for on hearing of Napoleon's threat against Wittenberg he decided to retreat northward, and not all the persuasions of Blucher and Gneisenau could move him.
AdvertisementThere is a special marginal nerve running round the edge of the mantle, but the connexion of this with the rest of the nervous system is not clear; probably it is merely another concentration of the diffused sub-ectodermal nervous fibrils.
The lophophore is supplied by yet a third nerve, the under arm-nerve, which is less clearly defined than the others, and resembles a moderate aggregation of the nerve fibrils, which seem everywhere to underlie the ectoderm, and which in a few cases are gathered up into nerves.
In the middle line the sub-oesophageal nerve mass is small; the ganglion is in fact drawn out into two halves placed on either side of the body.
This has not been demonstrated by an actual following out of the development, but the position of these pieces and the fact that they are (in Limulus) supplied by an independent segmental nerve, favours the view that they may comprise the sternal area of the vanished praegenital somite.
The lateral eyes are in Limulus " compound eyes," that is to say, consist of many lenses placed close together; beneath each lens is a complex of protoplasmic cells, in which the optic nerve terminates.
AdvertisementBut they also receive the nerve fibres of the optic nerve.
It " floats " between the prosomatic nerve centres and the alimentary canal.
In each somite of the mesosoma is a small, free entosternite having a similar position, but below or ventral to the nerve cords, and having a smaller number of muscles attached to it.
It became isolated and detached, why or with what advantage to the organism it is difficult to say, and at that period of Arachnidan development the great ventral nerve cords occupied a more lateral position than they do at present.
We know that such a lateral position of the nerve cords preceded the median position in both Arthropoda and Chaetopoda.
AdvertisementSubsequently to the floating off of the entosternite the approximation of the nerve cords took place in the prosoma, and thus they were able to take up a position below the entosternite.
A very remarkable feature in Limulus, first described by Owen, is the close accompaniment of the prosomatic nerve centres and nerves by arteries, so close indeed that the great ganglion mass and its out-running nerves are actually sunk in or invested by ch.
The loss of an eye will be followed by atrophy of the optic nerve; the tissues in a stump of an amputated limb show atrophic changes; a paralysed limb from long disuse shows much wasting; and one finds at great depths of the sea fishes and marine animals, which have almost completely lost the organs of sight, having been cut off for long ages from the stimuli (light) essential for these organs, and so brought into an atrophic condition from disuse.
There are two closely connected cerebral ganglia, from which arise the usual two pairs of nerve cords.
The leaves are vertical, and arranged in two rows as in the garden flag; they are very thick, stiff and leathery, dark green above, paler below, with the margin and nerve reddishorange.
The oral hood with its cirri has a special nerve supply and musculature by which the cirri can be either spread out, or bent inwards so that those of one side may interdigitate with those of the other, thus completely closing the entrance to the mouth.
The first dorsal spinal nerve coincides in position with the myocomma which separates the first myotome from the second on each side, and thereafter the successive dorsal roots pass through the substance of the myocommata on their way to the skin; they are therefore septal or intersegmental in position.
In 1843, after his removal to Gottingen, he began his great Handworterbuch der Physiologie, mit Riicksicht auf physiologische Pathologie, and brought out the fifth (supplementary) volume in 1852; the only contributions of his own in it were on the sympathetic nerve, nerve-ganglia and nerve-endings, and he modestly disclaimed all merit except as being the organizer.
By first connecting himself with John through his marriage with the English king's daughter Joan, by straining every nerve to repress dissensions and enforce obedience amongst the Welsh chieftains, and later by allying himself with the English barons against his suzerain, this prince during a reign of 44 years was enabled to give a considerable amount of peace and prosperity to his country, which he persistently sought to rule as an independent sovereign, although acknowledging a personal vassalage to the king of England.
The pain is due to stretching of the nerve fibrils or compression of them by the turgid vessels in the swollen tissues.
These probably lessen fever by their action upon the nerve centres which regulate the temperature of the body, and partly by their peripheral action in causing the secretion of sweat.
The nature of this is not very easy to analyse, but as mental depression is closely associated with irritation of the vagus nerve and weakening of the circulation, it seems not at all unlikely that mountain air acts by accelerating the pulse and quickening the circulation, and thus creating a sense of well-being.
A novel substrate of receptor tyrosine phosphatase PTPRO is required for nerve growth factor-induced process outgrowth.
Nerve impulses from the hypothalamus stimulate the posterior pituitary to produce ADH when the osmotic pressure of the blood rises.
Within the brain stem, the signals traveling through the trigeminal nerve reach specialized clusters of neurones called the trigeminal nerve nucleus.
A high-stepped, slapping gait may be the result of a peripheral nerve disease.
It seems that there is a primitive tendency in the Arthropoda for the arteries to accompany the nerve cords, and a " supra-spinal " artery - that is to say, an artery in close relation to the ventral nerve cords--has been described in several cases.
Scorpio certainly comes nearer to Limulus in the high development of its arterial system, and the intimate relation of the anterior aorta and its branches to the nerve centres and great nerves, than does any other Arthropod.
When the trigeminus nerve is divided (Majendie), or when its root is compressed injuriously, say Iby a tubercular tumour, the cornea begins to show points of ulceration, which, increasing in area, may bring about total disintegration of the eyeball.
There seems to be little doubt, notwithstanding, that one of the chief functions of the nerve cell is that of the propagation of a trophicj influence along its axon.
It is much more likely, as Verworn alleges, that the nerves which influence the characteristic function of any tissue regulate thereby the metabolism of the cells in question - in other words, that every nerve serves as a trophic nerve for the tissues it supplies.
A tendency to pigmentation also develops in certain tissues of the body, such as the nerve and muscle cells.
The remarkable discovery of the dual nature of the nervous system, of its duplex development as a lower and upper system of "neurons," has shed much light upon the problems of practical medicine, but this construction is described under Brain; Neuropathology; Muscle And Nerve, &C.
Griesinger (1817-1868), Bevan Lewis - and in the separation from insanity due to primary disease or defect of nerve elements of such diseases as general paralysis of the insane, which probably arise, as we have said, by the action of poisons on contiguous structures - such as blood-vessels and connective elements - and invade the nervous matter secondarily.
He seems to have been well acquainted with the projection of images of objects through small apertures, and to have been the first to show that the arrival of the image of an object at the concave surface of the common nerve - or the retina - corresponds with the passage of light from an object through an aperture in a darkened place, from which it falls upon a surface facing the aperture.
A, Fasciola hepatica, from the ventral surface (X 2); the alimentary and nervous systems only shown on the left side of the figure, the excretory only on the right; a, right main branch of the intestine; c, a diverticulum; g, lateral ganglion; n, lateral nerve; o, mouth; p, pharynx; s, ventral sucker; cs, cirrus sac; d, left anterior dorsal excretory vessel; m, main vessel; v, left anterior ventral trunk; x, excretory pore.
The cerebral cortex, and, more definitely, the cortical elements (nerve cells), formed the seat of the activity of the soul, and were ordered into departments according to various functions.
The nervous system consists of a ganglion or brain, which lies dorsally about the level of the junction of the pharynx and the stomach, a nerve ring and a segmented neutral cord.
The prey is sometimes stung in the neighbourhood of the nerve ganglia, so that it is paralysed but not killed, the grub of the fossorial wasp devouring its victim alive; but this instinct varies in perfection, and in many cases the larva flourishes equally whether its prey be killed or not.
The progress of thought may show it to be, in truth, relative, as when the nerve of Hume's scepticism is shown to be his thoroughgoing empiricism, or when the scepticism of the Critique of Pure Reason is traced to the unwarrantable assumption of things-in-themselves.
The eyes are refractive globules set in a cup of red pigment traversed by a nerve fibre, and lie on the proximal side of the body, directly on the postero-dorsal surface of the brain, or at a little distance from it, on the neck, often within the circle on the corona, and usually well within the transparent body.
It bears a group of long setose hairs the bases of which are connected with the nerve fibre.
The nerve ganglion is formed by an ingrowth of epiblast, and so are the pedal glands.
The extraing to foot of rotifers; at, median blastoporic opening of antenna, united by a nerve to br, brain the cloaca leads us to a (letter omitted in B); bl, bladder, re ver y different view, which ceiving ramified kidney in B, C, D; finds negative support f, foot, and f.g, its cement-gland;.
He was able to maintain his strenuous habits of study till he reached the advanced age of seventy-two, when he was, forced, by paralysis of the optic nerve, to give up work almost.
Near the base of the ctenidium is a patch of sensory epithelium innervated from the branchial nerve, forming a sense-organ called the osphradium, whose function is to test the water entering the branchial cavity.
Pedal and pleural on each side are connected by a pleuro-pedal connective Each pleural ganglion gives off a long nerve which supplies the viscera, and the two unite posteriorly below the intestine.
Some years ago, when for instance the Ohio and Indiana elections were held a few weeks before the general election, each party strained every nerve to carry them, for the sake of prestige and the influence on other states.
The terminals of the vagus nerve are also stimulated, causing the heart to beat more slowly.
He agrees with Fechner that physical process of nerve and psychical process of mind are really the same psychophysical process as appearing on the one hand to an observer and on the other hand to one's own consciousness; and that physical phenomena only produce physical phenomena, so that those materialists and realists are wrong who say that physical stimuli produce sensations.
The cerebral ganglion also gives off a nerve on each side to a pair of small ganglia, united by a median commissure, which have sunk into and control the muscles of the head.
It is thought to depend upon some connexion, not yet anatomically demonstrated, between the third cranial nerve and its nucleus in the floor of the iter and the substantia nigra.
He strained every nerve to induce his clergy to accept his ruling on the questions of the reservation of the Sacrament and of the ceremonial use of incense in accordance with the archbishop's judgment in the Lincoln case; but when, during his last illness, a prosecutor brought proceedings against the clergy of five recalcitrant churches, the bishop, on the advice of his archdeacons, interposed his veto.
The body is composed of a large number of segments; the prostomium bears a pair of tentacles; the nervous system consists of a brain and longitudinal ventral nerve cords closely connected with the epidermis (without distinct ganglia), widely separated in Saccocirrus, closely approximated in Protodrilus, fused together in Polygordius; the coelom is well developed, the septa are distinct, and the dorsal and ventral longitudinal mesenteries are complete; the nephridia are simple, and open into the coelom.
It resembles Dinophilus in the possession of a ventral pharyngeal pouch (which bears teeth in Histriodrilus only), the small number of segments, and absence of distinct septa, the absence of a vascular system, the presence of distinct ganglia on the ventral nerve cords, and of small nephridia which do not appear to open internally.
Among the properties of living material there is one, widely though not universally present in it, which forms the pre-eminent characteristic of 1 The anatomy of the muscles is dealt with under Muscular System, and of the nerves under Nerve and Nervous System.
In several of these it appears not unlikely that the recurrent explosive liberations of energy in the muscle tissue are not secondary to recurrent explosions in nerve cells, but are attributable to decompositions arising sua sponte in the chemical substances of the muscle cells themselves in the course of their living.
In these the rhythmic activity is, however, clearly secondary to rhythmic discharges of the nerve cells constituting the respiratory centre in the bulb.
Such discharges descend the nerve fibres of the spinal cord, and through the intermediation of various spinal nerve cells excite the respiratory muscles through their motor nerves.
They are, however, less excitable than are the nerve cells which innervate them.
Just as in a nerve fibre, when excited by a localized stimulus, the excited state spreads from the excited point to the adjacent unexcited ones, so in muscle the "contraction," when excited at a point, spreads to the adjacent uncontracted parts.
Both in muscle and in nerve this spread is termed conduction.
Non-myelinate nerve fibres are as resistant to fatigue as are the myelinate.
The work of Camillo Golgi (Pavia, 1885 and onwards) on the minute structure of the nervous system has led to great alteration of doctrine in neural physi nerve cells, that is to say, the fine nerve fibres - since all nerve fibres are nerve cell branches, and all nerve cell branches are nerve fibres - which form a close felt-work in the nervous centres, there combined into a network actually continuous throughout.
Each neuron or nerve cell is a morphologically distinct and discrete unit connected functionally but not structurally with its neighbours, and leading its own life independently of the destiny of its neighbours.
But when neurons are linked together it is found that nerve impulses will only pass from neuron A to neuron B, and not from neuron B to neuron A; that is, the transmission of the excited state or nervous impulse, although possible in each neuron both up and down its own cell branches, is possible from one nerve cell to another in one direction only.
That direction is the direction in which the nerve impulses flow under the conditions of natural life.
The synapse, therefore, as the place of meeting of one neuron with the next is called, is said to valve the nerve circuits.
The axons of the motor neurons are, inasmuch as they are nerve fibres in nerve trunks, easily accessible to artificial stimuli.
The inference is that the "fatigue substances" generated in the muscle fibres in the course of their prolonged contraction injure and paralyse the motor end plates, which are places of synapsis between nerve cell and muscle cell, even earlier than they harm the contractility of the muscle fibres themselves.
The alkaloid curarin causes motor paralysis by attacking in a selective way this junction of motor nerve cell and striped muscular fibre.
On the other hand, in some neurons, after severance of the axon from the rest of the cell (spinal motor cell), the whole nerve cell as well as the severed axon degenerates, and may eventually die and be removed.
In the severed axon the degeneration is first evident in a breaking down of the naked nerve filaments of the motor end plate.
This death of the sheath as well as of the axis cylinder shows that it, like the axis cylinder, is a part of the nerve cell itself.
When, for instance, the axons of the ganglion cells of the retina are severed by section of the optic nerve, and thus their influence upon the nerve cells of the visual cerebral centres is set aside, the nerve cells of those centres undergo secondary atrophy (Gadden's atrophy).
Similarly, when the axons of the motor spinal cells are by severance of the nerve trunk of a muscle broken through, the muscle cells undergo "degeneration" - dwindle, become fatty, and alter almost beyond recognition.
This trophic influence which one neuron exerts upon others, or upon the cells of an extrinsic tissue, such as muscle, is exerted in that direction which is the one normally taken by the natural nerve impulses.
It seems, especially in the case of the nexus between certain neurons, that the influence, loss of which endangers nutrition, is associated with the occurrence of something more than merely the nervous impulses awakened from time to time in the leading nerve cell.
A continuous lesser "change" or stream of changes sets through the neuron, and is distributed by it to other neurons in the same direction and by the same synapses as are its nerve impulses.
In tracing the tonus of neurons to a source, one is always led link by link against the current of nerve force - so to say, "up stream" - to the first beginnings of the chain of neurons in the sensifacient surfaces of the body.
These muscles exhibit a certain constant condition of slight contraction, which disappears on severance of the nerve that innervates the muscle.
Stretching of the muscles antagonistic to the extensors - namely, of the flexor muscles - reduces the jerk by inhibiting the extensor spinal nerve cells through the nervous impulses generated by the tense flexor muscles.
Exner first showed, many years ago, that the nerve impulse travels through the spinal ganglion at the same speed as along the other parts of the nerve trunk - that is, that it suffers no delay in transit through the perikarya of the afferent rootneurons.
In the myelinated cell branches of the neuron, that is, in the ordinary nerve fibres, no visible change has ever been demonstrated as the result of any normal activity, however great - a striking contrast to the observations obtained on the perikarya.
The chemical changes that accompany activity in the nerve fibre must be very small, for the production of CO 2 is barely measurable, and no production of heat is observable as the result of the most forced tetanic activity.
This is the explanation of the repair of nerve trunks that have been severed, with consequent degeneration of the peripheral nerve fibres.
As a rule, a longer time is required to restore the motor than the sensory functions of a nerve trunk.
At the beginning of its history each is unprovided with myelinate nerve fibres.
Examination of the cerebellum by the method of Wallerian degeneration has shown that a large number of spinal and bulbar nerve cells send branches up into it.
It has been suggested that the gradual cumulative result of the activity of the nerve cells during the waking day is to load the brain tissue with "fatigue-substances" Theories of which clog the action of the cells, and thus periodi cally produce that loss of consciousness, &c., which is sleep. Such a drugging of tissue by its own excreta is known in muscular fatigue, but the fact that the depth of sleep progressively increases for an hour and more after its onset prevents complete explanation of sleep on similar lines.
The nerve cell just prior to sleep is still well capable of response to stimuli, although perhaps the threshold-value of the stimulus has become rather high, whereas after entrance upon sleep and continuance of sleep for several hours, and more, when all spur to the dissimilation process has been long withheld, the threshold-value of the sensory stimulus becomes enormously higher than before.
The long-continued incitement to catabolism of the waking day thus of itself predisposes the nerve cells towards rebound into the opposite phase; the increased catabolism due to the day's stimuli induces increase of anabolism, and though recuperation goes on to a large extent during the day itself, the recuperative process is slower than, and lags behind, the disintegrative.
The physical "touch" that initiates the psychical "touch" initiates, through the very same nerve channels, a reflex movement responsive to the physical "touch," just as the psychical "touch" may be considered also a response to the same physical event.
This latter result is due to paralysis of the chorda tympani nerve, which is mainly responsible for the salivary secretion.
Certain nerve fibres from the sympathetic nervous system, which can also cause the secretion of a (specially viscous) saliva, are entirely unaffected by atropine.
This can be experimentally shown - by the method of exclusion - to be caused by a paralysis of the terminals of the third cranial nerve in the sphincter pupillae of the iris.
Professor Schafer recommended the use of atropine prior to the administration of a general anaesthetic, in cases where the action of the vagus nerve upon the heart is to be dreaded; and there is little doubt of the value of this precaution, which has no attendant disadvantages, in all such cases.
Fusel oil and its chief constituent, amyl alcohol, are direct nerve poisons.
A difference in calibre, elasticity or branching of a blood vessel, the smallest variation in a nerve or group of vessel-cells, any anatomical or physiological divergence, is reflected throughout the organism.
Again, so long as we keep to the syllogism as complete in itself and without reference to its place in the great structure of knowledge, the nerve of proof cannot be conceived in other than a formal manner.
The nerve of proof in the processes by which he establishes causal conjunctions of unlimited application is naturally thought to lie in the special canons of the several processes and the axioms of universal and uniform causation which form their background.
The exponent of logic as metaphysic, for whom the rational is the real is necessarily in revolt against all that is characteristically Kantian in the theory of knowledge, against the transcendental method itself and against the doctrine of limits which constitutes the nerve of " criticism."
Augustus, however, was now seventytwo, the Dalmatian outbreak had severely tried his nerve, and now for the second time in three years the fates seemed to pronounce clearly against a further prosecution of his long-cherished scheme of a Roman Germany reaching to the Elbe.
This cord is neither elastic nor solid, but consists of nerve tissue, fibres and ganglion cells, surrounding a small central canal.
This strict definition, if adhered to, however, would not be applicable to a large number of cases of neuralgia; for in not a few instances the pain is connected with some source of irritation, by pressure or otherwise, in the course of the affected nerve; and hence the word is generally used to indicate pain affecting a particular nerve or its branches from any cause.
Any strain upon the nervous system, such as mental overwork or anxiety, is a potent cause; or exposure to cold and damp, which seems to excite irritation in a nerve already predisposed to suffer.
But irritation may be produced by numerous other causes besides this - such as a decayed tooth, diseased bone, local inflammations in which nerves are implicated, by some source of pressure upon a nerve trunk, or by swelling of its sheath in its passage through a bony canal or at its exit upon the surface.
Various forms of perverted nerve function may be found co-existing with or following neuralgia.
Facial neuralgia, or tic douloureux, affects the great nerve of sensation of the face (fifth nerve), and may occur in one or more of the three divisions in which the nerve is distributed.
When the first or upper division of the nerve is involved the pain is mostly felt in the forehead and side of the head.
When the second division of the nerve is affected the pain is chiefly in the cheek and upper jaw, the painful points being immediately below the lower eyelid, over the cheek bone, and about the upper lip. When the third division of the nerve suffers the pain affects the lower jaw, and the chief painful points are in front of the ear and about the chin.
The specially painful points are chiefly at the commencement of the nerve as it issues from the spinal canal, and at the extremities towards the front of the body, where it breaks up into filaments which ramify in the skin.
It affects the great sciatic nerve which emerges from the pelvis and runs down the leg to the foot.
It is in most instances traceable to exposure to cold or damp, to overuse of the limbs in walking, &c. Any source of pressure upon the nerve within the pelvis, such as may be produced by a tumour or even by constipation of the bowels, may excite an attack of sciatica.
In general the nerve of one side only is affected.
The pain which is felt at first a little behind the hip-joint steadily increases in severity and extends along the course of the nerve and its branches in many instances as far as the toes.
The plan at one time resorted to of dividing or excising a portion of the affected nerve is now seldom employed, but the operation of nerve-stretching in some forms of neuralgia, notably sciatica, is sometimes successful.
It consists in cutting down upon and exposing the nerve, and in seizing hold and drawing upon it so as to stretch it.
Thus in diphtheria changes in both nerve cells and nerve fibres have been found, and in tetanus minute alterations in the nucleus and protoplasm of nerve cells.
There is therefore strong evidence that antitoxin molecules do exist as part of the living substance of nerve cells.
The separate nervecentres are, as a rule, placed in communication only by the general nerve-plexus, but in Charybdaea there is a zigzag marginal nerve connecting them up.
Close to each cerebral ganglion is a pleural ganglion, and each is connected by a long nerve with the pedal ganglion of the same side, the two connectives of either side being united in the distal part of their course.
The nervous system consists of a circumoesophageal nerve, with scarcely differ entiated brain, joining below a large ganglionic mass no doubt representing many fused ganglia (B).
It is of thin membranous consistence, usually obtuse, often bifid, and possesses no central rib or nerve, but has two lateral ones, one on either side; the margins are frequently folded in at the ribs, which thus become placed at the sharp angles.
Its most effective use, however, is as a nerve tonic in paralysis agitans, locomotor ataxia, impotence and nervous exhaustion.
He discovered that in the nervous trunks there are special sensory filaments, the office of which is to transmit impressions from the periphery of the body to the sensorium, and special motor filaments which convey motor impressions from the brain or other nerve centre to the muscles.
He also demonstrated that no motor nerve ever passes through a ganglion.
Beneath each food-groove was a radial water-vessel and probably a nerve and blood-vessel, all which structures passed either between certain regularly arranged thecal plates, or along a furrow floored by those plates, which were then in two alternating series.
But Richardwho showed astounding nerve and presence of mind for a lad of fourteencantered up to them shouting that he would be their chief and captain.
In other instances, notably in the lemurs, but also in certain carnivora, rodents and marsupials, they occupy a position on the fore-arm near the wrist, in connexion with glands, and receive sensory powers from the radial nerve.
McClellan, charging him with incompetency and lack of "nerve."
In the heating operation the surface is charred, and thereby the pores are closed up, and what is termed "nerve" is given to the material.
Here he stated the principle, not before recognized, that the kind of sensation following stimulation of a sensory nerve does not depend on the mode of stimulation but upon the nature of the sense-organ.
Thus light, pressure, or mechanical stimulation acting on the retina and optic nerve invariably produces luminous impressions.
The similarity of the symptoms to those of cholera is very marked, but if the suspicion arises it can soon be cleared up by examining any of the secretions for arsenic. More rarely the poison seems to centre itself on the nerve centres, and gastro-intestinal symptoms may be almost or quite absent.
This case arises when the visual angle, under which the object appears, is approximately a minute of arc; it is due to the physiological construction of the retina, for the ends of nerve fibres, which receive the impression of light, have themselves a definite size.
The explanation generally given is that the nerve and other cells become accustomed to the drug, so that they cease to react, or that an antitoxin is formed which antagonizes the poison, or that the poison is rapidly destroyed in the body.
All of them injected into the blood in large doses act as muscle and nerve poisons, and during their excretion by the kidney usually irritate it severely, but only a few are absorbed in sufficient amount to produce similar effects when given by the mouth.
In large doses they are powerful nerve poisons, but as usually taken they exercise a gently stimulant effect upon the nervous system.
Aconitine, delphinine and many of their derivatives have a very widespread depressing action on muscle and nerve.
Hydrocyanic acid is a general protoplasmic poison, all the lower organisms being very susceptible to its action, while in the higher animals it speedily depresses or paralyses all forms of nerve tissue.
Where did he get the nerve to call Giddon a jerk, after hiding behind her?
Although, lately she had been hitting that nerve with little or no effort.
Someone had the utter nerve to maim me who didn't even have a gun!
The demon lord bristled visibly for a split second, long enough to tell her she hit a nerve.
He didn't know what nerve he hit, but he'd hit something.
The bastard had the nerve to ask me to climb with him.
And he has the nerve to call this shit exciting and romantic!
Someone grabbed the dough and Dean didn't believe Baratto or the twins had either the brains or nerve to pull off a heist like that, much less stay mum about it for months.
Alex knew how to make every nerve in her body ache for him.
He has bilateral optic nerve atrophy, which affects the visual information passing from the eye to the brain.
The junction shown in figure 1 is of a nerve that releases acetylcholine.
Terminal nerve fibers release acetylcholine into the neuromuscular junction, which then binds to acetylcholine receptors on muscle cells.
Sarin is the nerve agent that was later used in the terrorist attack on the Tokyo underground in 1995.
Nerve agents are powerful; they require powerful antidotes to keep the victim alive.
In America, animal tests conducted with a mixture of a nerve gas antidote and insect repellent indicated nerve damage.
This case had fore and hind limb ataxia but normal cranial nerve function.
The drug atropine inhibits the parasympathetic nerve, causing the pupil to dilate.
They work by electrically stimulating the auditory nerve (nerve of hearing ).
The motor nerve cell body has a long fiber called an axon, which extends from the central nervous system to the muscles.
The cell body of a sensory nerve has two axons.
Gray matter contains nerve cell bodies and unmyelinated axons.
A single long axon carries the nerve impulse away from the cell body.
Some branchial motor axons travel with the inferior alveolar nerve.
Nerves These are made up of bundles of nerve cell axons.
John O'Neill should be well known to Nerve readers, having provided the breathtaking backdrops for our last two covers.
No attack materialized, and during Sunday there was increasing bewilderment and loss of nerve.
Your vet may be able to perform temporary nerve blocks to see if an anesthetic can temporarily stop the headshaking.
Digital nerve blockade is simple and easy to perform and provides useful analgesia for a variety of minor surgical procedures.
Will they have the nerve to tell you that you have a huge bogie under your nose?
The problem is that only 0.2% of the damaged nerve cells are replaced.
McTimoney chiropractic aims to restore nerve function in order to promote natural health.
They are nerve poisons, inhibiting the enzyme cholinesterase, which can have severe effects on the central nervous system.
Numerous chemical and biological phenomena are modeled by non-linear ODE's, for example chemical reactions and voltage clamped nerve cells.
Digoxin also acts indirectly by increasing parasympathetic activity via the vagus nerve, further slowing atrioventricular node conduction.
Asked how nerve conduction studies work at which point bell went thank goodness.
Local anesthetic agents may be administered intradermally or subcutaneously to block impulse conduction in local nerve fibers.
The two hemispheres communicate via dense bundles of nerve fibers called the corpus callosum.
This is when a small muscle in the ear, which is also controlled by the 7th cranial nerve, stops working temporarily too.
Cranial nerve palsies of the third, fourth and sixth cranial nerve palsies of the third, fourth and sixth cranial nerves may occur, affecting extraocular motility.
The trigeminal nerve is exposed by performing a craniotomy (small hole in the skull behind the ear ).
The Schwann cell has an extensive cytoplasm which allows it to wrap a myelin sheath around nerve axons.
Microvascular decompression treats the cause of the disease without inducing nerve damage.
In cases where there has been trauma, facial nerve decompression may be justified.
The narrowing of the hole is detected by a nerve cell dendrite which projects into it, producing an electric signal.
The most frequently involved cranial nerve dermatome is the ophthalmic division of the trigeminal nerve.
Reflexology is a system of healthcare that works by stimulating the many nerve endings in the feet.
These nerve endings or ' reflex points ' are related to various zones of the body.
Orthoptic findings included concomitant esotropia, sixth, third and fourth nerve palsies.
This is normally prevented by a tiny messenger substance known as " GABA " which makes the nerve cells less excitable.
This causes the membrane potential to become more negative and results in muscle and nerve cells becoming less excitable.
The superior and inferior longitudinal muscles each had an average of 40 distinct muscle fascicles, each supplied by a nerve branch.
New branches of the remaining nerve cells were sent out to adopt the orphaned muscle fibers.
This large nerve exits the pelvis through the greater sciatic foramen to enter the gluteal region - more info.
Several branchial motor nerves are also given off as the mandibular nerve enters the infratemporal fossa.
Other people believe that the virus only resides within the nerve ganglion, which is further away from the skin.
Carmen is an expert horsewoman and held her nerve admirably when it mattered.
Some people may know the visual side alone as optic nerve hypoplasia.
This antibody, also called an immunoglobulin, may damage the nerve fibers.
Auditory brainstem implants have been used for adults who have suffered trauma to their hearing nerve which means that it is no longer useful.
Failure to transmit nerve impulses ultimately results in paralysis of the louse.
Intention is a powerful force; it begins to activate the nervous system and triggers nerve impulses into muscles.
The nerve impulses cause the muscles to contract, thus narrowing the airway.
In other words, the high- intensity training allowed nerve cells to ' reach out and touch ' an increased number of muscle fibers.
Mechanism - narrowing causes spinal nerve root irritation with referred pain in the arm or leg.
The place where muscle and nerve meet is called a ' neuromuscular junction ' (NJ ).
Soya foods naturally containing lecithin, which is an excellent nerve building food, will also help.
The nerve travels to the thigh by passing under or through the inguinal ligament in its own tunnel.
Anatomy The ulnar nerve travels with the ulnar artery in the tunnel of Guyon, covered by the transverse carpal ligament.
Make sure your daughter gets a pain med that treats nerve pain.
The sciatic nerve is most likely to lie slightly medial to the path of the needle if these landmarks are used.
In 1821, he published his anatomic diagrams of the course of the facial nerve and its innervation of the facial musculature.
At the site of a lesion, a nerve insulating material, called myelin, is lost.
In contrast to adult dogs, juvenile dogs appeared to be more sensitive to peripheral nerve lesions as compared to skeletal myopathy.
From here, the ' sound message ' is passed along the auditory nerve to the brain.
However, the term also covers nerve conduction studies - testing the electrical function of nerve conduction studies - testing the electrical function of nerves in the limbs.
The optic nerve is made up of thousands of nerve fibers.
The vagus nerve is used to slow down the heart.
Potential news reports of soldiers writhing in agony from a cloud of sarin nerve gas had spooked the president and his commanders.
The protein that is produced protects these mature nerve cells from death following an injury.
The precise function of the gene is unknown, although it is thought to help nerve cells communicate with each other.
Sensory nerve cells carry information about muscle tension and body position to motor nerve cells in the spinal cord to control muscle contraction.
Using rats, scientists showed that a damaged area in the brain - akin to human stroke - is infiltrated by new nerve cells.
Despite the large number of the optic nerve fibers their capacity of plasticity for to achieve recovery is rather limited.
The autonomic nerve fibers which radiate from the central nervous system to the ganglia of the autonomic nervous system are called preganglionic nerves.
These chlorinated hydrocarbons work mainly by blocking nerve impulses necessary for normal bodily functions.
Calcium also helps conduct nerve impulses, regulate your heartbeat, and maintain cell membranes.
Cutting the balance nerve in an operation called vestibular neurectomy.
One type of nerve problem arising in the forefoot is called a neuroma.
Similar nerve conduction results Studies show a " mild background demyelinating neuropathy " .
Click here to read our factsheet on nerve damage due to diabetes, called diabetic neuropathy.
Finally the motor nerve fibers may be affected on their own, producing a pure motor neuropathy.
Physiological Properties of TTX TTX is an especially potent neurotoxin, specifically blocking voltage-gated sodium channels on the surface of nerve membranes.
The first nerve cell communicates with the next by releasing neurotransmitters into the synapse.
And the simple vein will receive nourishment from itself, and the nerve and artery from the vein.
Local Anesthetic Techniques Pudendal Nerve Block This is usually performed by the obstetrician using a vaginal approach.
The joined up path that signals travel down from retina to optic nerve then optic chiasm then occipital lobe is called the visual pathway.
Replicate high-density rat genome oligonucleotide microarrays reveal hundreds of regulated genes in the dorsal root ganglion after peripheral nerve injury.
The mice fed the drug cocktail lived substantially longer, and had a delayed onset of nerve and muscle deterioration.
A really high pressure will damage the optic nerve immediately.
In the visual pathway the fibers of the retinal ganglion cells form the optic nerve.
The left optic nerve also enhanced (not shown ).
The anesthetic is placed just as the nerve loops into the canal orifice.
Fourth nerve palsy was the most commonly affected nerve.
Symptoms of nerve root pressure paralysis of single muscles, possibly with pain radiating to the arms or legs.
Water tends to move along the easiest route available which, in the brain, is along the major nerve pathways.
Peripheral nerve block using phenol is a relatively old technique.
The chakras are associated with particular nerve plexuses in the physical body.
It also has the effect of improving joint proprioception (i.e. feedback to the muscles from the nerve endings in the joint ).
Endoscopic orbital decompression may be used to treat disfiguring proptosis or sight threatening optic nerve compression in patients with thyroid eye disease.
Be protesting with had hit a nerve horse racing pundit.
A vesicular rash restricted to the distribution of a single sensory nerve is the classic skin lesion of shingles.
Reassess risk factors for serious pathology (see red flags ). Reassess presence of nerve root pain.
Significantly more sciatic nerve axons regenerated in the exercised animals than the sedentary animals.
We can also understand that when Redwood slashes through the nerve of European regionalism in Wales, he is striking at European Union itself.
In addition Dong Quai acts as a nerve and smooth muscle relaxant, has pain-relieving properties and is a circulatory stimulant.
Anatomy The posterior tibial nerve runs just behind the inside ankle bone in a tunnel covered by the flexor retinaculum.
This was causing pressure on the nerve root causing loss of myelin sheath.
A nerve cell contains a high concentration of potassium salt whilst the chemical composition outside the cell membrane is higher in sodium salt.
Another 6,454 of these rockets filled with the deadly nerve agent sarin were accounted for and destroyed by inspectors between 1992 and 1993.
One teaspoon of the nerve agent sarin can cause up to 10,000 deaths.
The British military had been testing the nerve gas sarin on thousands of young servicemen.
Nerve injury sciatic Nerve Thirty percent of acetabular fractures have associated sciatic nerve injury.
Another well-known Mercury ruled planet, Valerian, has been used as a nerve sedative for centuries.
Damaged nerve tissue Any of these may be warning signs that eye disease could develop.
If the PFM, urinary sphincters or nerve supply are impaired a loss of continence may occur.
When using frames that support the anterior superior iliac spines, the lateral cutaneous nerve of the thigh may be compressed and stretched.
All these diseases resulted in parts of the brain becoming spongy the nerve cells replaced by holes.
Nerve Root Blocks may be more useful for Foraminal stenosis.
Depending on any prescribed drugs being taken, nerve stimulants may also be appropriate in the short term.
It is involved in the formation of certain hormones and nerve regulating substances, and is particularly supportive of the adrenal glands.
It isn't clear that people with neuromuscular diseases are unusually susceptible to the nerve or muscle damaging effects of statins.
Pain fibers produce substance P, in order for the pain signal to cross the nerve synapse.
Explain nerve to nerve synapses, during a specific body movement.
Some twenty thousand Iranians were killed by mustard gas, and the nerve agents tabun and sarin, all of which Iraq still possesses.
Neuroma - a fibrous thickening of a nerve caused by reaction to long-standing irritation.
Over a period of time, oats can act as a nerve tonic, reducing stress and aiding relaxation.
It was touching as few TV shows can be, in that it touched a nerve few would see as vulnerable.
The first algorithm is for diagnostic triage, which includes red flags for possible serious spinal pathology and nerve root problems.
The inner wall of the vesicle (region of closure) is frequently thickened to form a so-called " sensecushion," apparently a ganglionic offshoot from the sub-umbral nerve - ring.
All tadpoles are provided with more or less distinct lines of muciferous sensory crypts or canals, which stand in immediate relation to the nerve branches and are regarded as organs of a special sense possessed by aquatic vertebrates, feeling, in its broadest sense, having been admitted as their possible use, and the function of determining waves of vibration in the aqueous medium having been suggested.
The brachial plexus is formed by four or five of the lowest cervical nerves; the last nerve of this plexus often marks the boundary of the cervical and thoracic vertebrae.
To begin with, Pasteur, in studying the malady in dogs, came to the conclusion that the virus had its seat in the nerve centres, and he proved that the injection of a portion of the matter of the spinal column of a rabid dog into the body of a healthy one produces in the latter with certainty the symptoms of rabies.
A special " sympathetic " system arises by paired nerves from the oesophageal connectives; these nerves unite, and send back a median recurrent nerve associated with ganglia on the gullet and crop, whence proceed cords to various parts of the digestive system.
The earliest interpretation put upon this experiment was that the trophic influence of the nerve having been withdrawn, the tissue failed to nourish itself, and that degeneration ensued as a consequence.
It is this wide range of dynamic peculiarities above the common range of known physical and chemical molecules which excites our wonder; and a reflection of these peculiar properties is seen in their affinities for this or that toxic or constructive agent, whereby the peculiarity, for example, of a particular kind of nerve cell may be altered, antagonized, reinforced or converted.
It has been urged that the neurons retract during sleep, and that thus at the synapses the gap between nerve cell and nerve cell becomes wider, or that the supporting cells expand between the nerve cells and tend to isolate the latter one from the other.
But very often refreshment is undoubtedly obtained from such narcotic sleep. It may be supposed that in the latter case the effect of the drug has been to ensure occurrence of that second predisposing factor mentioned above, of that withdrawal of sense impulses from the nerve centres that serves to usher in the state of sleep. In certain conditions it may be well worth while by means of narcotic drugs to close the portals of the senses for the sake of thus obtaining stillness in the chambers of the mind; their enforced quietude may induce a period in which natural rest and repair continue long after the initial unnatural arrest of vitality due to the drug itself has passed away.
Herein are demanded the eye and the nerve.
Every nerve was strained and quivering with excitement, and in every chamber was a round of ammunition waiting.
Reassess risk factors for serious pathology (see red flags). Reassess presence of nerve root pain.
Nerve Relaxants are herbs that quickly calm the person to a state where the body and mind becomes relaxed.
The sect released sarin nerve gas at numerous points on the Tokyo subway, affecting a distance of more than eight miles.
Yesterday, as I expected - weaponised sarin nerve agent and mustard gas finally have been found in Iraq.
For knee replacement, a 3-in-1 block combined with a sciatic nerve block can be effective.
Nerve Injury Sciatic Nerve Thirty percent of acetabular fractures have associated sciatic nerve injury.
Sedated patients must still be able to communicate with the operator during the nerve block procedure.
These effects are caused by the shingles virus affecting the nerve during the early stage of the illness.
As a result muscles which are commanded by the nerve cells in these areas of the spinal cord become affected.
It aims to reduce the sensitivity of the nerve endings in the spinal cord in order to close the pain ' gates '.
But launching big is a risky business, demanding a steely nerve.
Nerve Root Blocks may be more useful for Foraminal Stenosis.
On the right hand side, the nerve passes behind the vagus and loops around the subclavian artery.
The presence of the posterior interosseous nerve in the substance of the supinator muscle is of paramount importance.
Its relation to sural nerve & its root value, effects of damage.
Sural nerve biopsies from six affected individuals and the post-mortem findings in 1 case showed mainly axonal loss.
Stripping of the SSV is performed less frequently as it is associated with a significant risk of sural nerve damage.
It is n't clear that people with neuromuscular diseases are unusually susceptible to the nerve or muscle damaging effects of statins.
Running up the spiral is row of exquisitely sensitive ' hair cells ' which synapse with the neurones of the cochlear nerve.
The nerve roots appear thickened and clumped together and lie around the periphery of the theca interna in the lower lumbar canal.
How you have the nerve to finish your tirade of hate with best wishes I do not understand.
The result is that the transmission of nerve impulses through neural networks becomes modified.
Acetyl choline One of the naturally occurring chemicals that transmits impulses from one nerve to another.
From there, the trigeminal nerve root continues back toward the side of the brain stem, and inserts into the pons.
Described the features & immediately went on to say that I thought this was a low ulna nerve palsy because...
The median reduction of seizures from vagal nerve stimulation is 45% at 1 year.
Lucky ones died due to pressure on the vagal nerve.
He also has a vagus nerve stimulator implant that he thought might be affected by any radiation from a computer.
From the vagus nerve the signals travel up into the areas of the brain thought to be involved in causing seizures.
The cost of vagus nerve stimulation is about £ 105 75 per person per year.
Keep in mind that the more nerve connections your baby makes, the stronger his brain will become, so educational stimulation is important.
While some people mistakenly believe that cerebral palsy involves muscular or nerve problems, it is actually a brain disorder in which the brain is unable to effectively control the body's movements.
The action of the muscles is directed by nerve impulses.
Cayenne works by changing the focus of the nerve endings and then blocking the nerve signals.
Cayenne is being used to treat sensory nerve fiber disorders that occur with arthritis, psoriasis and other inflammatory conditions in the body.
Many Christians will find dating sites such as Nerve or Adult Friend Finder inappropriate for their needs.
Merck offers an impressive collection of information on various disorders, including cancer, digestive disorders, nerve disorders and much more.
Also, given the fact that some skiers need a little liquid courage to get up the nerve to strip down, their judgment can be further impaired.
Skullcap is a sedative and helps treat nerve disorders.
If a threat is especially severe or recurs frequently, such as protracted combat or living with abuse, the chemicals that carry messages from one nerve cell to another become depleted, and the brain becomes sluggish and inefficient.
When the nerve impulses send the signals to your brain, it is unable to tell the difference of an imagined or real situation or occurrence.
Figuring out how to ask a girl to prom can be a scary, nerve wrecking experience.
One of the eight B vitamins, vitamin B12 is a water-soluble vitamin that aids in the healthy maintenance of nerve cells and red blood cells.
As a result, anemia or nerve damage can be present without being diagnosed.
However, be aware that while folic acid can correct anemia, it cannot reverse nerve damage caused by a B12 deficiency.
Since red blood cells give you energy and stabilize nerve function, the symptoms of both anemia and depression will fade and eventually cease.
I remember canoeing with my fiancée and it took all day to get up the nerve for a quick peck.
Serotonin is a chemical in the brain that sends electrical signals to and from nerve cells.
St. John's Wort is used by many to treat mental disorders, nerve pain, anxiety, sleep disorders, and depression.
It was fun, but a little nerve wracking.
If it's not his ears, he may have a gum infection that has worked it's way through to the sinus nerve above the tooth.
The impulses travel to the body systems through electrical impulses transferred through nerve fibers.
Neuro-hormonal responses cause nerve stimulation, increase circulation, and create the release of endorphins and cortisol.
The various minerals, vitamins and carbohydrates provide many essential health benefits such as more energy, healthy immune system, strong bones and improved nerve function.
Esteban's early career was cut short by an accident that left him with nerve damage to his left hand and an eye that was overly sensitive to the light.
Each of these substances is considered to be a nerve gas and can be deadly.
This is a rare medical condition where the affected individual's own nervous system goes into overdrive and starts attacking the nerve cells.
One of the leading causes of vision loss among senior citizens is the progressive, irreversible damage caused to the optic nerve by glaucoma.
Treatments may help either cognitive or behavioral symptoms by working on emotional centers in the brain or improving the activity of nerve cells to help inhibit cognitive decline.
This symptom, while startling, may be caused by fluctuating hormones affecting the nerve tissue.
As scientists have since learned, motor and cognitive skills deteriorate as brain cells and connections between nerve cells die.
When exposed to light, the retina sends a message through the nerve pathway to the brain to let you know it is time to wake up.
Narcolepsy is thought to be caused by abnormalities in the structure and the function of nerve cells in the brain.
If you sleep on an arm or bend your wrist wrong while asleep, you can cut off the nerve sensation and experience 'hand or hands asleep' feeling.
Carpal tunnel syndrome occurs when you experience nerve damage to the median nerve that runs through your wrist joints.
Sleeping awkwardly or bending your hands awkwardly can have an impact on the nerve and create the numb sensation.
Passionflower is common to use to treat insomnia, cramps, hysteria, and nerve pain and to aid asthmatics suffering from insomnia.
There are also other things that cause nerve damage, such as a head injury or tumor, side effects of some medications, or other medical problems.
The cars look incredible, making you wonder who would have the nerve to race them.
A disruption in the blood supply to the brain starves the brain of oxygen-rich blood and causes the nerve cells in that area to become damaged and die within minutes.
These piercings have been associated with infections, tooth fractures, periodontal disease, and nerve damage.
Gliomas are cancers of the nerve tissue.
Tumors along the optic nerve, causing vision disturbances in about 20 percent of those affected.
The characteristic symptoms of NF-2 are due to tumors along the acoustic nerve that result in nerve dysfunction and the loss of hearing.
Diagnosis of NF-2 requires the presence of either a nodule or mass (tumor) on the acoustic nerve or another distinctive nervous system tumor, which may only be identifiable through imaging studies.
Neurofibroma-A soft tumor usually located on a nerve.
Complications from forceps deliveries can occur, such as nerve damage or temporary bruises to the baby's face.
Depending on the type of medications used, this type of anesthesia can block nerve signals, causing temporary pain relief or a loss of sensation from the waist down.
The correct balance of electrolytes is crucial to many body functions, including muscle contraction and nerve impulse transmission.
There are two parts of the nerve that can be affected in CMT.
A nerve can be likened to an electrical wire, in which the wire part is the axon of the nerve and the insulation surrounding it is the myelin sheath.
Specialized testing of the nerves, called nerve conduction testing (NCV), can be performed to determine if CMT1 or CMT2 is present.
A nerve conduction velocity test should be performed to measure how fast impulses travel through the nerves.
Nerve conduction testing may be combined with electromyography (EMG), an electrical test of the muscles.
A nerve biopsy (removal of a small piece of the nerve) may be performed to look for changes characteristic of CMT.
Axon-A long, threadlike projection that is part of a neuron (nerve cell).
Nerve condition velocity (NCV)-Technique for studying nerve or muscle disorders, measuring the speed at which nerves transmit signals.
Interaction of histamine with receptors on blood vessel, nerve, and tissue cells causes inflammation and the accumulation of intracellular fluid released by the cells.
Fortunately, the nerve cells are not always completely destroyed.
By the end of a month, the nerve impulses start to return to the apparently paralyzed muscle and by the end of six months, recovery is almost complete.
If the nerve cells are completely destroyed; however, paralysis is permanent.
It is caused by the death of individual nerve terminals in the motor units that remain after the initial polio attack.
Paralysis-Loss of the ability to move one or more parts of the body voluntarily due to muscle or nerve damage.
Demyelination-Disruption or destruction of the myelin sheath, leaving a bare nerve.
It results in a slowing or stopping of the impulses that travel along that nerve.
The syndrome is due to inflammation and loss of the myelin covering of the nerve fibers, often associated with an acute infection.
Deep wounds to the hands and wrists should be examined for nerve and tendon damage.
Five well-designed studies failed to show a link between DTP vaccine and any chronic nerve conditions.
Most studies agree that symptoms of Tourette syndrome involve the chemicals in the brain that help transmit information from one nerve cell in the brain to another.
Neurotransmitter-A chemical messenger that transmits an impulse from one nerve cell to the next.
Spasticity occurs when certain nerve signals do not reach the muscles because of injury or disease that affects parts of the brain or spinal cord.
With spasticity, muscles receive improper nerve signals, causing them to contract, while the brain is unable to communicate with the motor nerves to stop the muscles from contracting.
Nerve conduction studies and an electromyogram (EMG) are usually performed together to provide a comprehensive assessment of nerve and muscle function.
In the nerve conduction study, small electrodes are placed on the skin over the muscles to be examined.
Selective dorsal rhizotomy surgery, also called selective posterior rhizotomy, involves a surgical resection of part of the spinal nerve.
By cutting the sensory nerve rootlets that cause the spasticity, muscle stiffness is decreased while other functions are maintained.
While an imbalance of certain neurotransmitters-the chemicals in the brain that transmit messages between nerve cells-is believed to be key to depression, external factors such as upbringing may be as important.
Motor neuron-A nerve cell that specifically controls and stimulates voluntary muscles.
Spinal cord-The elongated nerve bundles that lie in the spinal canal and from which the spinal nerves emerge.
Also nerve connections between the retina and brain are altered if melanin is not present in the retina during development.
They may have reduced depth perception due to altered nerve connections from the retina to the brain.
Specifically, acetylcholine, a chemical in the body that transmits nerve signals, is released from nerve endings and stimulates secretion of sweat.
Brachial plexopathy is any injury to the brachial plexus-the nerve bundles located on each side of the neck that give rise to the individual nerves controlling the muscles of the shoulders, arms, and hands.
The nerves of the brachial plexus are the fifth through the eighth cervical nerves (C5, C6, C7, and C8) and the first thoracic nerve (T1).
They run from nerve roots on each side of the upper spinal cord to regions beneath the collarbone where they branch out as the major nerves of the shoulders, arms, wrists, and hands.
Every brachial plexus injury is different, depending on the affected nerve or nerves and the extent and severity of the injury.
A stretch, praxis (damage), or traction (pulling or tension-creating) injury, in which the nerve has been overstretched and damaged but is not torn.
A rupture, in which there has been a separation within a nerve.
A single nerve may have more than one rupture.
A neuroma, in which scar tissue has formed around a nerve injury.
The scar tissue puts pressure on the nerve and interferes with nerve signal conduction to the muscles.
It is the detachment of a nerve from the spinal cord.
A minor brachial plexus injury can be a stretched nerve that results in a short-circuit in a few of the nerve fibers, causing temporary paralysis.
A more severe injury may involve a complete disruption of the nerve, in which the nerve fibers around the injury become disorganized, all nerve function is lost, and scarring prevents the nerve from healing.
Most injuries to the brachial plexus during birth involve the C5 and C6 nerve roots, affecting the movement of the shoulder, upper arm, and elbow.
Also called Erb/Klumpke palsy, total plexus palsy involves all of the nerve roots of the brachial plexus to at least some extent.
Breech deliveries increase the risk of brachial plexopathy by 175-fold, often causing bilateral injuries to the lower nerve roots of the brachial plexus.
Avulsion injuries require surgery to reattach the nerve root to the spinal cord.
In general, damage to the nerve sheath (outer covering) alone has a good prognosis.
Praxis-type injuries, in which the nerve is damaged but not torn, usually improve within three months and eventually heal completely.
Severed nerves, particularly avulsion injuries in which the nerve is severed at the root, have poorer prognoses.
In severe cases there may be permanent partial or total loss of nerve function in the affected nerves and weakness or paralysis of the arm may be permanent.
Klumpke's palsy or paralysis-A condition caused by an injury to the lower brachial plexus, involving the cervical nerves C7 and C8, and sometimes the thoracic nerve T1, causing weakness or paralysis in the hands and fingers.
Neurolysis-The destruction of nerve tissue or removal of scar tissue surrounding a nerve.
Neuroma-Scar tissue that forms around a nerve; a tumor derived from nerve tissue.
Much attention has focused on the connection between schizophrenia and neurotransmitters, the chemicals that transmit nerve impulses within the brain.
Nerve cells, or neurons, perform many functions in the body.
Nerve cell endings, or receptors, are responsible for pain sensation.
For example, some individuals who have suffered nerve damage as a result of viral infection experience unbearable pain from just the lightweight of their clothing.
Nociceptor-A nerve cell that is capable of sensing pain and transmitting a pain signal.
Cold sores are caused by the herpes simplex virus type 1 (HSV-1), which lives inside nerve tissue.
Once a child gets the virus, it stays in his body permanently, hiding in nerve cells near the ear.
It lives in nerve cells where the immune system cannot find it.
The nerve cells most affected by FA are those in the spinal cord involved in relaying information between muscles and the brain.
Laboratory tests include electromyography (a measurement of the electrical activity of muscle cells) and nerve conduction velocity tests, which measure the speed that nerves transmit impulses.
Diabetic neuropathy is the result of nerve damage caused by uncontrolled diabetes.
In peripheral neuropathy (PN), nerve damage in the extremities (e.g., the legs and feet) causes numbness, pain, and burning.
Damage to the nerve that leads from the ear to the brain can also cause vertigo.
An acoustic neuroma, for example, is a benign tumor that wraps around the nerve.
X rays, computed tomography scan (CT scan), and magnetic resonance imaging (MRI) can pinpoint evidence of nerve damage, tumor, or other structural problems.
Acoustic neuroma-A benign tumor that grows on the nerve leading from the inner ear to the brain.
Using large amounts of folic acid (e.g., over 5,000 mcg per day) can mask a vitamin B 12 deficiency and thereby risk of irreversible nerve damage.
One theory holds that a particular nerve pathway in the brain (dubbed the "mesolimbic reward pathway") holds certain chemical characteristics which can increase the likelihood that substance use will ultimately lead to substance addiction.
Some research suggests that impulse control disorders are linked to certain hormones, abnormal nerve impulses, and variations in brain chemistry and function.
For any mineral toxicity that causes nerve damage, the prognosis is often fair to poor.
Blood and urine biochemical tests, as well as genetic tests, may be used to rule out other possible causes, including muscle and peripheral nerve diseases, mitochondrial and metabolic diseases, and other inherited disorders.
Alcohol or phenol injections into the nerve controlling the muscle are another option.
A neurosurgeon performing dorsal rhizotomy carefully cuts selected nerve roots in the spinal cord to prevent them from stimulating the spastic muscles.
Dorsal rhizotomy-A surgical procedure that cuts nerve roots to reduce spasticity in affected muscles.
Furthermore, the bowel and bladder have inadequate nerve connections, causing an inability to control bowel and bladder function.
Both closed and penetrating head injuries can cause swirling movements throughout the brain, tearing nerve fibers and causing widespread bleeding or a blood clot in or around the brain.
Numbness and tingling are decreased or abnormal sensations caused by altered sensory nerve function.
Sensation is carried to the brain by neurons (nerve cells) running from the outer parts of the body to the spinal cord in bundles called nerves.
This disturbance can occur in the central nervous system (the brain and spinal cord), the nerve roots that are attached to the spinal cord, or the peripheral nervous system (nerves outside the brain and spinal cord).
Direct compression of the nerve also causes paresthesias.
Chronic nerve compression occurs in entrapment syndromes.
The most common example is carpal tunnel syndrome, which occurs when the median nerve is compressed as it passes through a narrow channel in the wrist.
Repetitive motion or prolonged vibration can cause the lining of the channel to swell and press on the nerve.
Chronic nerve root compression, or radiculopathy, can occur in disk disease or spinal arthritis.
For instance, the median nerve innervates the thumb, the first two fingers, half of the ring finger, and the part of the hand to which they connect.
The ulnar nerve innervates the other half of the ring finger, the little finger, and the remainder of the hand.
Other symptoms may accompany paresthesias, depending on the type and severity of the nerve disturbance.
Nerve conduction velocity tests, electromyography, and imaging studies of the affected area may be employed.
Nerve biopsy may be indicated in selected cases.
In the early 2000s trials are being done to determine whether treatment with human nerve growth factor will be effective in regenerating the damaged nerves.
Motor nerve-Motor or efferent nerve cells carry impulses from the brain to muscle or organ tissue.
Karaca, P., et al. "Painful paresthesiae are infrequent during brachial plexus localization using low-current peripheral nerve stimulation."
Lastly, the doctor examines the child's eyes to make sure that the pupils are responding normally to light and that the child is not seeing double or having other visual problems that might indicate nerve damage or damage to the eye itself.
One part of the brain that was as of 2004 being studied is the amygdala, an almond-shaped body of nerve cells involved in normal fear conditioning.
Neuroimaging-The use of x-ray studies and magnetic resonance imaging (MRI) to detect abnormalities or trace pathways of nerve activity in the central nervous system.
Gangliosides are fatty substances necessary for the proper development of the brain and nerve cells (nervous system).
They build up within the brain, interfering with nerve functioning.
Ganglioside-A fatty (lipid) substance found within the brain and nerve cells.
The nerve damage associated with ADP could cause breathing impairment or lead to weakness or paralysis of the arms and legs.
A physical examination requires careful scrutiny of the wound, with special attention to possible bone, joint, ligament, muscle, tendon, nerve, or blood-vessel damage caused by deep punctures or severe crush injuries.
Excessive pressure over a nerve can cause irritation or possible damage if not corrected.
The retina transforms the image it receives into electrical signals that are sent to the brain via the optic nerve.
Herpes zoster virus-Acute inflammatory virus that attacks the nerve cells on the root of each spinal nerve with skin eruptions along a sensory nerve ending.
Occasionally, magnetic resonance imaging (MRI) is used as a diagnostic tool, primarily to look more closely at the condition of the spinal cord and nerve roots extending from it if neurological problems are suspected.
Symptoms that have a waning course with recurrences and worsen over time suggest a disease that destroys nerve cells.
Depressed reflexes in only one limb, while the other limb demonstrates a normal response usually indicates a peripheral nerve lesion.
Corticospinal tract-A tract of nerve cells that carries motor commands from the brain to the spinal cord.
The nerve cells, or neurons, in this part of the hypothalamus secrete substances known as hypocretins or orexins, which regulate the sleep/wake cycle in humans.
Myopathies are diseases of skeletal muscle that are not caused by nerve disorders.
In a pallid BHS the brain sends a signal via the vagus nerve that severely slows the heart rate, leading to a temporary cessation of breathing and loss of consciousness.