Peripheral transmission

Visual evoked potentials (VEPs) and brainstem auditoiy evoked potentials (BAEPs) measure speed of conduction in the nerves that ran from the eyes and ears, respectively, to the relevant locations in the brain. On stimulation, nerves send signals in the form of waves that can be detected, and the time it takes for an impulse to initiate an evoked potential is latency. The VEP is the first positive wave and usually occurs at 100 ms (PlOO latency) after the visual stimulus. That measure is very sensitive to demyelination of the optic nerve. BAEPs also have discrete waveforms. Wave I arises from the auditory nerve, and its latency reflects peripheral transmission time wave 111 is generated predominantly from the auditoiy pathway in the lower brainstem and wave V is generated from the upper brainstem. The use of interpeak latencies helps distinguish changes in peripheral auditory nerve latency from changes in brainstem transmission in the auditoiy pathway. 

The various parts of a computer have different functions to deal with peripherals (the viewing screen, the mouse, the keyboard, and inputs and outputs for transmission of data), and all of these... 

Asbestos fiber identification can also be achieved through transmission or scanning electron microscopy (tern, sem) techniques which are especially usefiil with very short fibers, or with extremely small samples (see Microscopy). With appropriate peripheral instmmentation, these techniques can yield the elemental composition of the fibers using energy dispersive x-ray fluorescence, or the crystal stmcture from electron diffraction, selected area electron diffraction (saed). 

Peripheral sympathetic blocking agent. A drug that disrupts the transmission of nerve impulses to sympathetically innervated structures. 

Systems may also include modems, which connect small computers or terminals to other computers or workstations either in-house or over telephone system lines and whose speed of transmission is rated by baud (for binary information units, the number of bits transmitted per second). Common baud rates for small systems are 2400 or 9600 with higher rates possible. Computers may also be networked together to share data or peripheral components such as highspeed printers. 

Fig. 9,20 Spiral bevel ring gear assembly from the forward transmission gear box of Boeing Vertol 234-LR (Chinook) aircraft registration G-BWFC which crashed into the sea off the Shetland Isles in 1986. Note the peripheral and radial fractures in the gear, which appeared to be responsible for the crash. There was evidence of fretting and galvanic corrosion which may have been responsible for initiation of the fracture sequence...

Analgesics interfere with the generation and/or transmission of impulses following noxious stimulation ( nociception) in the nervous system. This can occur at peripheral and/or central levels of the neuraxis. The therapeutic aim is to diminish the perception of pain. 

Cholinergic Transmission is the process of synaptic transmission which uses mainly acetylcholine as a transmitter. Cholinergic transmission is found widely in the peripheral and central nervous system, where acetylcholine acts on nicotinic and muscarinic receptors. 

Sensory nerves are peripheral nerves involved in the detection of exogenous and endogenous stimuli for transmission into the CNS. They can be subdivided into RARs and C-fibres according to their channel characteristics. 

Systemic and coronary arteries are influenced by movement of calcium across cell membranes of vascular smooth muscle. The contractions of cardiac and vascular smooth muscle depend on movement of extracellular calcium ions into these walls through specific ion channels. Calcium channel blockers, such as amlodipine (Norvasc), diltiazem (Cardizem), nicardipine (Cardene), nifedipine (Procardia), and verapamil (Calan), inhibit die movement of calcium ions across cell membranes. This results in less calcium available for the transmission of nerve impulses (Fig. 41-1). This drug action of the calcium channel blockers (also known as slow channel blockers) has several effects on die heart, including an effect on die smooth muscle of arteries and arterioles. These drug dilate coronary arteries and arterioles, which in turn deliver more oxygen to cardiac muscle. Dilation of peripheral arteries reduces die workload of die heart. The end effect of these drug is the same as that of die nitrates. 

To our knowledge no smdies have examined the effects of nitrites on GABA neuro transmission. However, when NO, the major mediator of the peripheral effects of nitrites, was administered within the paraventricular nucleus, it caused an increase in GABA concentrations (Horn et al. 1994). 

Neurohumoral transmitters are chemicals that facilitate the transmission of nerve impulses across nerve synapses and neuroeffector junctions. Acetylcholine is a neurohumoral transmitter that is present in the peripheral autonomic nervous system, in the somatic motor nervous system, and in some portions of the central nervous system. 

Byrn RA, Kiesshng AA (1998) Analysis of human immunodeficiency virus in semen indications of a genetically distinct virus reservoir. J Reprod Immunol 41(1-2) 161-176 Carr JM, Hocking H, Li P, Burrell CJ (1999) Rapid and efficient celL-to-ceU transmission of human immunodeficiency vims infection from monocyte-derived macrophages to peripheral blood lymphocytes. Virology 265(2) 319-329... 

It was generally assumed that it cannot and this became known as Dale s Law. During his studies on antidromic vasodilation he wrote (1935) When we are dealing with two different endings of the same sensory neuron, the one peripheral and concerned with vasodilation and the other at a central synapse, can we suppose that the discovery and identification of a chemical transmitter at axon reflex dilation would furnish a hint as to the nature of the transmission process at a central synapse. The possibility has at least some value as a stimulus to further experiments . 

BZ is usually disseminated as an aerosol with the primary route of entry into the body through the respiratory system the secondary route is through the digestive tract. BZ blocks the action of acetylcholine in both the peripheral and central nervous systems. As such, it lessens the degree and extent of the transmission of impulses from one nerve fiber to another through their connecting synaptic junctions. It stimulates the action of noradrenaline (norepinephrine) in the brain, much as do amphetamines and cocaine. Thus, it may induce vivid hallucinations as it sedates the victim. Toxic delirium is very common. 

Figure 1.1 Functional components of the nervous system. The sensory division of the peripheral nervous system is sensitive to changes in the internal and external environment. The information gathered by this component is transmitted to the CNS where it is processed, integrated, and interpreted. The CNS then determines the appropriate response to this input. This response is carried out by the transmission of nerve impulses in the motor division of the peripheral nervous system to the effector tissues.

Nonnarcotic analgesics. The nonnarcotic analgesics include aspirin, NSAIDs, and acetaminophen. Aspirin acts centrally and peripherally to block the transmission of pain impulses. Furthermore, it reduces fever and inflammation and inhibits synthesis of the prostaglandins that increase the sensitivity of nociceptors. 

Complexation of gold ions, [Au(I)], with peripheral phosphine groups of a P-based dendrimer was reported by Majoral et al. [185]. Transmission electron microscopy (TEM) was used to analyze the large aggregates formed by the dendritic gold complexes and a direct correlation was observed between the size of the particles and the dendrimer generation number. In a recent report [186], Majoral et al. further demonstrated that up to 48 diphosphino groups could be anchored to the surface of dendrimers and various dendritic metal-complexes... 

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