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1938: Television - Archive Article - MSN Encarta At a distant point these electrical impulses are taken by a receiver and retransformed into a faithful reproduction of the original images and scenes, and made visible to an observer. These electrical impulses, into which light from the various areas of the illuminated object has been transformed, may now be sent into a radio amplifier and these stepped-up electrical impulses transmitted by wire or by radio as are other radio signals. Hence, if the varying electrical impulses which have been transmitted by wire or by radio from the transmitting set are applied to the neon tube, its illumination will fluctuate in just the same way as did the light falling originally on the transmitter. encarta.msn.com /sidebar_461500847/1938_Television.html   (1078 words)

Nikola Tesla's "Means for Increasing the Intensity of Electrical Oscillations" In many scientific and practical uses of electrical impulses or oscillations—as, for example, in systems of transmitting intelligence to distant points—it is of great importance to intensify as much as possible the current impulses or vibrations which are produced in the circuits of the transmitting and receiving instruments, particularly of the latter. It is well known that when electrical impulses are impressed upon a circuit adapted to oscillate freely the intensity of the oscillations developed in the same is dependent on the magnitude of its physical constants and the relation of the periods of the impressed and of the free oscillations. In an apparatus for transmitting or receiving electrical impulses or oscillations, the combination with a primary and a secondary circuit, adapted to vibrate freely in response to the impressed oscillations, of means for artificially cooling the same to a low temperature, as herein set forth. www.tfcbooks.com /patents/super_c.htm   (1128 words)

Management of Arrhythmias (Abnormal Heartbeats) The impulse then reaches the atrioventricular (AV) node, which acts as an electrical bridge allowing impulses to travel from the atria to the ventricles. Electrical cardioversion -- in patients with persistent arrhythmias (such as atrial fibrillation), a normal rhythm may not be achieved with drug therapy alone. After administration of a short-acting anesthesia, an electrical shock is delivered to your chest wall that synchronizes the heart and allows the normal rhythm to restart. www.clevelandclinic.org /health/health-info/docs/1800/1835.asp?index=8245   (2506 words)

Electrical Impulses Foster Insulation of Brain Cells, Speeding Communications, March 17, 2006 News Release - National ... Electrical impulses foster myelination, the insulation process that speeds communication among brain cells, report researchers at two institutes of the National Institutes of Health. A neuron generates an electrical impulse, causing the cell to release its neurotransmitters, he said. This electrical stimulation was designed to mimic the normal activity that takes place in the brain when neurons communicate with each other. www.nih.gov /news/pr/mar2006/nichd-17.htm   (765 words)

UpToDate Patient information: Pacemakers The electrical signals, or impulses, of the heart are generated by specialized tissue called the sinoatrial (SA) or sinus node (show figure 1). The electrical impulse then spreads to the atrioventricular (AV) node, which is another area of specialized tissue located between the atria and the ventricles. Problems with the flow of electrical impulses in the heart are called arrhythmias, which is a general term meaning a deviation from the normal pattern of electrical conduction or electrical rhythm. patients.uptodate.com /topic.asp?file=hrt_dis/9666   (3955 words)

[No title] At the AV node, the impulses are regulated, slowed down and sorted out to make sure that the correct number of impulses reach their destination. The P wave is associated with electrical activity in the atria, and the other waves reflect electrical activity in the ventricles. The EKG is used to trace the electrical pulses on their journey through the heart and gives an excellent indication of how well the conductive system is functioning, as well as detecting any underlying problems. heart.health.ivillage.com /arrhythmia/conductionsystem2.cfm   (449 words)

Nerve Impulses These impulses are due to events in the cell membrane, so to understand the nerve impulse we need to revise some properties of cell membranes. In nerve and muscle cells the membranes are electrically excitable, which means they can change their membrane potential, and this is the basis of the nerve impulse. The frequency of the impulse is related to the intensity of the stimulus. www.biologymad.com /NervousSystem/nerveimpulses.htm   (2352 words)

Sarasota Memorial Health Care System - Arrhythmias The initial electrical impulses are generated within a special group of cells located in the heart’s right atrium (the right upper chamber). The impulses from the SA node travel from the atria (the two upper chambers of the heart) to the AV node (atrioventricular node). The AV node serves as a relay station to conduct the impulses from the atria to the ventricles. www.smh.com /sections/hv_institute/disease-heart/disease_arrhythmias.html   (2066 words)

dreddyclinic.com - Heart arrhythmias (arrhythmias) Exiting the AV node, the impulse is conducted along two electrical pathways (right and left bundles), which spread impulses throughout the right and left ventricles. In addition, the inability of heart cells to conduct electrical impulses during the refractory period acts as a buffer, preventing the occasional offbeat electrical impulse from developing into an arrhythmia. This pathway may allow electrical current to pass between the atria and the ventricles without passing through the AV node, leading to short circuits and rapid heartbeats. www.dreddyclinic.com /findinformation/hh/heartarrhythmias.htm   (3069 words)

Heart Rhythm Disorders The electrical system regulating heartbeat consists of 2 main areas of control and a series of conducting pathways, similar to the electrical wiring in a house (See Multimedia File 1). Electrical impulses leave the SA node and travel through special conducting pathways in the heart to the other controller, the atrioventricular, or AV, node. Atrial fibrillation: A common condition caused by electrical impulses discharged at a rapid rate from many different areas of the atria. www.emedicinehealth.com /heart_rhythm_disorders/article_em.htm   (812 words)

Genetic 'missing link' sheds light on sudden cardiac death An electrical imbalance caused by a malfunctioning gene triggers a potentially fatal heart rhythm disorder, according to researchers at Baylor College of Medicine (BCM) and Texas Children's Hospital in Houston. Electrical impulses originate in the top of the heart's right atrium and travel through the muscle fibers, causing the heart to contract. Electrical abnormality in the heart is the leading cause of sudden cardiac death in the absence of muscle disease. www.eurekalert.org /pub_releases/2006-11/bcom-gl110606.php   (445 words)

Heart Block In this condition, the electrical signals that stimulate heart muscle contractions are partially or totally blocked between the upper chambers (atria) and the lower chambers (ventricles). The electrical impulses are slowed as they pass through the conduction system, but all of them successfully reach the ventricles. The electrical signal travels down the bundle branches to thin fibers that distribute the electrical impulse to the muscles of the ventricles, the major pumping chambers of the heart. www.hrspatients.org /patients/heart_disorders/heart_block.asp   (786 words)

Guide to arrhythmias Your heart's electrical impulses are translated into a wavy line on a strip of moving paper, enabling doctors to determine the pattern of electrical current flow in the heart, diagnose arrhythmias and heart damage. These catheters sense electrical impulses and may also be used to stimulate different areas of the heart. Normally, except at the AV node, the atrium is electrically insulated from the ventricle by fibrous tissue. www.angelfire.com /ab/cardiosv/arrhythmia.html   (668 words)

Pacemakers  - Texas Heart Institute Heart Information Center Electrical impulses from the heart muscle cause your heart to beat (contract). When an electrical impulse is released from this natural pacemaker, it causes the upper chambers of the heart (the atria) to contract. The SA node sends electrical impulses at a certain rate, but your heart rate may still change depending on physical demands, stress, or hormonal factors. www.texasheart.org /HIC/Topics/Proced/pacemake.cfm   (945 words)

Multifocal atrial tachycardia Multifocal atrial tachycardia describes a rapid heart rate caused by inappropriate electrical impulses arriving at the lower heart chambers (ventricles) from multiple locations within the upper heart chambers (atria). Normally, electrical impulses in the heart begin in the right atrium, in an area called the sinoatrial node (sinus node or SA node), which is the natural "pacemaker" of the heart. The electrical impulses are conducted throughout the heart, and the heart responds to each impulse with a contraction. www.pennhealth.com /ency/article/000186.htm   (617 words)

Electrical Injuries: Engineering, Medical and Legal Aspects Electric currents and electromagnetic radiation, both ionizing and nonionizing, can produce harmful biological effects in humans; these effects are the subject of an ever growing number of lawsuits. Part II covers the medical aspects of electrical injuries, including the consequences of electrical injury on the body, EKGs and pacemakers, accident reconstruction in electrical injury cases, common sources of electrical injury and relevant medical literature. This section also explains how electrical impulses control and influence muscle cells throughout the body as well as the pumping of blood throughout the heart. www.medleague.com /webstore/lawyersandjudges/electricaleml.htm   (230 words)

riversideonline.com - Bundle branch block Even though interference with the impulses may happen for only a fraction of a second, that may be enough to cause bundle branch block. As part of this route from the AV node to the ventricles, the impulses move along a slender cluster of cardiac fibers called the "bundle of His" (named after a German physician, Wilhelm His), which divides into two branches — the right and the left bundles — one for each of the heart's ventricles. Electrical impulses that cause your heart to beat (contract) originate in the upper right chamber (right atrium) of the heart and travel to the lower chambers (ventricles). www.riverside-online.com /health_reference/Disease-Conditions/DS00693.cfm   (1429 words)

UPHS News: Controlling Your (Nerve) Impulses   (Site not responding. Last check: 2007-09-10) Electrical impulses in neurons are created when these ions are allowed to return to their original locations by passing rapidly through channels in nerve cells’ outer membranes. The efficient and speedy passage of nerve impulses along axons is aided by the presence of an insulating cover, known as myelin, which maintains the electrical activity along the entire length of the axon. The nerve impulse is able to skip across the unmyelinated regions of the axon at the nodes of Ranvier, with the help of sodium and potassium channels. www.uphs.upenn.edu /news/News_Releases/mar06/ionchnl.htm   (1027 words)

Heart Rhythm Disorders: Supraventricular Tachycardia Once this occurs, the electrical impulses are released and travel down special fibers to surround the sides and floor of the ventricles. Electrical leads are attached to cloth patches and placed on the arms and legs and across the chest. Electrical cardioversion is often used for distressing symptoms of atrial flutter or atrial fibrillation. www.pdrhealth.com /patient_education/BHG01CA03.shtml   (2835 words)

Glossary of Terms (N) Neurostimulation (including spinal cord stimulation and peripheral nerve stimulation) uses a small neurostimulation system that is surgically placed under the skin to send mild electrical impulses to the spinal cord or a specific nerve(s) that's causing pain. The electrical impulses are delivered through a lead (a special medical wire) that is also surgically placed. Both of these systems are surgerical placed under the skin to send mild electrical impulses to the spinal cord or to the specific nerve that is causing pain. www.medtronic.com /corporate/glossary/n.html   (156 words)

MDA / Quest 6-3 / The Heart is A Muscle, Too A It may sound funny to talk about the electrical properties of the heart, but electricity is a form of energy that results from the flow of charged particles, whether they're in a biological or manufactured system. These "wiring" cells control the rate and rhythm of the heartbeat by controlling the rate and direction of electrical impulses as they go through the heart (see illustration). Here, impulses are delayed for about a 10th of a second, just long enough to allow the atria to contract and add blood to the heart's lower chambers -- the ventricles -- before the ventricles get the signal to contract. www.mda.org /publications/Quest/q63cardiac.html   (2274 words)

Electromyogram (EMG) and Nerve Conduction Studies Measuring the electrical activity in muscles and nerves can help detect the presence, location, and extent of diseases that can damage muscle tissue (such as muscular dystrophy) or nerves (such as amyotrophic lateral sclerosis). The electrical activity in the muscle is displayed as wavy and spiky lines on a special video monitor (oscilloscope) and may also be heard on a loudspeaker as machine gun-like popping sounds when you contract the muscle. Repeated, brief electrical pulses are administered to the nerve, and the time it takes for the muscle to contract in response to the electrical pulse is recorded. www.webmd.com /hw/chicken_pox   (1740 words)

System of Transmission of Electrical Energy The distance extends with the increase of the electromotive force of the impulses, with the diminution of the density of the atmosphere, with the elevation of the active terminal above the ground, and also, apparently, in slight measure, with the degree of moisture contained in the air. I have likewise observed that this region of decidedly-noticeable influence continuously enlarges as time goes on, and the discharge is allowed to pass not unlike a conflagration which slowly spreads, this being possibly due to the gradual electrification or ionization of the air or to the formation of less insulating gaseous compounds. The method hereinbefore described of transmitting electrical energy through the natural media, which consists in producing at a generating-station a very high electrical pressure, causing thereby a propagation or flow of electrical energy; by conduction, through the earth and the air strata, and collecting or receiving at a. www.tfcbooks.com /patents/system.htm   (539 words)

Brain & Nervous System > Electrical Impulses Foster Insulation of Brain Cells, Speeding Communications Electrical Impulses Foster Insulation of Brain Cells, Speeding Communications The study appears in the March 16 Neuron and was conducted by researchers at the National Institute of Child Health and Human Development and the National Cancer Institute. Neurons - specialized cells of the brain and nervous system - communicate via a relay system of electrical impulses and specialized molecules called neurotransmitters, explained the study's senior author, R. Douglas Fields, Ph.D., Head of NICHD's Nervous System Development and Plasticity Section. www.emaxhealth.com /85/5017.html   (623 words)

About Arrhythmia In patients with heart block, the impulse originating in the sinus node is either delayed or completely interrupted during its journey to the ventricles through the AV node. Atrioventricular (AV) block: An electrical impulse from the atria is either delayed or blocked on its way to the ventricles. Ventricular fibrillation: Electrical impulses from multiple sites in the ventricles are fired in a very fast and uncontrolled manner, causing the heart to quiver rather than to beat and pump blood. www.med.nyu.edu /heartrhythm/patients/about_arrhythmia.html   (1106 words)

Sports Medicine Advisor 2005.4: Electrical Nerve Stimulation Electrical stimulation is also known as transcutaneous electrical nerve stimulation (TENS). Electrical stimulation is often used to reduce pain and sometimes used to promote healing in an injured or diseased part of the body by stimulating the muscles. Low voltage electrical impulses are delivered to surface nerves in the skin. www.med.umich.edu /1libr/sma/sma_ens_sma.htm   (472 words)

Pacemaker placement - Quest Diagnostics Patient Health Library   (Site not responding. Last check: 2007-09-10) A pacemaker is a small, battery-powered device that sends out weak electrical impulses that cause the heart muscle to contract. A pacemaker consists of wires (leads), which transmit electricity to the heart, and the pulse generator and battery, which generate the electrical impulses. Pacemakers can be surgically placed into the chest (a permanent pacemaker) through a small incision, or they can be worn outside the body (a temporary pacemaker) and attached to the heart through a wire that is threaded through a neck vein. www.questdiagnostics.com /kbase/topic/detail/surgical/aa108101/detail.htm   (1164 words)

Fat may affect electrical impulses in brain, heart April 14, 2005 -- Fatty molecules may modulate the electrical characteristics of nerve and heart cells by regulating the properties of key cell pores, according to research conducted at Washington University School of Medicine in St. Louis. The researchers report in the April 26 issue of the Proceedings of the National Academy of Sciences that the proteins in specific electrically responsive cell pores--voltage-sensing potassium channels--can bind to molecules of palmitate. Their protein units form pores that permeate the outer wall or membrane of the cell and selectively allow the passage of potassium ions, which are essential components of cell signaling systems. www.eurekalert.org /pub_releases/2005-04/wuso-fma041405.php   (681 words)

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