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Biology 202, Spring 2005
Third Web Papers
Electricity: Good or Bad?
Sophia LouisIs electricity a harmful force to our bodies? Our brains send electricity down nerve cells towards muscles for example, to release neurotransmitters, but how does exposure to external electricity affect the nervous system? It is evident that large doses of electrical input are harmful to the body, what are the effects of smaller doses of electricity? Three sources of external electricity that can be inflicted upon the body include lightning, electro convulsive therapy (ECT), and stun guns. Injuries caused by lightning tend to affect any or all parts of the nervous system, specifically the central nervous system (CNS) and the autonomic nervous system, which is a subdivision of the peripheral nervous system (PNS) (7). The peripheral nervous system consists of sensory neurons running from stimulus receptors that inform the central nervous system of the stimuli, and of the motor neurons that run from the central nervous system to the muscles and glands-called effectors- that take action. The peripheral nervous system is subdivided into the sensory-somatic nervous system and the autonomic nervous system. Lightning injuries tend to affect the autonomic nervous system.
The central nervous system (which includes the brain and spinal cord) is made up of two basic types of cells: neurons and glia. Glial cells are the support cells of neurons. They outnumber neurons by a substantial amount (some scientists have estimated it to be as large as nine to one) but in spite of their smaller numbers, neurons are the key players in the brain (3). Everything we think, feel and do would be impossible without the work of neurons and their support cells. Neurons are information messengers. They use electrical impulses and chemical signals to transmit information between different areas of the brain, and between the brain and the rest of the nervous system. Neurons have three basic parts: a cell body and two extensions called axons and fingerlike dendrites. Within the cell body is a nucleus, which controls the cell's activities and contains the cell's genetic material, the axon looks like a long tail and transmits messages from the cell, and dendrites look like the branches of a tree and receive messages for the cell. Neurons communicate with each other by sending chemicals, called neurotransmitters, across a tiny space, called a synapse, between the axons and dendrites of adjacent neurons.
When a neuron is stimulated -- by heat, cold, touch, sound vibrations or some other message -- it begins to actually generate a tiny electrical pulse. This electricity and chemical change travels through the axon, and the full length of the neuron. But when it gets to the end of finger-like projections (dendrites) at the end of the neuron, it needs help getting across to the next extended finger. That's where chemicals come in. The electrical pulse in the cells triggers the release of chemicals that help carry the pulse to the next cell. This process consistently repeats itself, unless interrupted (3).
Serious lightning injuries affect about 1,000 to 1,500 people each year. Approximately 100 to 600 of them die, producing a 25 to 32% mortality rate. Of the survivors, 74% sustain permanent injuries. These statistics prove that there are more deaths caused by lightning than any other natural phenomena including floods, hurricanes and tornadoes. The current in a lightning bolt is as high as 30,000 Amperes with 1,000,000 or more Volts and lasts a short duration of about 1-100 milliseconds limits. Lightning strikes in several ways. The most severe is a direct strike either on the victim or on some object that he or she is holding i.e. a golf club, tripod, or umbrella. A "side flash" occurs when lightning hits a nearby object and jumps to the victim. Ground currents strike the victim when lightning strikes the ground nearby and it spreads to the person (7).
Injuries to the CNS as a result of lightning are common (7). Transient confusion, paralysis and amnesia are likely. Coagulation of the brain, collections of blood surrounding the brain, and bleeding within the brain are possible with direct strikes. Swelling of the brain is another outcome. Paresthesias (pins and needles sensations) may affect areas of the victim's body. Amnesia, movement disorders, dementia and decreased reflexes may occur. Paraplegia can be secondary to brain or spinal cord injury from lightning strikes. There may also be neuropsychiatric complications such as depression, anxiety, memory deficits, and post-traumatic stress disorder. When the brain is affected, the person often has difficulty with short-term memory, coding new information and accessing old information, multitasking, distractibility, irritability and personality change. This outside source of electricity forced onto the body interrupts and tampers with all of the electrical signals being sent in the body. The electricity forced into the body confuses the brain and forces the victim to respond to too many signals simultaneously (8).
Victims of lightning attacks may appear slow because it takes longer for information to be processed. They become easily distracted because they cannot monitor irrelevant stimuli at the same time as they are attending to the relevant stimulus. They seem to lose some of their memory because while they are focusing on point A, they do not have the processing space to think about point B simultaneously. These victims basically seem inattentive because when the amount of information they are given exceeds their mental capacitates, they cannot take it all in. Throughout the semester, we have used the example of the brain being similar to a computer. To use this analogy again: if an electric shock were sent through a computer, the outside would probably look un harmed(similar to a photo or x-rays of the person), the computer boards on the inside would probably look fine also and not be fused or melted (like a Cat scan or MRI for the person), but when you boot up the computer it would have difficulty accessing files, making calculations, printing, etc. similar to a person with brain injury who has short term memory problems, difficulty accessing and coding information, and difficulty organizing output. Victims of lightning strikes usually enter a state of depression resulting from frustration. They become frustrated with their limited capabilities, inability to function with ease and comfort both physically and mentally (8).
Electro convulsive Therapy (ECT) has been used for over 60 years as treatment for mental health disorders, most commonly, depression (6). ECT is useful for patients with significant depression, particularly for those who cannot take or are not responsive to antidepressants, who have severe depression, and/or those who are at high risk for suicide. Research shows that ECT has been most effective in cases where antidepressant medications do not provide sufficient relief of symptoms. ECT relieves depression within 1 to 2 weeks after beginning treatments. Electro convulsive therapy involves delivering elective shocks to the brain. This current is used to provoke spasms or convulsions/seizures and has a beneficial impact on depression patients. The seizures that occur as a result of the shock leads to a massive neuro-chemical release in the brain. Scientists still do not know exactly why ECT works -- except that it has less to do with electrical jolts than with the seizure they induce (1). Electricity runs through our brains already; that is what causes the neurons to fire and discharge neurotransmitters, which then carry the impulse across the synapse to the next cell. "Brain cells are set up in oscillating circuits that are firing regularly, what you are trying to do when you induce a seizure is get them all to fire in synchrony" (2). Many psychiatrists believe an ECT seizure increases the brain's sensitivity to the neurotransmitter serotonin, which is necessary because people deficient in serotonin are more prone to depression. Researchers believe that ECT raises the brain's seizure threshold, causing an anti-convulsive effect that may also involve increased serotonin levels (1).
As you can see, the mentioned sources of external electricity have served to be both good and bad. The source of external electricity that is most interesting is found in a stun gun. Stun guns do not emit natural electricity, nor are they used for medical procedures. Stun guns are used for protection against attackers. They are actually considered Bio-effect weapons, which cause electro muscular disruption (EMD).
There are three types of stun guns/stunning devices available on the market: Static Charge which uses an electrical watt with static to disrupt localized muscle groups, Phase-Induction which uses an electrical watt with phase induction to better facilitate the delivery of a static charge, and a T Wave which uses an electrical watt with electro-muscular disruption (EMD) technology. An electro-muscular disruption signal affects the central nervous system and all of its signals to the body (4).
The most powerful stun guns are the T-Wave guns, which contain air tasers. These are most efficient in causing electro-muscular disruption. T-Wave stun guns use 18-26 electrical watts, which completely override the central nervous system and directly take control over the skeletal muscles. This external electrical power causes an uncontrollable contraction of the muscle tissue, allowing the Taser to physically debilitate a target regardless of pain tolerance or mental focus. These stun guns are specifically classified as EMD weapons-designed to stop even the most aggressive attacker. This gun does not only interfere with communication between the brain and muscles, the Taser EMD systems directly tell the muscles what to do, in almost all cases, the target's muscles contract so much that they are forced to fall to the ground. The Taser has not been proven to cause any permanent damage or long-term after effects to muscles, nerves or other body functions. The basic idea of a stun gun is to disrupt the communication system. They have a charge with a lot of pressure but not much intensity. Since the voltage is high, the charge will pass through the body rapidly, but only at about 3 milliamps. This is not intense enough to damage the attacker's body. I do contend that if these stun guns are used recklessly, permanent damage may be done i.e. if it is applied for an extended period of time. A January 1987 Annals of Emergency Medicine study reported TASER technology leaves no long term injuries compared with 50% long term injuries for gun shot injuries, but are successful in causing EMD. Electro-muscular disruption occurs when the central nervous system is completely overridden. The device (Taser) overrides the CNS and takes control over the skeletal muscles.
Stun guns key into the nervous system and interrupt the many electrical signals from the CNS. The external electricity interrupts the neurological impulses that travel through the body to control and direct voluntary movement (5). When an attacker's neuromuscular system is overwhelmed by the stun gun, disorientation and loss of balance occurs instantly. Each of the aforementioned devices emits various charges. Static charge devices emit charges from 80,000 Volts-500, 000 Volt at 5-20 electrical watts (4). This charge is strong enough to take down any attacker, but if used correctly it is not lethal. When the Static Charge device is used, the attacker receives the shock of his or her life. They are immediately forced to stop, and are left feeling dazed for up to 15 minutes and suffer from muscle spasms. This is all a result of a brief shock of 1-2 seconds. Research shows that a "5 second shock can leave an attacker feeling as if he or she fell out of a two-story building and landed on a concrete sidewalk".
Merely touching someone with a stun gun immobilizes them for several minutes. What happens to the electrical signals that are being sent to the attacker's muscles? The energy stored in the stun gun is emitted into the attacker's muscles at a pulse frequency that is essentially too much to handle. This outside energy forces the muscle to do a great deal of work too rapidly, thus causing a state of muscular confusion. This is known as the rapid-work cycle that instantly depletes the attacker's blood sugar by converting it to lactic acid. The attacker loses all the energy in his muscles and his body is no longer able to function properly. Stun guns are designed to hamper with ones nervous system. The person becomes temporarily disabled and re-equilibrium of the nervous system takes some time.
Electricity is one of the most essential elements in your body. It is necessary to do just about everything. We tend to think of electricity as a harmful force to our bodies. If lightning strikes you, or your blow-dryer falls into your bath, or you stick your finger in an electrical outlet, the current can permanently harm or even kill you. The notion that "everything should be done in moderation" holds true even in neuroscience. In large doses, electricity is potentially harmful but in smaller doses electricity may be harmless.
1) Electroconvulsive therapy: Treatment for depression. Mayo Foundation for Medical Education and Research (MFMER). downloaded 4-14-2004
2) Barklage, N. and Jefferson, J.W. Electroconvulsive Therapy – A Guide. 2002. Madison Institute of Medicine, Inc., Madison, WI 53717
3) Schwartz, James., Jessell, Thomas. 1996. "Essentials of Neural Science and Behavior".McGraw-Hill.USA
5)Spray or Stun Information
6)History of Electroconvulsive Therapy
7)Brain and Nerve Injury
8)Lightning Safety Awareness
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