Neurons; semi-permeable membrane

Neurons; semi-permeable membrane Neurons are covered by a semi-permeable membrane that contains Ion Channels. These ion channels open and close to let positive ions, such as sodium (Na+) and potassium (K+), and negative ions, like chlorine (Cl-), enter the neuron. Ion channels are closed when the neuron is not transmitting information or is resting. Using a device called the oscilloscope, neuroscientists have found that the Resting Potential of a neuron (or the electrical charge of a resting neuron) is -70 millivolts (mV). Thus, an electric eel having 8,400 neurons can generate up to 588 V! Because a resting neuron is negatively charged in relation to its positive surrounding (that is, more negative ions are present inside the cell body of the neuron), a resting neuron is said to be polarized. However, when dendrites receive neurotransmitters from neighboring neurons, the ion channels open up and let positive ions depolarize the neuron. The Action Potential of a neuron (or the electrical charge of an activated neuron) depends upon the kind of neurotransmitter housed by the neuron. The qualitative differences between neurons result to variation in their voltage threshold. A depolarized neuron that has reached its voltage threshold â€Å"fires† at a level of intensity that remains unchanged, called the All-or-None principle, and as fast as 0.001 second. The brief wave of positively charged ions inside the neuron pushes the synaptic vesicles at the end of the terminal buttons, thereby releasing the neurotransmitters to the Synapse or the Synaptic Gap, the small gap between neurons. Neurotransmitters that are released in the synapse do not move in a predictive manner; rather, they randomly wander along the synaptic gap. Different neurotransmitters have different shapes, and the shapes serve as keys for opening the receptor sites at the dendrites of the receiving neuron. After the neurotransmitter activates the receiving neuron, they are then reabsorbed back in the synaptic vesicles of the terminal buttons of the releasing neuron. The re-absorption causes the neuron to get polarized and rest once again. In summary, the pre-synaptic neuron releases neurotransmitters that activate the post-synaptic neuron, which, in turn, releases neurotransmitters that can further activate other neighboring neurons. In this manner, electrical transmission is converted into chemical code, and back to electricity. This is the reason why the nervous system is characterized with electrochemical transmission. However, communication between neurons is not a linear path. Known as the Volley principle, a firing neuron can activate many neurons at once; vice versa, a neuron can be activated by the simultaneous firing of neurons that have different neurotransmitter types. Neurotransmitters are the chemicals released by a neuron to communicate with another neuron. They may be excitatory or inhibitory. Excitatory Neurotransmitters are those that activate other neurons to fire, while Inhibitory Neurotransmitters are those that restrain neurons to fire. There are currently fifty (50) discovered neurotransmitters. The six (6) types of neurotransmitters featured below are those that have major effects on behavior. * Acetylcholine or Ach is an excitatory neurotransmitter involved in muscular action, learning and memory. It is located throughout the central and peripheral nervous system. Low level of acetylcholine is associated with Alzheimers Disease, a degenerative disease wherein neurons die at a rate faster than normal. Up to date, no treatment has been found to cure this deadly disease. Drugs that supply ACh are only used to delay or reduce the rate of neuronal death. * Dopamine is an inhibitory neurotransmitter that controls voluntary movement, sleep, mood, attention and learning. Inhibition is a very important element for controlled action. Low level of dopamine is associated with Parkinsons Disease, wherein patients shake uncontrollably on different parts of the body. The disease is also degenerative, so that the shaking can range from mild to extremely uncomfortable. On the other hand, high level of dopamine is observed among schizophrenic patients. * Endorphinis an excitatory neurotransmitter involved in feelings of pleasure. Endorphins are called the natural opiates in the body and serve as pain killers especially on pregnant women during labor and delivery. High level of endorphins is also observed among long-distance runners and persons shocked from a traumatic accident. * Gamma Amino Butyric Acid or GABA is an inhibitory neurotransmitter that controls the electrochemical communication among neurons. It is located only in the central nervous system, and fills one-third (1/3) of the brains synapses. Low level of GABA is associated with anxiety. * Norepinephrine is both inhibitory and excitatory. It controls alertness and regulates sleep and wakefulness with ACh. As an inhibitory neurotransmitter, norepinephrine acts like GABA in preventing neurons from firing uncontrollably. As an excitatory neurotransmitter, it activates the heart muscles, the intestine and the neuro-genital tract. (For more information on how norepinephrine affects the body, consider reading about the endocrine system from the article â€Å"What are the Biological Foundations of Behavior?†) Low level of norepinephrine is linked with depression, while high level of norepinephrine is associated with agitation and mania. * Serotonin is an inhibitory neurotransmitter that works with Ach and norepinephrine in regulating sleep, mood, attention and learning. Just like norepinephrine, low level of serotonin is associated with depression.

Racism: White People and South Africa Essay

Compare and contrast between racism in Malaysia and South Africa. â€Å"Racism is man’s gravest threat to man – the maximum of hatred for a minimum of reason†, quoted by Abraham J. Heschel. As we know the history of racism is long and despicable one. The journey to overcome this obstacle that has plagued us for years is just as time consuming and the effort is overwhelming. A recent survey has showed that South Africa is the highest rate of racism among all the country. So now let us analyze the racism between Malaysia and South Africa. The most notable difference between the racism in Malaysia and South Africa is the oppression on women. Till today, men in Africa still hold the traditional perspective that women are like their property and subject to their abuse. The poverty Africa could be one of the main causes why women in Africa are still undergoing such a great deal of oppression unlike women in other areas. They were paid less for a greater amount of work and less benefits too. Sometime, they were dismissed without advance notice or termination pay. Besides, South Africa has the world’s highest level of reported rape – nearly half a million each year. So it is not surprising that South Africa is often called the â€Å"rape capital of the world†. It has shown that women in Africa typically hold lower status and normally weaker than men from physical and mentally. Therefore they are easily to be oppressed and exploited by African men. In Malaysia, the position of women today has greatly improved. The Government’s commitment to promote gender equality is evidenced by several policies, administrative decision and amendments to laws that have attempted to grant equal rights to women and to remove discrimination against them. It should perhaps be acknowledged that most of the changes made were in response to lobbying by women through unions, non-governmental organizations (NGOs) and other women’s groups. For example, in relation to employment rights, women teachers succeeded in getting the Government to adopt the principle of equal pay for equal work in 1967. Yet another difference between the racism in two different countries is discrimination of different race. In South Africa, there is a prohibiting marriage between white people and people of other races. It considers as â€Å"unlawful racial intercourse† and â€Å"any immoral or indecent act† between a white person and an African, Indian or coloured person. Blacks were not allowed to run businesses in those areas designated as â€Å"white South Africa† without a permit. They were supposed to move to their homelands and set up businesses and practices there. Transport and civil facilities were segregated. Black buses stopped at black bus stops and white buses at white ones. Trains, hospitals and ambulances were segregated. Even though black people were not allowed to employ white people in white South Africa. Since Datuk Seri Najib Tun Abdul Razak became the sixth Prime Minister, he introduced a concept of solidarity, which is One Malaysia. 1 Malaysia brought the aspirations to improve race relations to ensure that the people of Malaysia to forge closer unity. The basic thing that needs to be created in the spirit of solidarity is a feeling of respect, sincerity and mutual trust between the races. Therefore, our citizens give priority to the interests of national allegiance and loyalty to the people and solve their own group. For example, one Indian got hit by a reckless car while he was playing outside the house. Some of neighbors (few Chinese but mostly Malays) quickly rushed for help, and they really got angry with the driver and almost smacked him! Although the neighbors are Malays, they stood for an Indian neighbor. Furthermore, the difference of racism between Malaysia and South Africa is the education system. South Africa has a high-cost, low-performance education system that does not compare favorably with education systems in other African countries, or in similar developing economies. There is a multitude of well-publicized problems, including a shortage of teachers, under qualified teachers and poor teacher performance. In the classroom, this results in poor learner standards and results, a lack of classroom discipline and is exacerbated by insufficient resources and inadequate infrastructure. So it is not surprising that many South Africans are low-educated and paid for little salaries. Malaysia’s educational system generally promotes surface and passive learning instead of deep and active learning which are crucial for creating a quality learning environment. The products of our school system are generally ill-prepared either for higher education work or life in general. As we know, our students lack critical and creative thinking skills because our educational system promotes conformity and uniformity. Therefore, a lot of step in transforming our education system are done. For example, one of the crucial steps is begin with the end in our mind. So, Malaysian students and graduates can possess adequate disciplinary knowledge, be self-confident and achievement-oriented persuasive and effective communicators. In conclusion, here are the main three differences between the racism in Africa and Malaysia. Even though racism is wrong, it is still being practiced in this country and in others. The origins are obscure, but it most likely had something to do with the fact that early humankind thought â€Å"black† (because it resembled â€Å"night†) was bad and â€Å"white† (because it resembled â€Å"day†) was good. But our enlightened society has more discernment than this, and we know that a person is neither good nor bad depending on the color of their skin.

Food Pyramid Essay

A healthy diet is composed of several groups of foods. The United States government developed the food pyramid in 1992 to suggest nutrition guidelines and intake endorsements for each of the food categories. The foods that we consume on a daily basis fall into food groups. The United States Department of Agriculture recognizes six major food groups. These groups are grains, vegetables, fruits, meat and beans, milk and fats. The foods in these groups all play important roles in nutrition and health. In April 2005, the United States Department of Agriculture released the MyPyramid food guidance system, a restructure of the older food pyramid focused on making healthy food choices and leading an active lifestyle. Any food made from wheat, oats, rice, cornmeal, barely or a cereal grain is considered a grain product. Grains are also known as carbohydrates. Carbohydrates are the body’s primary energy source, which is the reason why grains are so important for our health. Foods such as pasta, oatmeal, cereal, bread and rice are grains. There are two types of grains, whole grains and refined grains. Whole grains are made from the entire grain. They are good sources of fiber, which help to reduce cholesterol levels and decrease the risk of heart disease. Refined grains are processed to remove parts of the grain known as the bran and germ, which strips the grain of most of its fiber and nutrients. Refined grains are then enhanced to add back iron and B vitamins. It is suggested at least half of grains eaten to be whole grains. Imagine there was a medicine that could reduce the risk of heart disease and stroke, lower high blood pressure, prevent vision and digestive-system problems, and possibly lower the risk of cancer. There is no real medicine that can do all that, but according to the Harvard School of Public Health, you can get all of those health benefits just by eating plenty of fruits and vegetables. Despite their health benefits, only 10 percent of people in the United States consume the correct amount of fruits and vegetables. Those that eat fruits and vegetables are much healthier. The primary reason you should consume enough meat and beans each day is because these foods supply you with a healthy dose of protein. Protein supports healthy growth and development, including the correct formation of muscle and tissue. Eating sufficient amounts of protein is a healthy way to boost your energy so you can be physically active as well. One of the most notable vitamins present in meat and beans is niacin, a B vitamin that helps turn food into energy. Niacin has also been noted to have an increase in good cholesterol. The primary mineral in meat and beans is iron, which you need to produce healthy red blood cells that are able to transport oxygen throughout your body. Beans supply more iron per serving than meat, but both foods are healthy sources of this mineral. Milk has a rich source of calcium and minerals that our body needs to build and maintain strong bones and teeth and assist in the proper contraction of our muscles. It also provides a large amount of vitamins A, B, and D, all of which help proper growth and development. The main reason why milk is so important to the human body is because of how much calcium it carries with it. Fat is frequently criticized as a cause of rising obesity rates and problems associated with extra weight, making many people think they need to avoid fat. In fact, fats are important in your diet for a number of reasons. Fats provide your body with energy and provide storage spots for energy in the body. Because your body can’t make certain essential fatty acids, it relies on your diet to provide them. In conclusion, the primary food groups are very essential to your body in order for it to be healthy. At the looks of it, if humans weren’t consuming any of these food groups on a daily basis, in the long run it would cause a very large number of health problems. The reason why the food Pyramid was created was to show people a healthier life style to live so they can hopefully improve their health and lifespan. In general, eating healthy foods like this makes your body feel much better and you are generally much happier.

Essay On Nanoparticles - 1066 Words

In recent years, inorganic and chemosynthesized superparamagnetic iron oxide nanoparticles (SIONPs) such as Fe3O4 magnetic nanoparticles (Fe3O4 MgNPs) have attracted extensive interest for their biocompatible (Kunzmann et al., 2011) and low toxic properties mainly in the human body studied (Jeng and Swanson, 2006; Karlsson et al., 2009) which make them as promising remedial tools in related fields. Magnetite nanoparticles is the most-studied for many technological applications in biomedicine, such as high sensitivity biomolecular magnetic resonance imaging (MRI) (Bulte et al., 2001), in vivo targeted drug delivery (Sunderland et al., 2006), hyperthermic agents and enhancer in the treatment and diagnosis of cancer (Gupta and Gupta, 2005;†¦show more content†¦Whereas, marine macroalgae have richness in minerals (Wells et al., 2017) that can be used for the greener route synthesis of Fe3O4-MgNPs, and as bionanofactories materials (LewisOscar et al., 2016) have the ability to ac cumulate metals and reduces ions, and could be the superior contender for biosynthesis of metallic NPs (Davis et al., 1998). However, the synthesis of stable Fe3O4-MgNPs using algae extracts are very complicated due to the high reactivity, high particle instability, great propensity of iron ions to oxidization and reduced with a wide array of various chemical compounds, and high tendency to aggregate into agglomerates within the solution (EL-Kassas et al., 2016; Makarov et al., 2014; Huang et al., 2007). In view of inorganic iron oxide nanoecotoxicity, little studies report in the human (mainly inorganic Nano-Fe3O4) (Jeng and Swanson, 2006; Karlsson et al., 2009) and existence the criteria to define the toxicity of nanomaterials does not guarantee that iron oxide nanoparticles pose no potential risks in a challenge with environmental systems and are suitable for use in widespread applications. Hence, due to theirShow MoreRelatedNanoparticles Essay1011 Words   |  5 PagesNanoparticles are materials with overall dimensions less then one hundred nanometers, they are also known as zero-dimensional materials. 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