Tuesday, December 10, 2019

Action potential free essay sample

The formation of an action potential can be divided into five steps. (1) A stimulus from a sensory cell or another neuron causes the target cell to depolarize toward the threshold potential. (2) If the threshold of excitation is reached, all Na+ channels open and the membrane depolarizes. (3) At the peak action potential, K+ channels open and K+ begins to leave the cell. At the same time, Na+ channels close. (4) The membrane becomes hyperpolarized as K+ ions continue to leave the cell. The hyperpolarized membrane is in a refractory period and cannot fire. (5) The K+ channels close and the Na+/K+ transporter restores the resting potential. Action potentials are formed when a stimulus causes the cell membrane to depolarize past the threshold of excitation, causing all sodium ion channels to open. When the potassium ion channels are opened and sodium ion channels are closed, the cell membrane becomes hyperpolarized as potassium ions leave the cell; the cell cannot fire during this refractory period. This negative potential is the resting membrane potential of the cell. This is the resting membrane potential before the action potential begins. In response to a depolarizing stimulus, some of the voltage-gated Na+ channels become active and membrane potential become less negative until it reaches threshold potential. Any stimulus if strong enough to reach the threshold potential will lead to depolarization stage. When the threshold potential is reached, more voltage-gated Na+ channels are open and membrane suddenly becomes very permeable to Na+, allowing tremendous numbers of positively charged Na+ to diffuse to the interior of the axon. More sodium ions move into the nerve cells via voltage-gated Na channel (Resting to activated state). This will lead to membrane potential become more positive or less negative. The membrane potential rising rapidly in the positive direction. This is called depolarization. Within a few millisecond after the membrane becomes highly permeable to Na+, the Na+ channels rapidly enter a closed state (inactivated state) and k+ channel will enter its active state. Opening of voltage-gated K+ channels causes rapid diffusion of K+ to the exterior re-establishes the normal negative resting membrane potential. The repolarization stage is when the voltage-gated K channel open. Potassium ion move out from the nerve cells. This will establish normal negative resting membrane potential. Finally, slow return of potassium ion gated channel to the closed state, causing an excessive efflux of potassium ions. This efflux causes hyperpolarization of the membrane. Hyperpolarisation ensure the action potential move in one direction as it create a refractory period for the membrane. Than the membrane potential will return to the resting membrane potential. Describe the steps in neuromuscular transmission An action potential is initiated and propagates along motor neuron to the presynaptic terminals. The presynaptic terminal is depolarized causes voltage gated. Ca2+ channels in the presynaptic terminal to open. Ca2+ enter into the terminal causes the synaptic vesicles to fuse with the presynaptic membrane, resulting in the release of Acetylcholine (Ach) into the synaptic cleft by exocytosis. Ach diffuses across the synaptic cleft and binds to nicotinic receptors on the motor end plate. This binding cause the ligand-gated channel open and the flow of ions occurs. The Na+ flow into the cell and K+ flow out of the cell.Depolarization accour bcz more na+ move in than K+ move out. This flow of ions generate the end plate potential (EPP). When EPP had achieved certain membrane potential, the voltage-gated sodium channel open and cause the flow of Na+ into the cell. Muscle action potential is generated. Generation of EPP, local currents depolarize the adjacent muscle cell membrane to its threshold potential Generates an AP that propagates over the muscle fiber surface and into the fiber along t-tubules. This couses the sarcoplasmic reticulam to release ca2+ in which initaite the muscle contraction. Results in muscle contraction

Tuesday, December 3, 2019

Macbeth And Hamlet Essays - Characters In Macbeth,

Macbeth And Hamlet Macbeth is a Shakespearean tale about a confused Scottish noble that does not know how to utilize his ambition. He succumbs to temptation, which is partly supplied by his wife, and he kills to get the position of king. Hamlet, on the other hand, is another Shakespearean masterpiece that deals with a torn prince of Denmark that has to deal with the untimely death of his father. Hamlet and Macbeth are similar in many ways, and reveal many sides of the human heart through their dynamically dramatic plots. Both of these works deal with great inner conflict in the main character. Macbeth cannot decide whether or not to kill Duncan, who is the king of Scotland. He sees an imaginary dagger floating in front of him that is a figment of his imagination, which portrays how much he is lamenting over the act of genocide. He finally commits the murder, and gets the position that he longs for. The main conflict that Hamlet has to deal with, portrayed by his fated "To be or not to be..." speech, is how to deal with the suspicious death of his father - by suffering the ills of this world or taking resolute action against them. Both stories carry with a great amount of deceit. With Macbeth, the witches explain that no one born of a woman will ever kill him. Macduff, his slayer, was born by a Cesarean section. Of all the things that the witches tell him, all are true, but are spoken in confusing riddles that are misleading. The witches trick him into believing that he and his descendants will rule the land forever. Hamlet's father is killed by his uncle, which is revealed at the end. Hamlet is tricked into going to England where his uncle orders him to be executed, but Hamlet is clever enough to get out of that predicament. Each of these tales deals with many tragic deaths. Macbeth is killed in the end for the folly of having misdirected ambition. Lady Macbeth is also killed, and Macduff's family is senselessly wiped out simply for Macbeth's conquest. King Duncan is murdered so that Macbeth can acquire his position as king. In Hamlet, the prince is slain by a poisoned sword blade. His father is the victim of a power hungry uncle. A poisonous drink meant for Hamlet senselessly kills Hamlet's mother. Ophelia, Macbeth's girlfriend, goes insane and commits suicide because of the events that take place through the harrowing plot of this work. As it is plain to see, these are extremely dynamic literatures. The two have a few differences, but mostly have points that are common. The inner conflict, deceit, and tragic deaths that compose the stories spur the tales on and add immeasurably to the plot. These three core elements drive each story to its moral and never let up. Without one of these included in each, the story line would suffer greatly and not have the impact that each does.

Wednesday, November 27, 2019

Essay on belifs in fasting

Essay on belifs in fasting Essay on belifs in fasting Assessment reading RAF 2 and 5 6) The righter suggest that she is a nice calm wife and likes her husband very much but he did not give much information but. The mood changes drastically after the husband says "sit down he said just for a minute, sit down’. I think Mrs Maloney's mood changed then to cold and frightened to what is to come because Mr Maloney was strange and not caring or loving when he walked thru the door I know this because it states " Tired darling ? 'Yes,' he said I'm tired." This was quite snappy and carried on like that until he Brock up with her a pregnant woman he is leavening then Mrs Maloney killed him with the frozen lamb leg that was when she felt guilty and all thoughts on her being loving caring and just a plain nice person with nothing to hide but now she has got everything to hide and all she thought about was getting an alibi sloshes wasn't guilty for what she had done and cold and calculating but so much different than she was at the being or even that sad just need to get cle an and get away with what she has done witch wasn't hard because she probably learnt things along the way with her husband being a police officer. 7) He creates mystery in a clever way such as the name "lamb to the slaughter" I can imagine a lamb getting killed not the lamb doing the killing. He does this so it can surprise you and make it very interesting to the reader. Things that make me want to read more and make me more interested to know what is going to happen next "sit down he said. Just for a minute it wasn't till then that she began to get scared". I think that was the most existing bit in the story because you know something is going to get killed and that seemed like the moment for something to get killed and you think it can't get worse but it

Saturday, November 23, 2019

Thesis Statement On How Edgar Allan Poes Writings Illuminate His Upbringing

Thesis Statement On How Edgar Allan Poes Writings Illuminate His Upbringing My thesis statement is that Edgar Allan Poe's writings illuminate his upbringing. His writings illuminate his upbringing because his childhood was very hard, full of darkness, and he never experienced love from a parent. Therefore he thought the world was like his life was, dark and dreary. So that is why his stories are always sad, and full of heartbreak.The writings by Edgar Alan Poe are for the most part sad, dark, dreary, and mysterious, they are just like how his life was. After the age of two Poe never had real parents only people who looked after him after his parents died. He didn't know if his home was only temporary or if it was for good, for all he knew the people he was living with could kick him out of their house and stop supporting him. He lived his life day by day not knowing what the next day would bring or if he would have a house to live in the next day.English: Edgar Allan Poe's room

Thursday, November 21, 2019

The high salaries paid to CEOs are not justified. To what extent do Essay

The high salaries paid to CEOs are not justified. To what extent do you agree with this statement - Essay Example The high compensations are in the forms of high salary, bonuses or stock plans. The performance of the CEO has no quantifiable effect on corporations’ performances as the remuneration has little or no effect on the performance of the CEO (Lys, Rusticus and Sletten, 2007). As mentioned above, the only quantifiable effect is the widening gap between them and the other management people on whom the CEOs depend to produce positive performance of the company. In an article in Business Week, during the 1980s the average pay of a CEO was 42 times more than the hourly wage paid to a worker (Finch and Bowers, 2009). As the business entered the 1990 era, this multiplication grew to 85 times more than average hourly pay of a worker which reached the astonishing height of 531 times in 2000 (Finch and Bowers, 2009). What caused this hike in the salary of the CEOs and was this hike justifiable? This question remains unanswered to this day although many studies have been carried out on a lin k between CEO performance, company performance and the pay scale. Researchers such as Daines, Nair and Kornhauser (2005) tried to define measurements for CEO skill. They wanted to isolate the specific factor for CEO competence that can be used to justify the compensation and company performance. According to Daines, Nair, and Kornhauser (2005), the performance of any corporation does not depend only on the CEO skills or performance but also depends on other factors such as the economy, regulations, and conditions of the industry and so on. They hypothesized that a company managed by a skilled CEO should be performing better than the competitors in its industry. This hypothesis is based on the belief that if a company is managed by a poor CEO, the company’s performance will be poor and vice versa. The results of this research were informative. The economic performance and CEO salaries for the years 1990-2002 were studied which showed that small business

Wednesday, November 20, 2019

Generating electricity Assignment Example | Topics and Well Written Essays - 2500 words

Generating electricity - Assignment Example Most of the energy is generated in large power stations located too far from where the energy is in use. Therefore, they rely on the importation of energy so as to meet the increasing demand. Electricity is imported from New Zealand, which is characterized by a series of generation plants, and transported to the region through the national grid (David 2002). Natural gas from Taranaki is piped via a series of underground gas pipes and lines, whereas, petrol and aviation fuel produced at Marsden Point Refinery is conveyed to the county via a single pipe. Auckland portrays strong energy demand since the war characterized by high costs of transportation of fuel, increasing reliance on imported energy and low resilience towards altering energy supplies. The council has recognized that Auckland’s continued dependence on imported energy and the lengthy supply chains will pose risks to the future energy security of the country. Therefore, they must appropriately manage their energy so urces by ensuring proper land use decisions are made on the understanding of the current peak oil demand, and the perception of the climate change. Implications of Erecting Additional Transmission Lines The need to invest in the national grid For Auckland wellbeing and continuous economic performance, a secure energy source and supply is required. All the families and business in the region rely on the existence of a dependable energy supply in the form of electricity, gas or in other form. There is a high likelihood of Auckland’s demand for energy to rise in the future. Therefore, Transpower has to ensure that there are sufficient energy sources to meet the rising demand. Security of energy supply in Auckland has raised significant economic issues. There have been various challenges that have raised concern, for example, in 2006 extreme weather conditions lead to a failure at Otahuhu substation disrupting power supply to a large part of Auckland (Ray 2012). The majority of t he Auckland community needs the continuous supply of electricity. It is not only the residential and commercial markets that depend on electricity but also the entire activities of the country. The community’s public utility base or infrastructure relies on the uninterrupted supply of electricity. Other parts like water and waste treatment, schools, hospitals and ports heavily depend on electricity for efficient operation of their activities. Without electricity, the security and safety, health and environmental conditions are adversely compromised. Cost and funding implications Any project designed or implemented will experience and, therefore, meet some costs during the process, which will demand internal and external funding to complete the project as desired and fulfill all specifications and requirement expected. The choosing of a funding system will significantly affect the individual and state contribution to the share of the financial report. Although these effects ma y be negative, they also show the outcome levels achieved by the system, who receives formal support and the level of support given or received. Funding can be tendered by either private or public or both at the same time. Each system is always affected by both political and economical judgments (Sowell 2011). In choosing a funding system, the first criterion is to assess the performance of available

Sunday, November 17, 2019

Falconi removals business Essay Example for Free

Falconi removals business Essay Falconi removals business I will choose for them location in my area Harehills road because is good busy place. Is good connection to big local stores as continental, electrical superstores. Falconi business is depending now much works them received from customers. I think Harehills area will give those lots local customers who moving the houses or being stuff from shop. Falconi can find unemployed people and give them job. Harrehills area is more cheap then for example city centre and they can safe more money from renting office or buy cheaper place for business in this area. The most important point to make Falconis business is not more removal company there. They will not have concurrency in business. Economies of scale- are the cost advantages that a firm obtains due to expansion. Diseconomies of scale are the opposite. Economies of scale may be utilized by any size firm expanding its scale of operation. The common ones are purchasing managerial, financial and marketing. Each of these factors reduces the long average cost (LRAC) of production by shifting the short-run average total cost curve down and to the right. The local labour force- The labor force is the number of people employed and unemployed. Participation rate is the ratio between the labor force and the overall size of their cohort. In the West during the latter half of the 20th century, the labor force participation rate increased significantly, largely due to the increasing number of women entering the workplace. Local employment levels- local unemployment rate may play a part in the decision where to locate. Uk currently has one of the lowest unemployment rates in Europe. However, unemployment is not evenly spread and some parts of the country have high levels of unemployment like Northern Ireland, parts of west Cornwell and the north-east of England. Wage and salary levels- for some firms wages account for a significant proportion of their total cost so a business may decide to locate in an area of relatively low wages, Wage in south-east of England tend to be higher then in south Wales. These areas tend also to be areas of above average unemployment as workers are keen to find work and are prepared to accept lower wages. Nearness to customers- There are a limit to how far customers will travel to buy fish and chips even if they are excellent quality. Fish and chip shops will need to be situated in area where plenty of local customers are. Debenhams will only consider locating a new store in an area of relatively high population. Nearness to suppliers- for some businesses near suppliers of key raw materials and components may be the main factory where to locate. Over the years a wide range of suppliers have grown up in area such as companies supplying electrical fittings and other important components. Up until 1979 the uk imported all of its crude oil. Historical reasons for location- In an area a business may be reluctant to reluctant to relocate, with all the expense and upheaval that this involves. During the 18th and 19th centuries a large number of pottery and earthenware business set up in the area because of the availability of suitable fireclay. Demographic change- Over the thirty years some parts of the country have experienced increases in population as people move into the area in search of work. These demographic changes will have a significant impact on local the business.

Action potential free essay sample

The formation of an action potential can be divided into five steps. (1) A stimulus from a sensory cell or another neuron causes the targe...