Cardiovascular System in Parabolic Flight and Spaceflights

Cardiovascular System in Parabolic Flight and Spaceflights Human Spaceflight: Alterations of the cardiovascular system during parabolic flights and spaceflights The purpose of this research is to identify the changes occurring during parabolic flights and spaceflights, where theres weightlessness. The importance of the cardiovascular system in space, is recognised as well as some of its fundamentals based on past researches. In addition, since parabolic flights are a way of experimenting physiological alterations in the human body, instead of actual spaceflights, the procedure needed for the airbus to reach microgravity conditions is indicated as well. Findings, such as low plasma volume, circulatory pressure, central venous pressure, stroke volume and also the heart rate of the cardiovascular system are stated from past investigations. Also countermeasures, such as exercise and diet are also briefly discussed. Introduction Microgravity is the phenomena where objects or people experience weightlessness. Astronauts and objects face microgravity in space, where the gravity is very small (micro) and they float (free fall). Even though astronauts are relatively heavy, they can move easily inside or outside the spacecraft (Wall, 2015). Under microgravity circumstances, the physiology of the cardiovascular system changes and it reacts unlikely relative to the gravity of the Earth leading to body alterations such as redistribution of blood, cardiac arrhythmia and orthostatic hypotension (Zhu, Wang, and Liu, 2015).These changes may occur pre-flight, in flight or post-flight and they may impact the astronauts health. Moreover these changes can affect either healthy astronauts or astronauts with past heart diseases. Due to the environment, the body of the astronaut learns how to adapt under the new conditions and works relatively quickly. In order to investigate and analyse the changes of the human physiology, various microgravity based researches were conducted, not only by spaceflights but also by parabolic flights and bed rest studies. Measurements are taken in three stages of the astronauts body, pre-flight, in-flight and post-flight, known as the long duration since astronauts are sent to space missions while these measurements are taken. Although, for more data, investigators managed to create microgravity condition for 20-30 seconds, using parabolic flights, known as the short-term duration, which is clearly a cheaper way to collect data. Another way to study the adaptation of human physiology in space is bed rest studies, where volunteers spend up to 2 months in a bed, with their head end at an angle of 6ÂÂ ° beneath the horizontal axis. All volunteers eat, shower and exercise while they are in bed. The cardiovascular system In order to analyse the cardiovascular system in space, some fundamentals of the heart should be noted. A healthy cardiovascular system is essential for astronauts going to space, since the heart functions differently in microgravity and it is responsible for many main functions of the body. The physiology of the cardiovascular system in space, therefore will be altered and this can impact the function of the system. Transporting nutrients (e.g. oxygen O2, food) to the tissues of the body, waste removal (e.g. carbon dioxide CO2, by-products) and controlling heat distribution between the body core and the skin (temperature) are some main function of the cardiovascular system (Evans, 2012). Heart is one of the muscles in our bodies which is constantly in action and it is part of the cardiovascular system. This system also includes arteries, veins and capillaries, all known as blood vessels. Additionally, O2 and CO2 are delivered and collected, respectively, to and from various organs, through blood vessels pumped by the heart.ÂÂ   Furthermore, the cardiovascular system is responsible for the blood pumped towards the heart, due to the muscles of the legs (Evans, 2012). The cardiovascular system in weightlessness When an astronaut is bare in space, the cardiovascular system learns how to function in such an environment.ÂÂ   The cardiovascular system changes in microgravity, since the downward force of gravity does not exist anymore, as it existed on Earths environment. Therefore, due to the lack of the gravitational force, blood and body fluids are not uniformly distributed in the body, but more importantly in the legs, where all these fluids shift upwards, towards the head, resulting for astronauts to have puffy faces and less leg circumference (bird legs), as shown in Figure 1. Fluid shift in the body, leads to the increase of the size of the heart, initially, in order to handle the increase of the blood flow. This occurs during the first day of exposure in microgravity. In addition, due to the upward direction of the fluids, astronauts do not feel as thirsty, resulting to the reduction of the fluid levels after the first day and the heart shrinks (Lujan, Bartner, and White, 1994). Figure 1: Illustration of fluid shift level. The fluids are distributed uniformly, pre-flight (left), fluids shift, during flight (bird legs and puffy faces)(middle) and post flight, the pressure is lower in the upper body, due to gravity, causing faintness to the human. (Watenpaugh and Hargens, 1996) Parabolic flights and the cardiovascular system Airbus A300 Zero G is the aircraft used by the French company Novespace for simulation of microgravity through parabolic flights, between 1997 and 2014 as shown in Figure 2. Agencies such as the European Space Agency (ESA) and the German Aerospace Centre, performed researches using this airbus in the stated period of time, but by 2015 the new Airbus A310 Zero G replaced it. Figure 2: The Airbus A300 ZERO-G as it is flying in an incline of 40ÂÂ ° to reach 0g. (Pletser, et al., 2015) These aircrafts, were built for researches due to testing results before or after space missions, by achieving parabolic flights under weightlessness for 20 seconds (Pletser, et al. 2015). More specifically, the airplane from a steady horizontal altitude, pulls up at an angle approximately 40ÂÂ ° in a period of 20s, resulting to an acceleration between 1.8 g and 2 g and therefore, the engines start to slow down, which leads to microgravity conditions inside the aircraft as it reaches the peak of the parabola. Finally, the aircraft generates an acceleration of 1.8 g to 2 g, while flying back down with roughly 40ÂÂ ° again for 20s and then before returning to its initial steady altitude, repeats the manoeuvre from the beginning, as shown in Figure 3 (ESA, 2004). In addition, parabolic flights can investigate how the cardiovascular system of the human body reacts under 0-g conditions, within this period of time by spending relatively less money than actual spaceflights. Figure 3: This figure illustrates the manoeuvre which the aircraft (thick-black line) follows to generate microgravity conditions and demonstrates the acceleration and the microgravity level as well. (ESA,2004) Between 2010 and 2012, Novespace undertook an experiment based on the reaction of the cardiovascular system during a parabolic flight, using the Airbus A300 Zero-G. The test presents a short duration of microgravity, where the fluids inside the body are distributed. The heart is pumped with more blood than usual resulting to an increase of the blood pressure in the ventricles of the heart. The stoke volume of the cardiovascular system remained constant but the heart rate decreased by 14 min-1. Furthermore, it was stated that astronauts were in an environment, where the body lacked sufficient oxygen supply, known as hypobaric hypoxia condition (HH) and since the study is under a parabolic flight, the gravity was shifting as well. This kind of environment influenced the cardiovascular system, where the data obtained for the plasma volume showed a decrease mostly due to HH, from -52 ml (hypobaric chamber) to -115 ml (parabolic flight) (Limper and Gauger ,2014). Another research, compare d the data for humans in supine posture, under normal gravity and microgravity in parabolic flight (0G), which showed an increase in cardiac filling pressure resulting to the diameter of the left atrium to increase by 3.6 mm. At the same time the central venous pressure (CVP) decreased by 1.3 mmHg but the transmural CVP increased by 4.3 mmHg. Finally, as soon as an astronaut returns to Earth, due to the gravity, the blood flow is reduced and that can cause the astronaut to collapse (Watenpaugh and Hargens, 1996). These results were obtained by researches, in order to investigate the consequences of the cardiovascular system under weightlessness, by avoiding actual spaceflights, where these changes are only temporarily. The cardiovascular system during spaceflights As soon as astronauts enter space, the fluid levels in the body are not uniformly distributed as they were on Earth, which results to alterations of the cardiovascular system. As it was mentioned in parabolic flights, the astronauts are under hypobaric- hypoxia conditions, meaning that the oxygen saturation decreases (SaO2) and hence the oxygen in the blood. It has been stated that the concentration of O2 in the blood can drop down to 75%, where usually this levels should be more than 80%, but if the astronauts stays in space for longer, this concentration will increase back to 85% (Opatz and Gunga, 2014). Moreover, the mass of the heart decreases during spaceflights and therefore the heart rate is less than that on Earth. In 1996, it was reported that the heart rate would increase as the astronaut continuous to be under microgravity circumstances, during a long-term spaceflight (Charles, Frey, and Fritsch-Yelle, 1996). In weightlessness, significant effects were also realised, the c ardiac output increased whereas the systolic and diastolic pressure decreased (Hamilton, Sargsyan, and Martin, 2011). Hence, stroke volume is also reduced, due to hypovolemia which is responsible for hypotension and atrophy of the heart (Levine, 1997). Investigators postulate that plasma volume decreases from the first day and it continuous to reduce throughout the whole spaceflight by 17%. This occurs, because of the negative fluid distribution and the fluid movement towards the extravascular space and therefore the orthostatic intolerance (Alfrey, Udden, and Leach- Huntoon, 1996). A study reported by J.C Buckey et al. 1996, studied the central venous pressure (CVP) in space and stated that the CVP increases during the launch and more in the spaceflight. The left ventricular end-diastolic volume (LVEDV) was also analysed in order to figure out how it is affected by microgravity. Furthermore, it was stated that as astronauts enter space, the LVEDV and therefore the total heart volume increases significantly. While the astronaut is in space, the body adjusts to the environment resulting to the LVEDV to decrease (Buckey Jr. and Gaffney, 1996) Countermeasures For short duration exposure, effects are less than actual spaceflights where the duration could be more than 6 months. It is really important for astronauts to be healthy during a mission, therefore some actions should be taken in order to counteract these threats of their physiology. It has been reported that somatic stress in weightlessness effects the cardiac arrhythmia (Romanov et al., 1987). The astronauts must exercise and have a healthy diet, before and during the spaceflight, to ensure the appropriate volume for extravehicular action (Hargens, 2009). Also, the lower body negative pressure (LBNP) should be exercised regularly since it increases the plasma volume (Watenpaugh and Hargens, 1996) and in fact, aerobic exercise keeps the aerobic volume (peak of VO2) constant. For long-term exposure in microgravity, exercising machines, provided in the spacecraft can reduce the consequences of the physiology of the astronaut after returning to Earth. Although, studies have not shown the particular amount and type of exercise, that astronauts should perform, yet (Schneider and Watenpaugh, 2002). Discussion and Conclusion Researches within the last 20 years, examined how the cardiovascular system adapts under microgravity conditions, in order to provide astronauts with a safe working environment and physiology. Astronauts are sent to space to test experiments for the future of science, but their lives shouldnt be at risk. Due to microgravity, several characteristics of the cardiovascular system are affected. The fluids in the body of an astronaut exposed in microgravity, shift head-wards due to the missing gravitational force. Therefore, plasma volume and mean circulatory filling pressure are decreased. Hence, there are effects on the central venous pressure (CVP) and stroke volume, which both are reduced during weightlessness. The heart rate is also declined due to these changes, in order to maintain the arterial blood pressure and metabolism. Some of these parameters can affect significantly the astronauts health and in rare cases may lead to tragedies, since they are long- term flights. Although, w hen subjects are under investigation in parabolic flights, these changes are only temporarily. Also, countermeasures, such as aerobic exercises and healthy diet, before, during and after the spaceflight are required. These actions may reduce the orthostatic hypotension of astronauts during flights but also as they return back to Earth. More experiments will be conducted in the future, where researchers will have an even better understanding of space environment and the physiology in it. References Alfrey, C.P., Udden, M.M. and Leach- Huntoon, C. (1996) Control of red blood cell mass in spaceflight, Journal of Applied Physiology, 81(1), pp. 98-104. Buckey Jr., J.C. and Gaffney, F.A. (1996) Central venous pressure in space, Journal of Applied Physiology (1985), 81(1), pp. 19-25. Charles, J.B., Frey, M.A. and Fritsch-Yelle, J.M. (1996) Cardiovascular and cardiorespiratory function, Space biology and medicine. Reston (VA): American Institute of Aeronautics and Astronautic, , pp. 63-88. ESA (2004) What happens to the human heart in space? Available at: http://www.esa.int/esapub/bulletin/bulletin119/bul119_chap4.pdf (Accessed: 2014). ESA (2015) Bedrest and ground studies. Available at: http://www.esa.int/Our_Activities/Human_Spaceflight/Research/Bedrest_and_ground_studies (Accessed: 30 January 2017). Evans, J.D.W. (2012) Crash course cardiovascular system, 4e (crash Course-UK). 4th edn. Edinburgh: Elsevier Health Sciences. Hamilton, D.R., Sargsyan, A.E. and Martin, D.S. (2011) On-orbit prospective echocardiography on International Space Station crew., Echocardiography, 28(5), pp. 491-501. Hargens, A.R. and Richardson, S. (2009) Cardiovascular adaptations, fluid shifts, and countermeasures related to space flight., Respiratory Physiology Neurobiology, 169, pp. 30-33. Levine, B.D. (1997) Cardiac atrophy after bed-rest deconditioning: a nonneural mechanism for orthostatic intolerance, Circulation, 96, pp. 517-525. Limper, U. and Gauger, P. (2014) Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight, European Journal of Applied Physiology, 114(6), pp. 1281-1295. Lujan, B.F., Bartner, H. and White, R.J. (1994) Human physiology in space : a curriculum supplement for secondary schools. Washington, D.C. : National Aeronautics and Space Administration: . Opatz, O. and Gunga, H.-C. (2014) Human physiology in extreme environments. San Diego, CA, United States: Academic Press. Pletser, V. and et al. (2015) European parabolic flight campaigns with Airbus ZERO-G: Looking back at the A300 and looking forward to the A310, Advances in Space Research, 56(5), pp. 1003-1013. Romanov, E.M. and et al. (1987) [Results of long-term electrocardiographic examinations of cosmonauts, Kosm Biol Aviakosm Med, 21, pp. 10-14. Schneider, S.M. and Watenpaugh, D.E. (2002) Lower-body negative-pressure exercise and bed-rest-mediated orthostatic intolerance, Medicine and Science in Sports and Exercise, 34, pp. 1446-1453. Shelhamer, M. (1996) Parabolic flight as a spaceflight analog, Journal of Applied Physiology, 120(12), pp. 1442-8. Wall, J. (2015) What is Microgravity? Available at: https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-microgravity-58.html (Accessed: 30 January 2017). Watenpaugh, D.E. and Hargens, A.R. (1996) The cardiovascular system in microgravity, Handbook oh physiology : Environmental physiology, , pp. 631-674. Â   Â   Zhu, H., Wang, H. and Liu, Z. (2015) Effects of real and simulated weightlessness on the cardiac and peripheral vascular functions of humans: A review., International Journal of Occupational Medicine and Environmental Health, 28(5), pp. 793-802.

George Washington Proclamation Of Neutrality

Washington's Proclamation of Neutrality George Washington's decision to announce a policy of neutrality benefited the e nation because it protected them from foreign enemies and it prevented riots and in correction between political parties. The proclamation of neutrality, issued in 1 793, was published to Stay neutral between the French and British during their war and became the foundation f American policy toward Europe until the twentieth century.Both American political parties ink ewe that they were too weak to get involved in a war and too dependent on British trade. They gag reed that the United States could bankrupt the federal government if they entered the con flick. This policy of neutrality prevented the nation from being too attached to another, as stated in Washington's Farewell Address, â€Å"so likewise, a passionate attachment Of one nation for anon her produces a variety of evils. This decision also prevented the United States from creating enemies with the opposin g nation. Washington also wanted to announce a policy of neutrality b teen political parties. He states in the Farewell Address, â€Å"It agitates the community with LIFO ended jealousies and false alarms, kindles the animosity of one part against another, foments occasionally riot and insurrection.It opens the door to foreign influence and corruption, which find s a facilitated access to the government itself through the channels of party passions. Thus the policy and the will of one country are subjected to the policy and will of another†¦ † This pass age explains how the dispute between the political parties will create riots between the people. Washington's decision to announce a policy of neutrality benefited the nation in numerous ways.

The Use Of Performance Enhancing Drugs Popularly Known As...

Management of doping in sport Student’s name Professor Course Date Literature review Introduction The current issue in sport particularly athletics is the use of performance enhancing drugs popularly known as doping. Spectacular doping cases have risen in the sporting arena that has caused unexpected situations and annoyed the public who are the fans. People have limited knowledge regarding doping though it is an ancient time issue. As a result, some people believe that all professional athletes have always been doped to achieve the standards of good performance and even compete and win in most of the great tournaments (Anderson, 2013). However, the number of athletes that have been positively tested has been small and almost non-representative thus raising suspension that only a few athletes are the influence of drugs. This is not therefore enough to make a generalized conclusion concerning the world of sports. Overview of doping The high rewards in selective tournaments require that competitors possess some features such as high level of practice and sacrifice regarding energy and time. Others have gone to the extremes of using questionable methods and behaviors in pursuit of these rewards and depending on the sleekness of the fruits; the contestants have gone on to engage in more practices to get there. Some of these activities are against the organizer’s interest, for instance, the use of steroids and other products to enhance performance by professional athletesShow MoreRelatedDrug Abuse8640 Words   |  35 Pagesthe report on ‘drug abuse’ has been made by our group to give an idea of the calamitous cause of using drugs in improper way. The report is intended to serve the purpose of providing the knowledge about drug abuse and to suggest ways to help limit drug abuse. An effort has been made on our part to include certain symptoms which indicate drug abuse. Also thr oughout the report, repetitive use of the drug abuse’ has been made to instate into the minds of the reader the cause of using drug abuse in an illicit

Rhetorical Analysis Of I Have A Dream Speech - 1198 Words

The, â€Å"I Have a Dream† speech given by Dr. Martin Luther King Jr. is arguably the most emotionally moving and persuasive speech of all time. But, to understand the speech one must first understand the context. At this time, the slave era was far gone but, not forgotten. Negro men and women were still experiencing segregation in the 1960’s. There was negro bathrooms, negro schools, negro water fountains, and even negro restaurants. Martin Luther King Jr. was an influential black man who took on the fight for equality. King presents his speech to a crowded Lincoln memorial — the same Lincoln who delivered the Emancipation Proclamation which freed enslaved Negros in the south nearly a hundred years before. King’s speech, later known as the, â€Å"I†¦show more content†¦Why has nothing improved? We as humans are always improving, so when King points out this fact it is an immediate red flag. Logos is used throughout the message to persuade the au dience as well as establish credibility to the speaker. Ethos is the second point of the rhetorical triangle. Ethos is the credibility of the speaker or the persuasion that a speaker is credible. Ethos is essential to the message of the speech because if a speech is not credible then how can any of the points be perceived as true. King establishes himself as credible by including facts that were commonly known as true. For example, the Negro was not free and everyone was aware of the prejudice. By saying these commonly held facts King establishes himself as a reliable source. The last and most prominent aspect of the rhetorical triangle is pathos. Pathos is the use of emotion in trying to persuade an audience. Pathos is in the words, in the delivery, and also in the situation. King’s speech to Washington D.C. that day sparked a flame of emotion that fueled the walk on Washington for black rights. Dr. King used many key, emotional, words and phrases to help persuade his audien ce. In line four, the very beginning of his speech, he begins with five score years ago. Curiously that sounds incredibly close to the address given by President Lincoln. The same man who set the negro slaves free. He uses this famous line to get people thinking about the current situation comparedShow MoreRelatedRhetorical Analysis Of I Have A Dream Speech924 Words   |  4 Pagesis his â€Å"I have a dream† speech. The reason â€Å"I Have a Dream† speech made massive impacts, is due to It struck directly into the hearts of Americans both black and white making America realize just what is really going on in this world. King informed people about racial equality and fairness. This speech hit home so well just by the way he structured his speech. You can notice that MLK structures his speech to appeal to the different types of audience, supporting it with the three rhetorical modes;Read MoreRhetorical Analysis Of I Have A Dream Speech752 Words   |  4 Pages28, 1963 At the Lincoln Commemoration 200,000 individuals accumulated after the Walk on Washington. This is the place Dr. Martin Luther conveyed his discourse I Have a Dream to America. He talked about the treacheries of isolation and separation of African Americans that was occurring in our country. In his first explanation he stated, I am happy to join with you today in what will go down in history as the greatest demonstration for freedom in the history of our nation. In this announcement heRead MoreRhetorical Analysis Of I Have A Dream Speech1058 Words   |  5 PagesMartin Luther King Jr’s â€Å"I have a Dream† demonstrates the combination of the rhetorical appeals to support his argument for equality and social justice because he draws attention to the past history of America’s Injustice and oppression towards black Americans. One of the explanations that the I Have a Dream address by Martin Luther King Jr. is memorable is that it contains a superb balance of Ari stotles 3 rhetorical appeals: attribute, pathos, and logos. Ethos is associate charm to authorityRead MoreRhetorical Analysis Of I Have A Dream Speech1061 Words   |  5 Pagesleader in the Civil Rights Movement. He is widely known for his speech that took place on 28 August 1963, â€Å"I Have a Dream.† This speech aimed toward the entire nation. King’s main purpose in this speech was to convince his audience to demand racial justice and for them all to stand up together for their rights. In this speech, King uses emotional and logical appeal to gain the audiences support. He applied many rhetorical devices to his speech to connect with the audience’s emotions, and to logicallyRead MoreRhetorical Analysis Of I Have A Dream Speech900 Words   |  4 PagesThe speaker of this essay that I will be writing about is Martin Luther King Jr. He was born on January 15, 1929, in Atlanta, Georgia at his family house. He was an American Baptist minister and activist who became the most visible spokesperson and leader in the Civil Ri ghts Movement. Martin Luther King Jr. was a great American, worked for civil rights in the United States in the 1950s and 60s. He became so popular and well liked that he was hated just as intensely by those who disagreed with theRead MoreRhetorical Analysis Of I Have A Dream Speech865 Words   |  4 Pagesin history. Throughout his speech, King employs many rhetorical devices that further his appeal for civil rights. King establishes his credibility as soon as he steps to the podium. King, an American civil rights activist and leader, was already known by the American people for his leadership throughout the civil rights movement. His leadership role as a civil rights activist asserts his message as credible and true to the American people. King’s â€Å"I Have a Dream† speech addresses the grueling topicRead MoreRhetorical Analysis Of I Have A Dream Speech768 Words   |  4 PagesBrandon Lim CU English 9/29/17 P:2 Using a variety of rhetorical devices, Martin Luther King Jr’s purpose of his â€Å"I Have A Dream Speech† takes a huge step for black americans by voicing the opinions of the people in a civil, non violent manner. He’s a role model for future activists to present the point clearly without hostility or anger, but with a firm tone and many of rhetorical devices. Dr. King gives the speech to help his cause of nonviolent activism against segregation and in favor of civilRead MoreRhetorical Analysis Of I Have A Dream Speech901 Words   |  4 PagesOne of the most acknowledged Civil Rights activists in this history of the United States, Martin Luther King, in his empowering speech, â€Å"I Have a Dream,† proposed his desire for racial equality across the globe in a strong-minded manner. King’s purpose for both writing and orally publishing this speech at the March on Washington affair was to motivate his audience into demanding racial justice and an amalgamated society for all people. He acquired a shameful but dedicated tone as he described theRead MoreRhetorical Analysis Of I Have A Dream Speech1018 Words   |  5 PagesI Have a Dream by Dr. Martin Luther King Jr. Cruelty, inequality, death, sorrow, misery. All words to be associated with the hardships Dr. Martin Luther King Jr. passionately describes in his I Have A Dream speech. King, an activist and civil rights leader gave an empowering speech on August 28, 1963 in Washington D.C. Millions of hearts were touched and inspired to fight for their rights(â€Å"American Rhetoric: Martin Luther King Jr.†). This speech is aimed towards every race in a different specificRead MoreRhetorical Analysis Of I Have A Dream Speech1002 Words   |  5 PagesA Dream Come True Picture yourself living in a society where people are judged and hated upon because of the pigment of their skin, terrible right? Enslaved, criticized, and alienated because there were â€Å"different† from everyone else. Even when granted freedom, colored men and women were still treated as if they were peasants to America. Martin Luther King Jr’s speech had the power to motivate this broken society to end their racist ways. After being lied to for many of years about being â€Å"free†,