Explaining The Pumping Action In A Heart Physical Education Essay

Explaining The Pumping Action In A Heart Physical Education Essay The heart is the most important organ of the blood which keeps the other internal organs alive by supplying blood and oxygen hence making it a life maintaining organ. The objective of this essay is to explain the pumping action of the heart, transportation of oxygen by the cardiovascular system and how reduced blood flow can affect cardiac function. A treatment for this cardiac malfunctioning is also explained. I will begin the essay by explaining the anatomical structure of the heart and then explain how the pumping action of the heart. The second part of the essay will include how the reduction in blood flow can affect the cardiac function and finally a treatment to cure this problem will be explained. The heart is a life maintaining organ weighs almost less then a pound, barely the size of the fist and located in the mediastinum of the throracic cavity of human body. The shape of the heart is like a inverted cone which has a blunt tapered end that points to the left hip and the base pointing towards the right shoulder. The heart lies more close to the left that is nearly third of it and rest on the diaphragm in between the two lungs. This is shown in figure 1 which shows the location of the heart. Fig.1: Anterior view of the heart in the mediastinum The entire heart is covered by a dense fibrous tissue called the pericardium which comprises of a dense connective tissue called the fibrous pericardium which protects the heart from over stretching due to excessive filling, it also consists of the serous pericardium which forms deeper portion of the heart. The serous layer is further divided into the parietal layer which lines the outer layers the and visceral layer which lines the innermost layers of the heart. A fluid which reduces friction is present in the pericardial cavity that separates these parietal and visceral layers. The below figure (see fig. 2 ) shows the different layers of the the pericardium. Fig.2: The pericardium and the Heart wall http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cardiopart=A1016rendertype=figureid=A1019 As shown in the above figure (see fig.2), the heart wall is composed of three different layers ; epicardium, myocardium and the endocardium. The epicardium which forms superficial layer of the heart wall consists of mainly adipose tissue. The endocardium forms the deeper layer of the heart and is filled with squamous endothelium and aerolar tissues. Between these two layers lies the myocardium which is made up of cardiac muscles that help in the contraction of the heart. Its relatively a thick layer as it helps the heart to perform its normal pumping action that is contraction and expansion of the heart at regular intervals. On the outer surface of the heart there many grooves and layers of fat called the sulci. The heart is divided into four chambers which has two inferior intermittent pumps which discharge blood out of the heart called the right and the left ventricles and two superior primer pumps called the right and left atria receiving deoxygenated and oxygenated blood from the body and the lungs respectively. The ventricles are separated from each other by a relatively thick muscle called the interventricular septum but atria are separated from each other by relatively a thinner wall called the interatrial septum as it has lighter workload comparing the ventricles. The right ventricle has thicker walls comparing the left ventricle because it has to pump more blood during systemic circulation. The presence of heart valves prevents the back flow blood and hence ensures that blood flows effectively in one direction. There are two types of valves which are the atrioventricular (AV) valves and the semilunar valves. The AV valves consists of the the tricuspid and bicuspid (mitral) valves th at are located on the right and left side of the heart between the ventricles and atria respectively. The semilunar valves on the other hand lie on the bases of aorta and the pulmonary artery. These valves consists of the pulmonary valve and the aortic valve. The tricuspid valve has thread like structures that are connected to tendon like cords called the chordae tendinae. The anatomical structure of the heart and the heart valves is shown in figure 3. Fig.3: The heart and the heart valves http://yoursurgery.com/ProcedureDetails.cfm?BR=3Proc=24 Blood Flow Through The Heart The blood flow through the heart is explained by the pulmonary and systemic circulation. Deoxygenated blood is drained into the right atrium by the superior and the inferior vena cava. The pressure in the right atrium increases forcing the tricuspid valve to open and hence draining the entire deoxygenated blood to the right ventricle. The volume of blood in the ventricle increases and the maximum volume of the blood in the right ventricle after the contraction of the right atrium is called end diastolic volume (EDV). EDV is generally about 140ml. As the tricuspid valve closes the pressure in the ventricles increases. During this phase the ventricles contract but the pressure is not enough for the pulmonary valve to open hence resulting in isometric contraction as a result all the heart valves are closed during this phase and the volume in the ventricles remains constant. As the pressure continues to increase comparing the right atrium the blood forces open the pulmonary valve and the deoxygenated blood is pushed into the pulmonary trunk that divides into the pulmonary arteries. After the contraction of the ventricle that is the systole, the amount of blood remaining in the ventricle is called the end systolic volume (ESV). The difference between EDV and ESV gives the stroke volume (SV) that is the blood pumped out of the ventricles during a single heart beat. The pulmonary arteries carries the deoxygenated blood to the right and the left lung for oxygenation. Once the blood is oxygenated it is returned back to the heart by the pulmonary vein. The pulmonary vein empties the oxygenated blood into the left atrium, hence completing the pulmonary circulation and as the pressure in this atrium increases the blood is drained into the left ventricle by forcing open the mitral valve. When the mitral valve is closed the the pressure rises again comparing the left atrium and the blood is pushed into the aorta by opening the aortic valve. This oxygenated blood is transport ed to various parts of the body to carry out haemodynamic activities ( which includes the exchange of oxygen and carbondioxide with the blood ) . The systemic circulation is completed once the deoxygenated blood is returned back to the right atrium from different parts of the body by the venae caveae. Fig.4: Pulmonary and Systemic Circulation of the heart http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f22-1_cardiovascular_sy_c.jpg During the phase of the first diastole, the ventricular relaxation takes place as a result the semilunar valves are closed and also the AV valves are also closed during this time as a result the volume of blood in the ventricles remains constant, hence this phase is called the isovolumetric relaxation. The diagrammatic explanation of the cardiac cycle is explained in figure 5. Fig.5: The Cardiac Cycle http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f22-11_cardiac_cycle_c.jpg Cardiac Conduction System In this system the pumping action of the heart is synchronised by the electrical activity of the heart. Electrical signals are generated by the sinoatrial (SA) node which is the bodies natural pacemaker. This node generates pulses that propagate throughout the right atrium and through the Bachmanns bundle hence stimulating both the atria. These pulses travel from SA node the to the atrioventricular (AV) node through certain paths known as internodal tracts. The AV node acts as a gatekeeper and prevents all the pulses to travel from the atria to the ventricles, hence causing some delay in the excitation. From the AV node the signals travel through the Purkinje fibres that divides itself into right and left and excites both the ventricles. This process repeats and the contraction of the heart takes place. Transportation of Oxygen by Cardiovascular System The cardiovascular system is a dense network of arteries, veins, capillaries etc. which is involved in the transportation of blood gases to and from the various parts of the body. In this part I will talking about how the cardiovascular system transports oxygen to different parts of the body. The oxygenated blood which is pumped from the left ventricle is transported by the aorta. The aorta is the largest artery of the human body which is made up of several layers of the elastin fibers and covered by smooth muscle. Blood flows in the arteries with high pressures hence these arteries expand (vasodilation) and contract (vasoconstriction) thus helping to regulate blood pressure. The aorta bifurcates into various different arteries smaller in size carrying oxygenated blood to different parts of the body. These arteries further divide into arterioles whose diameter is much smaller comparing the arteries and are less elastic. These arterioles are made up of thick layer of smooth muscles an d are controlled by the autonomic nervous system that control their diameter. Oxygenated blood now passes from the arterioles to the capillaries which are the functional unit of the cardiovascular system. Capillaries are responsible for the exchange of blood gases and other nutrients between different tissues and blood through the process of diffusion. As diffusion is the process by which gases or fluids flow from higher to lower concentration therefore at the capillary level the concentration of oxygen is more in the capillaries and on the other hand the concentration of carbondioxide is more in the tissue than in the capillaries therefore the diffusion of these gases takes place. Oxygen is diffused into the tissues and carbondioxide on the other hand is diffused into the tissues. This is how oxygen is transported to different parts of the body. This deoxygenated blood is collected from the venules which are connected to the capillaries. Theses venules group together to form veins. Hence this deoxygenated blood is returned back to the heart for oxygenation and the entire process is repeated. The entire process of the transportation of oxygen by the cardiovascular system is explained in figure 6 Fig 6: Blood flow and capillary exchange of oxygen http://www.patient.co.uk/health/Blood-General-Overview.htm Effects Of Reduced Coronary Blood Flow And Its Treatment Reduced coronary blood flow results in a condition known as ischemia where the myocardiac tissue is deprived of oxygen due to inadequate blood flow. The inadequacy is caused by formation of localised plaques of lipids that protrude within the artery causing a reduction in blood flow. As a result of reduced blood flow, there is a reduction in the level of oxygen which is required to carry out metabolic activities of the tissues. In ischemia the anaerobic respiration of the tissue results in the formation of lactic acid which leads to sever pain in the chest region. This pain is called angina pectoris. Angina pectoris is classified into two types; stable and unstable. Stable angina which causes pain in the chest region may arise from some physical activity ( running, jogging etc.). During these activities the need for oxygen is more to carry out metabolic activities in a faster rate compared to the supply of oxygen as a result anaerobic respiration of the tissues takes place and hence results in the formation of lactic acids which causes this pain. In unstable angina there is a persistent pain in the chest regions this is because of the accumulation of platelets on the ruptured plaques which leads to the blockage of the arteries and hence causing immense reduction in blood flow. Persistent unstable angina may cause myocardial infraction which ultimately may lead to sudden death. There are many ways to treat angina it may be either surgical or non surgical ways. Surgical methods include coronary balloon angioplasty where a catheter is passed into an artery with a balloon at the tip of the catheter. The balloon is made to expand causing the artery to expand and hence breaking of the plaque of lipids in the artery. Another types of surgical method is the coronary bypass surgery where the blocked artery is completely removed and replaced with a new one taken from different parts of the body. Non surgical methods include taking drugs that cause vasodilation such as ni troglycerin which converts into nitric oxide and hence dilates the coronary artery causing an increase in blood flow. Beta adrenergic blocking receptors are used to reduce the heart rate and therefore causing a reduction in cardiac output. Other techniques that involve the use of calcium channel blockers that are used for vasodilation and hence helping the flow of blood. Conclusion The heart is a an electromechanical pump which carries out its action through pulmonary and systemic circulation. The pumping action is well synchronised such that there is proper blood flow within the heart and outside to carry out haemodynamic activities. The transportation of blood is carried by a system consisting various networks that are spread throughout the body known as the cardiovascular system. This system helps in the transportation of oxygen to different tissues in order to carry out different metabolic activities. The exchange of oxygen between tissues and the cardiovascular system takes place through a process called diffusion. The effects of reduced blood are many and can lead to a condition known as ischemia. Angina pectoris is one of the main problems that can cause due to reduced blood flow and hence causing a sever pain in the chest region and on sever reduction in blood flow it may even lead to myocardial infraction which ultimately leads to death. There are nume rous treatments for curing this particular problem, it may be either through surgical methods which includes cardiopulmonary bypass and angioplasty or using drugs that increase vasodilation and decrease cardiac output. These drugs include beta receptors, calcium channel blockers and nitroglycerin.

Congo

A component in the development in Operation â€Å"Save the Congo' that we will focus lies in the Health infrastructure. The Democratic Republic of Congo was one of the first African countries to recognize HIV, registering cases as early as 1983. The most common method of transferring the virus occurs through homosexual activity; linking to over 87% cases in the Congo. Demographically, the ages groups most affected are women aged 20 to about 29 and men alike aged 30 to 39.Other method that contribute to the rampant spread of the virus are the large movement of refugees nd soldiers; seeing as though population movements are often associated with the exacerbation of the HIV virus as it is now localized in areas most populated by troops and in other war-displaced populations. In addition, there is the increased levels of sexual transmitted diseases among sex workers and clientele alike, due to the limited availability of condoms in the country.All in all, without the relief of Operation â€Å"Save the Congo' the continuing problem of HIV/AIDS in the Democratic Republic of Congo becomes a leading issue in a country already suffering from other health issues. Along with the spread of the HIV virus, the impact that malaria has on the Democratic Republic of Congo is profound, and this is due to the expansion by insects and the fact that malaria is the primary cause of mortality among pregnant women and young children. On average, there are five million cases of malaria every year in the Congo and around 500,000 to one million people die of this disease every year.In addition, 97% of the countrys 70 million inhabitants live in areas where malaria is deeply concentrated, subjecting most of inhabitants with the vicious disease. Mosquitoes are the primary carriers of malaria, and due to the fact that Congo is located close to the equator, one can assume that the high number of mosquito presence is chiefly due to the humid climate of the country. Along with the expansion of the malaria disease, there are its impacts on pregnant women and children. Of the people that die from malaria, 91% of those inhabitants are ones that are pregnant women or children under the age of five.Children bear the majority of the burden of both the morbidity and mortality, as they are at greater risk of catching he disease and dying as well. Out of the 5 million reported cases of malaria, around 2. 3 million cases of children under five with malaria were reported; with around 25,000 of the 2. 3 million dying from malaria- related diseases. Another section of the health infrastructure we would like to focus on in our relief plan lies in the topic of maternal and child health care.In other words, aside from the malaria epidemic there are other health factors needed to be taken into consideration when discussing maternal and child health care. Due to the lack of resources in the Congo, women nd their children have continuous struggles in sustaining their resources, and thus, taking proper care of their children. The lack of clean water and liveable homes attribute to the dismal health of women and their families, and this only makes them more susceptible to the rampant diseases described previously.According to the United Nations Population Fund released in June 2011, maternal mortality rate for the Democratic Republic of the Congo per 100,000 is 670 deaths. Meaning, that for every 100,000 childbearing woman in the Congo, there are 670 infant deaths. Compared of ther developing countries, that ranks in the top percentile as tar as maternal mortality rates, and that fgure alone only begins to outline the profound impact the weak health infrastructure and the lasting impacts it has on women and children in the country.Despite the daily turmoil men, women and children face everyday in the Democratic Republic of Congo, there is hope. With the implementation of Operation: Save The Congo, we can finally provide the needed relief efforts that was never before applied to the country. Similar to the New Deal used in the United States uring the Great Depression, these programs are meant to relief and reform the Congo into a livable society, and get it to a point where it may function and prosper on its own.In order to achieve this landmark reform in the health sector, Operation: Save the Congo will first build new hospitals. The lack of stable, sanitary hospitals is an on-going problem that continues in the Congo, but with the relief that Operation STC provides, funding will go into building hospitals, helping solve the problems of HIV/AIDS and malaria. In addition, new hospitals will help decrease the maternal ortality rates, as we will provide new technologies needed to prevent disease and malnutrition.Moreover, we want to do a â€Å"reverse brain-drain† method in which we partner will developed countries and send highly skilled doctors, physicians, and nurses over to the Congo to work in these hospitals and provide expert health care. A big part of the new health infrastructure will be the development of a new filtration system to produce clean water not only for newly built hospitals, but for the country in total. This project will be the top priority in guiding the Congo into a new era in ealth technology, as the production of clean water will diminish mortality rates, and it will also help prevent other diseases.Lastly there is the building of living shelters across the country, providing imported foods and goods from developed countries in an effort to sustain lives. This will give the necessary shelter women, men and children need in order to live their lives fully. Bringing in imported foods and goods would also contribute to the decline of diseases, as it gives its inhabitants the proper nutrients from the foods and the quality living standards from the newly imported goods. All in all, these are the problems that persists in the health sector of the Democratic Republic of Congo.HIV/AID, malaria, lac k of resources are all continuous strains on this developing country and its people are fading fast. The programs that were Just highlighted will save the congo, as it will provide newly built facilities including hospital and living shelters with trained practitioners and a new clean water filtration system. With these programs set in place, the health infrastructure in the Democratic Republic of Congo will be on course on becoming a great leader for health in the world.

How Rational Choice Theory Influences Human Behavior

Economics plays a huge role in human behavior. That is, people are often motivated by money and the possibility of making a profit, calculating the likely costs and benefits of any action before deciding what to do. This way of thinking is called rational choice theory. Rational choice theory was pioneered by sociologist George Homans, who in 1961 laid the basic framework for exchange theory, which he grounded in hypotheses  drawn from behavioral psychology. During the 1960s and 1970s, other theorists (Blau, Coleman, and Cook) extended and enlarged his framework and helped to develop a more formal model of rational choice. Over the years, rational choice theorists have become increasingly mathematical. Even ​Marxists  have come to see rational choice theory as the basis of a Marxist theory of class and exploitation.​​​ Human Actions Are Calculated and Individualistic Economic theories look at the ways in which the production, distribution, and consumption of goods and services are organized through money. Rational choice theorists have argued that the same general principles can be used to understand human interactions where time, information, approval, and prestige are the resources being exchanged. According to this theory, individuals are motivated by their personal wants and goals and are driven by personal desires. Since it is not possible for individuals to attain all of the various things that they want, they must make choices related to both their goals and the means for attaining those goals. Individuals must anticipate the outcomes of alternative courses of action and calculate which action will be best for them. In the end, rational individuals choose the course of action that is likely to give them the greatest satisfaction. One key element in rational choice theory is the belief that all action is fundamentally â€Å"rational† in character. This distinguishes it from other forms of theory because it denies the existence of any kind of action other than purely rational and calculative actions. It argues that all social action can be seen as rationally motivated, however much it may appear to be irrational. Also central to all forms of rational choice theory is the assumption that complex social phenomena can be explained in terms of the individual actions that lead to that phenomena. This is called methodological individualism, which holds that the elementary unit of social life is individual human action. Thus, if we want to explain social change and social institutions, we simply need to show how they arise as the result of individual action and interactions. Critiques of Rational Choice Theory Critics have argued that there are several problems with rational choice theory. The first problem with the theory has to do with explaining collective action. That is if individuals simply base their actions on calculations of personal profit, why would they ever choose to do something that will benefit others more than themselves? Rational choice theory does address behaviors that are selfless, altruistic, or philanthropic. Related to the first problem just discussed, the second problem with rational choice theory, according to its critics, has to do with social norms. This theory does not explain why some people seem to accept and follow social norms of behavior that lead them to act in selfless ways or to feel a sense of obligation that overrides their self-interest. The third argument against rational choice theory is that it is too individualistic. According to critics of individualistic theories, they fail to explain and take proper account of the existence of larger social structures. That is, there must be social structures that cannot be reduced to the actions of individuals and therefore have to be explained in different terms.

The Assessment Process Of The Early Childhood Classroom

Module 1 Assessments Explain the Assessment process as used in the early childhood classroom The assessment process in the classroom can be completed in several different ways, but they are effective in helping children. Some steps may include observations, testing, and evaluations. These assessments can help the caregivers provide the children with the best care possible and available for them. These observations and test may be completed from several sources and situations to ensure the test are accurate. Compare and contrast â€Å"traditional assessment† and â€Å"authentic assessment† giving several examples of each. When talking about traditional assessment and authentic assessment there are ways they can be expressed as being different. Authentic assessment is ongoing and applies to all areas in the school or childcare setting. These are practical and express intellectual challenges. This can be completed by matching games, puzzles, and identifying objects. Caregivers and teachers must observe and keep track of the child’s progress to ensure they are meeting their goals. This is another task a teacher must perform on top of teaching. Traditional assessment emphasizes uniform and rote testing. In traditional settings the child’s behavior is looked at in group settings not just a one on one forum. Things are looked at from a group stand point for examples are the children sharing, interacting with others, and feeling like they belong in a group and not just one individual.Show MoreRelatedEarly Childhood Curriculum Planning Essay examples716 Words   |  3 Pagespurpose of curriculu m in the early childhood classroom. Discussed will be the definition of an integrated curriculum, and the connection between curriculum and development in the pre-kindergarten and Kindergarten student. The core content areas of childhood development will be outlined and defined and developmental support provided to all areas of content will be examined. 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