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Pathophysiology of atherosclerosis essay
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Atherosclerosis is a cardiovascular disease characterized by the deposition of materials such as lipids, cholesterol, and proteins such as fibrins in the arteries, as seen in Figure 1 below. This leads to increased resistance to blood flow and causes the stress on the heart to increase.
The main risk of atherosclerosis is that it greatly increases the probability of blood clots forming in arteries. Should such clots occur in the carotid or coronary arteries, they can result in strokes or myocardial infarctions, which can be fatal2. This paper seeks to analyze how physical principles can be used to elucidate the pathophysiology of atherosclerosis and its effects on the human body.
Physical Principles
Continuity Equation
This equation states that for an incompressible, non-viscous fluid with constant density flowing through a channel, the mass and volume of the fluid are conserved. As a result, the rate of fluid volume flow has to be constant at different points where the cross-sectional area differs.
∆V/∆T=A_1 V_1= A_2 V_2 (1)
With reference to Eq. (1), ∆V/∆T refers to the rate of fluid volume flow, while A refers to the cross-sectional area and V the fluid velocity at points 1 and 2 in a tube respectively. From Eq. (1), it can be seen that as the rate of fluid volume flow is assumed to be constant for an incompressible fluid, a decrease in the cross-sectional area of a tube would lead to an increase in the fluid velocity passing through it3.
Bernoulli’s Equation
Ideally, in the absence of fluid friction, the flow of incompressible fluids can be described by Bernoulli’s Equation:
P_1+ ρgy_1+1/2 ρv_1^(2 )= P_2+ ρgy_2+1/2 ρv_2^(2 ) (2)
With reference to Eq. (...
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...lp to reduce the levels of low-density lipoprotein levels and potentially slow the development of atherosclerotic plaques in blood vessels16. With these advancements in pharmaceuticals, it may be much easier to control the advancement of atherosclerosis in future.
Works Cited
1. Merck - MK-0524B - Treatment of Atherosclerosis. (June 6, 2014); from http://www.pharmaceutical-networking.com/merck-mk-0524b-treatment-of-atherosclerosis/.
2. J. Losos, K. Mason, S. Singer, based on the work of P. Raven, & G. Johnson, Biology, 8th ed., (McGraw-Hill Education (Asia), Singapore, 2008), pp. 994-995.
3. H. Young, & R. Geller, Sears & Zemansky's College Physics, 8th ed., (Pearson Education Inc., San Francisco, 2007), pp. 422-426, 428, 430-431.
4. P. Davidovits, Physics in Biology and Medicine, 3rd ed., (Elsevier Inc., United States of America, 2008), pp. 101-104, 110-112.
They just forgot to mention the other effects of fluids in nature. “The influence of the fluid on a body moving through it depends not only on the body’s velocity but also on the velocity of the fluid,” this is called relative velocity ( ). The relative velocity of a body in a fluid has an effect on the magnitude of the acting forces. For example, as a long distance runner is running into a head wind, the force of the fluid is very strong. If the runner is running with the help of a tail wind, the current’s force is reduced and may even be unnoticeable.
Although atherosclerosis affects millions of people around the world, there are many ways to prevent and treat it once it has developed. Simple life style changes can greatly reduce the inflammation and damage to the endothelial wall of the artery. It is very important that people who have high blood pressure or diabetes get regular checkups; if atherosclerosis goes untreated, the adverse effects, such as stroke or myocardial infarction can be deadly.
Coronary artery disease (CAD) is the most common type of multifactorial chronic heart disease. It is a consequence of plaque buildup in coronary arteries. The arterial blood vessels, which begin out smooth and elastic become narrow and rigid, curtailing blood flow resulting in deprived of oxygen and nutrients to the heart [1].
Coronary heart disease is defined by the hardening of the epicardial coronary arteries. The buildup of plaque in the arteries slowly narrows the coronary artery lumen. In order to better understand the physiology of the disease, it is important to first know the basic anatomy of the human heart. The aorta, located in the superior region of the heart, branches off into two main coronary blood vessels, otherwise known as arteries. The arteries are located on the left and right side of the heart and span its surface. They subsequently branch off into smaller arteries which supply oxygen-rich blood to the entire heart (Texas Heart Institute, 2013). Therefore, the narrowing of these arteries due to plaque buildup significantly impairs blood flow throughout the heart.
Atherosclerosis is the culprit behind coronary heart disease (CHD) and stroke, which is the most common cause of death worldwide and in the United States10. Among the modifiable risk factors of CHD and stroke is the serum low density lipoprotein level (LDL)8, 11. Several randomized clinical trials have established that reducing the serum LDL level results in a reduction in the future risk of CHD and stroke in a linear relationship, in one study it was estimated that reducing the LDL by 1 % would reduce the risk by 1.7 %.1-4, 7, 9, 13
The shear viscosity is a transport coefficient for momentum in inhomogeneous flows. This transport coefficient, which is widely used to describe both plasmas and fluids, relates two hydrodynamic quantities: shear stress and shear rate. The shear stress Pxy is the off-diagonal element of a pressure tensor, and the shear rate γ is the transverse gradient of the flow velocity u. For a flow in the y direction,
Bernoulli’s principle is the concept that as the speed of a moving fluid (liquid or gas) increases, the pressure within that fluid decreases. This principle was originally formulated in 1738 by the Swiss mathematician and physicist Daniel Bernoulli, it states that the total energy in a steadily flowing ...
Consider the parallel flow of two viscous fluids in an infinite, fully saturated, uniform, homogeneous and isotropic two porous media with the Darcy's coefficients and . The statically stable situation was considered, so the upper fluid is assumed the lighter (vapor) while the lower one is assumed to be the heaver (liquid). The two fluids are incompressible and have uniform densities and viscosities for the liquid and for the vapor. The interface between the two fluids is assumed to be well defined and is initially flat to form the plane y = 0. Also, we consider that the two fluids are streaming with uniform horizontal velocities and throughout the two superposed porous media. The subscripts (1) and (2) refer to the lower and upper fluid, respectively. The acceleration due to gravity
The Bernoulli’s equation was mainly derived for ideal fluids i.e zero viscous fluids hence they are frictionless. But all the fluids are real and has some viscosity and hence offer resistance to flow. When the fluid is flowing there will always be some losses across the sections and Bernoulli’s equation considers all the losses.
Viscosity is the tendency of a fluid to resist flow and can be thought of as the internal friction of a fluid. Microscopically, viscosity is related to molecular diffusion and depends on the interactions between molecules or, in complex fluids, larger-scale flow units. The opposite of the viscosity is the fluidity which measures the mobility for fluid layers (Secco et al, 2013). Viscosity is affected by the temperature and composition of the fluid and, for compressible fluid, also by pressure (Serway et al, 2012).
... middle of paper ... ... 14 Nov 2011.. http://web.ebscohost.com/lrc/detail?vid=4&hid=110&sid=fef50b1c-4aba-40fd-83b1- 583a32991f55@sessionmgr110&bdata=JnNpdGU9bHJjLWxpdmU=> Edrich, Matthias. The.
On a more scientific note I am interested in mechanics of fluids. This interest was enforced last year when I had the opportunity to attend a lecture on fluid mechanics at P&G. At the conference I greatly expanded my knowledge regarding the physical aspect of fluids and their properties. In last year's AS course we have met a topic in this field. I will be applying ideas and knowledge gathered from last year for this investigation.
Ibid. 78. -. Ibid. 78. -. Davidson, C., Martin, L., & Wilson, J. (2007).
It can be presumed that the volumetric flow rate will be reduced similarly to the Hagen–Poiseuille equation, due to the laminar flow within the tube in Yeh, H. experiment in 2009, he takes into account convection as well as mass, and momentum balance: