1. Conductive arteries – Conductive arteries are the most proximal compartment of the coronary arterial system. Their diameter is generally ranging from 500 μm up to 2-5 mm. These are large epicardial coronary arteries that work as a capacitance function for the blood flow. They have very low resistance to blood flow and therefore, the pressure drop along the length of conductive arteries is negligible. The conductive arteries have an inbuilt characteristic of maintaining the shear stress by changing epicardial dilatation. This characteristic is called being responsive to flow-dependent dilatation. They are not very responsive to intravascular pressure or metabolites. [1]
Prearterioles – Prearterioles are the intermediate compartment to conductive arteries. Their diameter ranges from 100-500 μm approximately. The drop in pressure across the prearterioles is large. They have thick walls and extra-myocardial position due to which they do not come across metabolites and hence do not respond to them. The prearterioles are more responsive to flow-dependent dilation than the conductive arteries. [1]
Arterioles - Arterioles are the most distal compartment of the coronary arterial system with diameters of less than 100 μm. The drop in pressure along the arterioles is considerable and maximum of all the three compartments of coronary arterial system. They are also the most responsive to flow-dependent dilatation during epicardial changes due to varying blood flow. They are responsible for the metabolic regulation of coronary blood flow. This is because they are highly responsive to the changes in the concentration of intramyocardial metabolites. They are also highly more responsive to changes in intravascular pressure than the other comp...
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The cardiovascular system - The cardiovascular system is responsible for transporting nutrients and removing gaseous waste from the body. It consists of the heart, which powers the whole process, the veins, arteries, and capillaries, which deliver oxygen to tissue at the cellular level. The cardiovascular system carries blood that is low in oxygen away from the heart to the lungs via arteries, where oxygen levels are restored through the air once oxygenated, this blood is then carried throughout the body via arteries, keeping our organs and tissue alive. The cardiovascular system is the workhorse of the body, continuously moving to push blood to the cells. If this important system ceases its work, the body dies.
Baroreceptors are sensors in the vascular system that respond to changes in pressure within blood vessels. Baroreceptors are found in the carotid sinus, aorta; the largest artery and the heart’s muscular pumping chamber, and wall of the left ventricle. They monitor the level of arterial pressure and act against in the order to lessen the force in the dilation of blood vessels, which decreases the blood pressure. Chemoreceptors, located in the brain, the two main arteries that carry blood to the head and neck, and aortic body of baroreceptors, are sensitive to changes in concentrations of oxygen, carbon dioxide, and hydrogen ions (Ph) in the blood. A decrease in arterial oxygen concentration or Ph causes a reflexive rise in pressure where an increase in carbon dioxide concentration causes a decrease in blood pressure. Ph is the numeric scale used to identify the basicity and acidity of a solution. Basic is on the top of the scale while acid is on the
The walls of arteries are made up of three layers same as veins. Its inner endothelium is composed of epithelial cells which is very smooth. This layer helps minimise the friction. The tunica media provides strength and elasticity. It contains smooth muscles, collagen and large amount of elastic fibres.
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.
Elaborate: The cardiac cycle of the heart is divided into diastole and systole stages. Diastole refers to the period of relaxation experienced by the atria and ventricles. Systole is the contraction of the atria and ventricles. The pattern of blood flow starts in the left atrium to right atrium then into the left ventricle and right ventricle. During its course, blood flows through the mitral and tricuspid valves. Simultaneously, the right atrium is granted blood from the veins through the superior and inferior vena cava. The job of the superior vena cava is to transport de-oxygenated blood to
The heart serves as a powerful function in the human body through two main jobs. It pumps oxygen-rich blood throughout the body and “blood vessels called coronary arteries that carry oxygenated blood straight into the heart muscle” (Katzenstein and Pinã, 2). There are four chambers and valves inside the heart that “help regulate the flow of blood as it travels through the heart’s chambers and out to the lungs and body” (Katzenstein Pinã, 2). Within the heart there is the upper chamber known as the atrium (atria) and the lower chamber known as the ventricles. “The atrium receive blood from the lu...
Cardiovascular disease is currently the nation’s leading non-communicable cause of morbidity and mortality. According to the American Heart Association, the most common form of cardiovascular disease is coronary artery disease, a condition in which the heart’s blood supply is reduced due to a narrowing of the coronary arteries. These arteries play a significant role in regulating the flow of oxygenated blood to the heart. As blood circulates through the arteries, it exerts a force against the vessel walls, known as blood pressure. To withstand this pressure, elastic fibers interspersed along the artery walls allow the arteries to expand and recoil. Abnormally high blood pressure, however, will cause these muscles to thicken as a result of tears in the damaged artery walls trapping particles that aggregate as plaque. Progressive build-up of plaque ultimately leads to a narrowing of the arteries, subsequently diminishing blood flow to the heart and other body organs. This cascade of events triggered by high blood pressure illustrates why hypertension is one of the most important risk factors for cardiovascular disease. Affecting 1 in every 3 adults in the United States alone, hypertension substantially raises the risk for heart disease in an affected individual who, most likely, does not show any signs or symptoms. In addition to the risks associated with this “silent killer,” comorbidities such as obesity, diabetes, and high cholesterol can drastically worsen health outcomes in hypertensive patients. Given the high prevalence and severe consequences of hypertension if undetected, researching this particular topic will increase our understanding of the causes of hypertension by identifying and narrowing down lead candidates for pot...
The circulatory system and respiratory system share a highly important relationship that is crucial to maintaining the life of an organism. In order for bodily processes to be performed, energy to be created, and homeostasis to be maintained, the exchange of oxygen from the external environment to the intracellular environment is performed by the relationship of these two systems. Starting at the heart, deoxygenated/carbon-dioxide (CO2)-rich blood is moved in through the superior and inferior vena cava into the right atrium, then into the right ventricle when the heart is relaxed. As the heart contracts, the deoxygenated blood is pumped through the pulmonary arteries to capillaries in the lungs. As the organism breathes and intakes oxygenated air, oxygen is exchanged with CO2 in the blood at the capillaries. As the organism breathes out, it expels the CO2 into the external environment. For the blood in the capillaries, it is then moved into pulmonary veins and make
The Circulatory System is a transportation and cooling system for the body. The Red Blood Cells act like billions of little mail men carrying all kinds of things that are needed by the cells, also RBC's carry oxygen and nutrients to the cells. All cells in the body require oxygen to remain alive. Also there is another kind of cells called white blood cells moving in the system. Why blood cells protect from bacteria and other things that are harmful. The Circulatory system contains vein arteries, veins are used to carry blood to the heart and arteries to carry the blood away. The blood inside veins is where most of the oxygen and nutrients are and is called deoxygenated and the color of the blood is dark red. However, blood in the arteries are also full of oxygen but is a bright red. The main components of the circulatory system are the heart, blood, and blood vessels.
The concept between life and death cannot simply exist without one another, where the topic is widely discussed throughout “When Breath Becomes Air” by Paul Kalanithi. This memoir explores Paul’s definition of death as he passes through the distinct “stages” of his life. As Paul progresses through each stage, he views death differently as he transformed from a student to a neurosurgeon, neurosurgeon to a patient, and eventually becoming a father, where he needed to take full responsibility as an adult.
Though shear induced cytosolic calcium was increased in normal endothelial cells, diseased artery and mutant endothelial cells did not show any calcium response to shear stress.[5, 7] To verify cilia function specifically against fluid shear stress, a new technique involving artery perfusion in glass capillary was utilized.[7, 120] And it was observed that though cilia react normally when other mechanical stimuli are applied, response to fluid shear stress is highly altered. In these studies, different inhibitors were used to block molecular functions of cells. When EGTA removes extracellular calcium, both cytosolic calcium and nitric oxide production was eradicated. Then L-NAME (NG-nitro-L-arginine methylester), an eNOS inhibitor, was found to block shear induced nitric oxide synthesis but not cytosolic calcium increase. This proved the necessity of cytosolic calcium for production of nitric oxide but not vice-versa. To examine calcium dependent mechanism of nitric oxide biosysnthesis, calphostin C and W7 were employed.
upright. The backflow of blood is prevented by one-way valves. Superficial veins are linked to the
The arteries supply blood rich in oxygen to the body, the veins direct deoxygenated blood from the capillaries back to the heart. These roles make up the circulatory function. Blood flow through these blood vessels can be disrupted resulting in peripheral vascular diseases. These diseases occur as a result of narrowing or blocking of the blood vessels. The risk factors of peripheral vascular diseases include diabetes, smoking, high level of cholesterol, overweight, high blood pressure etc. these risk factors result to aneurysms, Raynaud’s diseases, Buerger’s disease, renal artery disease etc. With this diseases, the peripheral vascular system should be assessed to enable nurses and other health personnel make good