Introduction
If the endothelium were to be considered an organ, it would be without a doubt the largest, with its 6 trillion cells, area of 5000m2, and 1kg weight. With knowledge of the endothelium stemming back to the early 1600s with William Harvey’s work on the circulation as a closed circuit with a pump and Marcello Malpighi’s observations of blood capillaries, the focus over the next 400 years was mainly on the pump itself, leading to the creation of a major clinical field – cardiology. Although scientists were aware of blood vessels and their role in circulation, it wasn’t until the early 1960s that the endothelium was able to be seen with electron microscopy and therefore be differentiated and characterized.1 The recognition of endothelial cells with diverse structures and functions led to an overwhelming increase in research and interest in this field, and it is now well-established that endothelial cells make up a rather active cell layer, and are highly adapted to their microenvironment. In particular, a specific growth factor VEGF has been found to be unquestionably relevant to nearly all endothelial disorders.
Role and Classification of the Endothelium
It is widely known that the endothelium plays a role in nearly every disease state ranging from cancers in hematology-oncology and sepsis in infectious disease to hepatitis and strokes, in gastroenterology and neurology, respectively. Consequently, one cannot rely solely on the mechanisms an endothelial cell from one location as a model and predictor of structure and function of another, as it is recognized that there are a diverse amount of phenotypes, each differing from one another.2 As “endotheliology” is not a recognized clinical discipline, most knowledge conce...
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...y, and more notably, VEGF has been shown to accelerate plaque neovascularisation and progression. However, the use of endothelial cell growth factors and inhibitors for patients with cardiovascular diseases raises some issues. On one hand, VEGF inhibitors are desired to regulate plaque angiogenesis and prevent rupture. However, upon plaque rupture and stenosis of the artery, VEGF therapy can be employed to palliate severe vascular occlusion. In addition, “anti-VEGF” does not equate to “anti-angiogenesis”, as the general effects of stimulators and inhibitors with widespread mechanisms and differences in cell targets cannot be generalized to all agents. Currently, without any tools to monitor plaque neovascularisation or to predict plaque hemorrhage, the risks of promoting plaque angiogenesis, instability and acute ischemic syndromes cannot be accurately estimated.21
Heart (Cardiac Muscle) Cells. Question 1: Briefly describe, in 500 words or less, the normal structure and function of your chosen cell type. In your answer, discuss specific features of your chosen cell type, including cell organelles. Throughout the heart, cardiac muscle cells are connected together to form a large network from one end to the other.
The gaseous free radical nitric oxide is an abundant intracellular messenger molecule that plays a central role in maintenance of health, and is heavily involved in signal transduction in various cells of the body [1]. This molecule acts as a mediator in the regulation of cardiac function as well as having an important role in regulating contractility of the heart and maintenance of vascular tone in the cardiovascular system. As one of the most significant individuals in our discovery of nitric oxide, Dr. Robert Furchgott pioneered our understanding of this molecule through his experiments on the vasorelaxant properties of acetylcholine and the subsequent proposal of the presence of the endothelium derived relaxing factor, which was later identified to be nitric oxide [7]. Given the observation that cardiovascular disorders are the number one cause of death in many nations around the world, research into the vasorelaxant properties seems particularly relevant in order to help combat rising rates of vascular hypertension and high blood pressure. In this paper, the properties of nitric oxide are discussed largely with respect to the cardiovascular system. This paper focuses on the synthesis and characteristics of nitric oxide, the mechanisms of action by which nitric oxide works and the regulation of nitric oxide in the body, and finally a short summary of Robert Furchgott’s contributions to the discovery of nitric oxide and its properties.
In 1615 at the age of 37 Harvey became the Lumleian Lecture specializing in Surgery. William Harvey discovered his finding of the Circulation of Blood by ignoring medical textbooks and dissecting animals. He gained all or most of his learnings from observations of cutting open veins and arteries of living animals. Many people of this modern time thought because there weren’t any anesthetics that Harvey was cruel for cutting open living animals. I think that if it wasn’t for William Harvey and all of his studies and dissections that we wouldn’t be able to learn teach and save as many people as we can today. We as people have learned a lot from the many studies and dissections throughout Harvey’s lifetime. We have learned that blood, arteries, and veins are all within the same origin, blood in the arteries sent to the tissues are not stay there, the body‘s circulation mechanism was designed for the movement of liquid and that blood carrying air is still blood, the heart moves all movements of blood not the liver, hearts contract the same time as the pulse is felt, ventricle’s squeeze blood into main arteries, the pulse is formed by blood being pushed into arteries making them bigger, there are no vessels in the heart’s septum, lastly there is no to in from of blood in the veins there is only
Barlic J, & Murphy PM. (2007). Chemokine regulation of atherosclerosis. Journal of Leukocyte Biology. 82, 226-36.
The science and history of the heart can be traced back as far as the fourth century B.C. Greek philosopher, Aristotle, declared the heart to be the most vital organ in the body based on observations of chick embryos. In the second century A.D, similar ideas were later reestablished in a piece written by Galen called On the Usefulness of the Parts of the Body. Galen’s thesis was that the heart was the source of the body’s essential heat and most closely related to the soul. Galen made careful observations of the physical properties of the heart as well. He said “The heart is a hard flesh, not easily injured. In hardness, tension, in general strength, and resistance to injury, the fibers of the heart far surpasses all others, for no other instrument performs such continues, hard work as the heart”(Galen, Volume 1).
Cardiovascular Diseases (CVD) are the currently the leading cause of death globally for both men and women accounting for 21.9 per cent of total deaths and is projected to increase to 26.3 per cent by 2030 . Statins are the treatment of choice for the primary and secondary prevention of cardiovascular disease and in the management of hypercholesterolaemia because of their proven efficacy and safety profile. Evidences are showing their effectiveness in reduction of cholesterol synthesis and number of pleiotropic effects, which may be cholesterol dependent and cholesterol independent. The present review focus on the origin, properties and effects of statins on endothelial function ( non lipid action of statins) through the increase of endogenous production of NO in different pathways.
The term, ischemia, denotes inadequate blood supply to tissues due to blockage of the arterial inflow, while, reperfusion injury is defined as the injury caused by the restitution of blood flow after an ischemic peroid, leading to death of cells that were only reversibly injured at the time of blood flow restitution. [63]. The final infarct size after an MI event is therefore the result of the ischemic and reperfusion damage. For this reason, the term that best describes this process of myocyte death in reperfused MI is myocardial ischemia/reperfusion (I/R) injury [64]. In the early hours post myocardial ischemia, injured cardiac cells can release several molecules, including adenosine, opioids, and bradykinin, which activate the G protein signaling pathways therefore promoting myocardial survival. While in the late phase, myocardial ischemia induces upregulation of growth factors and cytokines, including VEGF, ILGF and SDF-1, in the injured myocardium, hence promoting a cardio-protective state. The liver also participates in cardioprotection through the up regulation and release of secretory proteins, including FGF21 and TFF3, which also promote cardiomyocyte survival. [65]. Foundational studies performed about three decades ago with animal models demonstrated that an early reperfusion was able to limit infarct size [66]. Then fibrinolysis was indisputably associated with a decrease in mortality in patients with STEMI [67].A decade later; primary angioplasty was shown to be more superior than fibrinolysis [68]. Currently primary coronary angioplasty (PCI) has been established as the backbone treatment for STEMI patients. The period from the onset of symptoms of MI (representative of the time of coronary occlusion) and reperfusio...
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...
Artherosclerosis is characterized by fatty deposits that develop as streaks inside the lining of arteries and some streaking can be found in teenagers and then by an increasing proportion of the population from then on. If you were to ask the experts what causes arteriosclerosis the answer would depend on the expert. Researchers do not agree on the causation but they have agreed on possible risk factors such as smoking, a high fat diet, high cholesterol levels, high blood pressure, high iron levels, inflammation and bad genes. None of which appear to be the primary cause because if you were to eliminate one possible cause you should eliminate the disease. Many researchers have begun to think that many diseases including cancers originate as a composite of risk factors and that approach does not make sense because it suggests that Human arteries are so fragile that any one or combination of the...
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 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.
Press, 1967. Lubitz, Steven. A. A. “Early Reactions to Harvey's Circulation Theory: The Impact on Medicine.” Mount Sinai Journal of Medicine 71 Issue 4 (2004): 274.
Bacteria exist everywhere in the environment and have continuous access to the body through the mouth, nose and pores of skin. Further more, many cells age and die daily and their remains must be removed, this is where the white blood cell plays its role.
The blood that is being carried away is very enriched with oxygen after it leaves the lungs and proceeds to the body’s tissues. The further the arteries get away from the heart they become smaller and more narrow and are eventually called arterioles. Arterioles and arteries just about have the same structure and function. Arterioles have strong, thick muscular walls and a rather small passageway for the blood to travel in and out. Also, they are the most highly regulated blood vessels in the blood and contain blood under high blood
Every organ in the human body is composed of one or more tissues. The study of these tissues is known as histology. It is because of histology that the structure of organs can be researched and understood. Since organs are composed of tissues, it is important to understand each tissue type, their structure, their location, and their functions to better understand how each organ operates within the human body.