Cardiovascular Disease essays
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Abstract
The heart is a vital muscle organ with autonomous and rhythmical contractions that pumps blood through an extensive blood vessel network distributed all over the body. The heart comprises the myocardium and the endocardium. The heart cavity is structured into four chambers; two ventricles and two atria, separated by cardiac valves regulating blood passage. The pericardium protects and shields the heart from over expanding and anchors it within the thorax, and attaches to the diaphragm and inner surface of the sternum. The pericardium components include the fibrous pericardium, the epicardium or the serous pericardium, and a serous fluid film. Cardiovascular disease results mainly from atherosclerosis and the amplified risk of blood clots, and the damage to arteries. However, the precise cause is unknown though several aspects contribute to the increased risk of acquiring it, including hypertension, smoking, high cholesterol, diabetes, lack of regular exercise, obesity or overweight, history of heart disease in the family. The majority of prevention measures for cardiovascular health are habitual. For instance, stop smoking, the consumption of a balanced diet, and regular exercise. Medical prescriptions aid in managing blood cholesterol, preventing blood clots, and controlling blood pressure. Medical surgery is recommended for specific heart disease and the damage extent. The symptoms of heart disease include chest pain, heart attack, heart failure, a drooping face or eye, inability to smile, immobile arm due to numbness or weakness, and slurred or complete loss of speech, the cramping or dull leg pain that worsens while walking and eases at rest, loss of leg and feet hair, weakness and numbness in the legs, and persistent ulcers on the legs and feet. Aortic diseases have no symptoms but can cause the aorta to burst and initiate life-threatening bleeding.
Keywords: Heart, Blood Vessel, Symptoms, Cardiovascular disease, Blood
Cardiovascular Diseases
Cardiovascular diseases remain to be the major cause of demise globally. According to the WHO, in 2008, over seventeen million persons died from cardiovascular diseases, with over three million demises under the age of sixty. The premature death percentage from CVDs varies from four percent in developed nations to forty-two in low-income states. Cardiovascular diseases are significantly preventable. Henceforth, the paper addresses the physiology and anatomy of the heart and the causes, symptoms, and prevention and treatment of cardiovascular diseases.
Discuss the Physiology and Anatomy of the Heart.
The heart is a vital organ in the cardiovascular system. The heart is a muscle with autonomous and rhythmical contractions, working collaboratively with an extensive blood vessel network distributed all over the body. The heart’s weight is about 350g and measures the size of a clenched fist of an adult. The heart comprises the myocardium, a middle muscular layer developed of cardiac muscle cells, and the endocardium, which is the inner lining. The heart cavity is structured into four chambers; two ventricles and two atria separated by cardiac valves responsible for the regulation of blood passage. The pericardium, a sac enclosure for the heart, protects and shields the heart from over-expanding while at the same time anchoring it within the thorax. Also, the pericardium attaches to the diaphragm and inner surface of the sternum. The components that constitute the pericardium includes the fibrous pericardium, which is a dense connective tissue layer that is loosely fit, the epicardium or the serous pericardium made up of visceral and parietal layers, and lastly, a serous fluid film between the serous and fibrous pericardium that enables them to glide smoothly alongside each other.
Ventricles and Atria
Blood returning to the heart is received in the atria, whereas the blood from the atria enters the ventricle through the atrioventricular valves, after which the ventricles pump the blood to the rest of the body and into the lungs. The right atrium (RA) and ventricle (RV) are separated from the left atrium (LA) and ventricle (LV) by a tissue band, the septum. The superior and inferior vena cava bring deoxygenated blood into the RA from the neck and head and the rest of the body correspondingly. Then, the RV pumps the deoxygenated blood into the lungs for oxygenation via the pulmonary trunk dividing into the left and right pulmonary arteries. The LA receives the oxygenated blood through the pulmonary veins and pumps it into the LV via the cardiac valves. The LV then pumps the oxygenated blood to the rest of the body via the aorta. Importantly, the LV has a thick wall and circular cavity that enable it to pump blood over a longer distance to the rest of the body compared to the RV whose walls are thinner and a crescent-shaped cavity sufficient to pump blood over the shorter distance to the lungs.
The Cardiac Valves
In proper working order, the cardiac valves allow for a one-direction blood flow system. The cardiac valves possess cusps held in position by strong chordae tendinae attached by small papillary muscles to the heart’s inner walls. The tricuspid valve having three leaflets separates the RV and RA and allows for the movement of the deoxygenated blood from the RA to the RV. After that, the deoxygenated blood from the RV passes through the pulmonary valve into the pulmonary artery to the lungs. The oxygenated blood from the lungs is received on the left side of the heart, where it enters from the pulmonary vein into the LA. The mitral or bicuspid valve possessing two leaflets separates the LA from the LV. The oxygenated blood flows into the LV via the bicuspid valve, pumped, and transported to the rest of the body via the aorta.
Coronary Circulation
The heart’s demand for the supply of the rich oxygenated blood is delivered through the left and right coronary arteries, situated on the epicardium, and infiltrate the myocardium with extensive branches. The left and right pulmonary arteries arise from the coronary ostia, which are vascular openings found at the aorta’s base. The left coronary artery supplies the left side of the heart and divides into the left circumflex artery and anterior descending artery. The right coronary artery supplies the right side of the heart and divides into the marginal artery and the posterior descending artery. The coronary arteries facilitate intermittent blood supply to the heart, mainly during diastole, as the coronary arteries entrance is opened at this instance of the cardiac cycle. The heart’s venous drainage system engages the coronary veins that align a similar course as the coronary arteries. The coronary sinus, a coronary veins collection, drains at the posterior of heart into the RA. Nearly two-thirds of the cardiac venous blood is returned through the coronary sinus, whereas a third is taken directly to the heart.
The Heart Rhythm and Conduction System
The cardiac muscle possesses the capacity to depolarize that initiate muscle cells contraction. The sinoatrial node (SAN) generates a sequence of excitation that causes electrical alterations that produce cardiac impulses. The sinoatrial node, found in the right atrium, is the natural pacemaker for the heart, and when properly functioning, it sets the sinus rhythm that affects the myocardium, inducing cardiac contraction. The cardiac impulses pass on to the atria that begin to contract and transmits the impulse to the atrioventricular node (AVN). The AVN is located within the interatrial septum, a tissue band between the LA and RA that avails a conduction pathway amid the ventricles and atria. Due to the smaller fibers of the AVN, the atria have time to contract and pump blood into the ventricles before ventricular contractions occur. The impulse travels down to the “Bundle of His,” which subsequently divides into the left and right bundles within the inter-ventricular septum.
Cardiac Cycle
The heart chambers contract and relax in a coordinated manner referred to as systole and diastole, respectively. There is a synchronization between the RA and LA atrial systole and diastole while the LV and RV synchronize in the ventricular diastole and systole, with the complete cycle addressed as the cardiac cycle. In the cardiac cycle, the cardiac chamber pressure rises and falls, influencing valve closure, and opening. Equal blood volume is pumped per cardiac beat even though the heart’s left side pressure is around five times more than the right side.
During the atrial systole and ventricular filling, the heart pressure is low, forcing the blood from circulation to fill both atria passively. Consequentially, the atrioventricular valves open and blood moves into the ventricles. The atria’s depolarization causes their contraction and, thus, blood compression in the atrial chambers, pumping blood into the ventricles. This forms the last ventricular diastole and the end-diastolic volume (EDV). The atria relax, and the electrical impulse transferred to the ventricles that undergo depolarization.
In ventricular systole, the atria relax while the ventricles contract is causing an increase in ventricular cavity pressure. As the pressure exceeds that in the artery, the aortic and pulmonary valves are forced open, and the blood pumped into the vessels. At this instance, the ventricles relax with any blood residues in the chambers denoted as end-systolic volume (ESV). With the drop in ventricular pressure, blood within the pulmonary trunk and aorta backflows momentarily, and the pulmonary and aortic valves close. The backflow causes a dicrotic notch. With the ventricles in systole, the atria enter diastole and fill again, preparing for the continued cardiac cycle.
Cardiovascular Disease Causes
Cardiovascular disease arises mainly due to atherosclerosis, the build-up of fat deposits within the arteries, and the increased risk of blood clots. Also, the damage to arteries within organs, including the eyes, kidneys, brain, and heart, can develop cardiovascular disease. Nonetheless, there precise cause of cardiovascular disease is not specific though several aspects can contribute to one’s increased risk of acquiring it. One risk factor is high blood pressure or hypertension. When one experiences blood pressure that is too high, they are exposed to increased risk of damaged blood vessels. Notably, high blood pressure can be genetic or can develop due to dietary habits. Another risk factor for cardiovascular disease is smoking. Smoke exposure, both as a tobacco smoker or a passive smoker, can cause damages and narrow the blood vessels, thereby increasing the risk of cardiovascular disease such as stroke. Besides, high cholesterol heightens the risks of experiencing cardiovascular disease. Cholesterol, a fatty matter found in the blood, can cause the constriction of blood vessels, particularly the artery, and the development of a blood clot. Cholesterol levels in the body increase mainly based on dietary habits, especially with the increased consumption of foods rich in saturated fats.
Furthermore, diabetes is known to increase the risk of experiencing cardiovascular disease. Diabetes causes blood sugar levels to rise above normal levels, which can damage the blood vessels and make them narrow. Moreover, several individuals with type 2 diabetes are either obese or overweight, which are risk factors for cardiovascular heart disease. The lack of regular exercise enhances the prospects of acquiring cardiovascular disease. Inactivity leads to high blood pressure, becoming overweight, and high cholesterol amounts, which are all influencers of heart disease.
Moreover, becoming obese or overweight increases, one’s risk of developing high blood pressure and diabetes that are risk factors for cardiovascular disease. A person with a BMI that is twenty-five and above are significantly at risk of heart disease. Importantly, one is at risk of cardiovascular disease if there is a history of heart disease in their family. A family history of heart health is considered for individuals whose father or brother were confirmed cardiovascular disease before fifty-five years or sixty-five years for the mother or sister. Other risk factors for heart disease comprise; age, common among individuals above fifty years, and risks increase with age increase, gender; men are significantly more at risk than women, and excessive alcohol consumption increases blood pressure levels, cholesterol, and weight gain.
Prevention and Treatment of Cardiovascular Disease.
The majority of prevention measures for cardiovascular health are habitual. For instance, it is recommended to stop smoking. With the assistance of one’s general practitioner, it is easy to quit smoking, which also can be done through prescribed medication. Importantly, the consumption of a balanced diet is recommended, which comprises low levels of saturated fats, low levels of salt, low levels of sugar, plenty of wholegrain, and fiber foods. Regular exercising, about thirty minutes daily, is recommended with gradual duration and intensity increase for enhanced fitness. Further, exercising aids in preserving a healthy weight. Medically, prescribed statins are engaged to lower blood cholesterol levels, aspirin in low-dosage prevent blood clots, and use recommended tablets to minimize blood pressure. Medical surgery is recommended when medication is not sufficient and will depend on the heart disease type and the damage extent.
Symptoms of Heart Disease
The symptoms of heart disease can be categorized based on the four major types of cardiovascular disease. For coronary heart disease, the heart experiences an increased strain due to the blockage or reduced supply of oxygenated blood to the heart muscle, causing chest pain, heart attack, or heart failure. Regarding stroke, the symptoms comprise a drooping face or eye, inability to smile, inability to lift an arm due to numbness or weakness, and slurred or complete loss of speech. The peripheral arterial disease symptoms include cramping or dull leg pain that worsens while walking and eases at rest, loss of leg and feet hair, weakness and numbness in the legs, and persistent ulcers on the legs and feet. The final major heart disease is the aortic disease with aortic aneurysm being the most common. Aortic diseases have no symptoms but can burst and initiate life-threatening bleeding.
A Graph Showing the Increase or Decrease of Cardiovascular Disease
Altogether, in addressing the cardiovascular diseases necessitates for a stable and sustained mechanism, particularly on monitoring and surveillance, the prevention and minimizing of risk factors, and the enhanced health care and management by early recognition and timely treatment. Actions instituted should comprise implementing national goals, measuring outcomes, and advancing partnerships in health policies and strategies. Ensuring the cardiovascular disease response is at the forefront guarantees the international effort in facilitating the development and safeguarding of heart health and human security.
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