Respiratory System and Chronic Obstructive Pulmonary Disease - Essay Example

Respiratory System and Chronic Obstructive Pulmonary Disease Introduction Chronic obstructive pulmonary disease or COPD is a disease of the airways in which there is progressive and permanent obstruction of the airways that occurs in emphysema, chronic bronchitis or both. This disease causes pathological changes in the airways and the alveoli, thus affecting gas exchange (Sharma and Graham, 2005). This essay discusses the respiratory system with reference to COPD. The Respiratory System Lungs are the main place of gas exchange in our body. In the lungs, carbondioxide from the blood is removed and the blood is oxygenated. Air enters the nostrils and from there and travels through the nasopharynx, glottis, trachea, bronchi and through the bronchioles into the alveoli. Gas exchange occurs in the alveoli. There are about 300 million alveoli running to about 160m2 area. Lungs expand when there is increase in the volume of thoracic cavity. During inspiration, there is contraction of the external intercostal muscles which lift the ribs up and out and there is contraction of the diaphragm which draws the ribs down. During expiration, these processes are reversed. The elastic recoil of the lungs makes them to come back to their resting volume. At rest, a normal adult human being breathes about 15- 18 times exchanging 500ml of air each time. Chronic bronchitis and emphysema To diagnose a patient as having chronic bronchitis, the patient must suffer from chronic cough for atleast 3 months in one year for 2 consecutive years. The cough is accompanied by sputum expectoration, but there is no other cause for sputum production. There is enlargement of the mucus glands in the lungs, inflammation of the airways and thickening of the bronchial walls. Because of these pathological changes, there is loss of supporting alveolar attachments leading to deformity of the airway walls, which inturn results in narrowing of the airway lumen and decrease of airflow through it (Sharma, 2006) In emphysema, the alveoli are enlarged abnormally and permanently. There is also destruction of the alveolar walls and loss of elastic recoil. There are 3 types of emphysema: centriacinar emphysema, panacinar emphysema, and distal acinar emphysema or paraseptal emphysema (Sharma and Graham, 2005). Patients with emphysema typically suffer from breathing difficulty. People with COPD have rapid decline in forced expiratory volume or FEV. FEV is the maximum amount of air that is possible to be exhaled within a specified period of time after maximal inhalation. Causes of COPD The most common cause of COPD is smoking in the form of cigarette smoking or exposure to tobacco smoke either due to passive smoking or environmental tobacco smoke. Other causes include air pollution, airway hyperresponsiveness and alpha1- antitrypsin deficiency. Conclusion COPD can occur either due to chronic bronchitis or emphysema or both. In chronic bronchitis, there is hypertrophy of the mucus glands and inflammation and thickening of the airways resulting is air trapping and decreased gas exchange. In emphysema, the alveoli are damaged and the lungs lose elastic recoil, thus again affecting gas exchange. The most common cause of COPD is cigarette smoking. The Heart and Coronary Artery Disease Introduction Coronary artery disease or CAD is a disease of the heart in which there is reduced or absent blood flow in one or more than one arteries of the heart. Other than a few congenital conditions, most of the times, coronary atherosclerosis is the cause for obstruction in the arteries. In atherosclerosis, certain plaques are formed which are composed of fatty material, scar tissue and calcium. These plaques either narrow the coronary arteries and cause reduction in blood flow or rupture and form clots which block the arteries. When the blockage of the arteries is sudden and complete either due to the plaque or the clot, myocardial infarction occurs which is known as heart attack. When there is partial block, decreased blood supply to the heart occurs and this causes chest pain which is known as angina. This essay discusses the function of the heart with reference to CAD. The Heart Heart is a four chambered organ occupied in the central portion of the thorax with mild shift to the left side of the chest. The four chambers are right atrium, right ventricle, left atrium and left ventricle. Blood returns to the heart from all over the body through veins which ultimately drain into the venacavae; the superior venacava takes blood from the upper parts of the body and the inferior vena cava takes blood from the lower part of the body. Both the venacavae then drain blood into the right atrium of the heart. From the right atrium, blood is pumped into the right ventricle from where blood is pumped into the lung vasculature through pulmonary artery for oxygenation and removal of carbon-di-oxide. The oxygenated blood enters the left atrium of the heart through pulmonary veins. From here, blood is pumped into the left ventricle. From the left ventricle, blood is ejected into the aorta which then branches out and supplies oxygenated blood to all parts of the body. The entire process occurs in just one heart beat! The heart is supplied by the branches of right and left coronary arteries which encircle the heart. The right coronary artery supplies the right and inferior parts of the heart. The left divides into 2 large branches: the left anterior descending branch which supplies the front of the heart and the left circumflex branch which supplies the left lateral and posterior aspects of the heart (Wedro, 2008). Risk factors for coronary artery disease or CAD 1. Age: CAD mainly occurs in those older than 45 years. However, in cocaine abusers, in those with type-1 diabetes mellitus, hypercholesterolemia and positive family history of heart attacks, the condition may even manifest at an earlier age (Fenton, 2008). 2. Male gender: In persons between 40 and 70 years, there is a male predilection for heart attack. In those older than 70 years, no sex predilection occurs (Fenton, 2008). 3. Sedentary lifestyle: 4. Smoking 5. Abnormal lipid profile 6. Diabetes mellitus 7. Hypertension 8. Type-A personality 9. Family history Symptoms of myocardial infarction The 3 main symptoms of heart attack, also known as classic symptoms are chest pain or discomfort associated with shortness of breath, severe sweating and nausea. The classic chest pain is usually described by the patients as tightness in the central portion of the chest with radiation of pain to the jaw and also down the arm. Many patients do not develop these symptoms and hence it is important to know other manifestations also like: jaw ache, indigestion, only shortness of breath, pain only in the shoulders and arms and only nausea and vomiting (NHLBI, 2008). Many a times, in women, in the elderly and in those suffering from diabetes, the symptoms can be so minimal, vague and atypical, that heart attack can be easily missed. In these patients, the only complaint may be tiredness. Other atypical symptoms of heart attack include abdominal pain, anxiety, cough, diaphoresis, lightheadedness, syncope and wheezing (Fenton, 2008). About 50% of heart attacks are clinically silent and may go unrecognized. Hence in those with high risk for heart attack, a high index of suspicion should be maintained for heart attack (Fenton, 2008). Prevention of CAN Every individual, especially those with family history of heart attack must modify his or her diet and lifestyle in such a way that development of coronary artery disease is prevented. This attitude has to develop as early as possible in adulthood. Smoking increases the risk of heart attack and this must be stopped. Even a single cigarette can increase the risk of heart attack. Hypertension, high cholesterol and diabetes must be dealt with appropriately. Sedentary lifestyle must be given up and the individual should exercise regularly. Those at increased risk of heart attack may prevent it by taking a baby aspirin a day, along with other measures. These measures also prevent stroke and peripheral vascular disease. Every individual must develop an emergency plan to deal with heart attack, because it can occur any where, anytime and to anyone! (Wedro, 2008). Conclusion Atherosclerosis is the commonest cause of CAD. This condition causes development of plaques in the coronary arteries, thus causing narrowing of the arteries or complete blockage of the arteries. Reduction in the blood supply to the heart results in angina and complete block of blood supply results in myocardial infarction. Good life style, exercise, proper diet and proper treatment of diabetes and hypertension can decrease the risk of CAD. References Fenton, D.E. (2008). Myocardial Infarction. Emedicine from WebMD. Retrieved on 25th April 2009 from http://emedicine.medscape.com/article/759321-overview NHLBI. (2008). Heart Attack. U.S. Department of Health and Human Services. Retrieved on 25th April 2009 from http://www.nhlbi.nih.gov/health/dci/Diseases/HeartAttack/HeartAttack_WhatIs.html Sharma, S., and Graham, L. (2005). Chronic obstructive pulmonary disease. EmedicineHealth. Retrieved on 25th April 2009 from http://www.emedicinehealth.com/chronic_obstructive_pulmonary_disease_copd/page17_em.htm Sharma, S. (2006). Chronic Obstructive Pulmonary Disease. Emedicine from WebMD. Retrieved on 25th April 2009 from http://emedicine.medscape.com/article/297664-overview Wedro, B.C. (2008). Heart Attack. Emedicinehealth. Retrieved on 25th April 2009 from http://www.emedicinehealth.com/heart_attack/article_em.htm Read More