Respiratory: Human Physiology and Anatomy - Essay Example

The respiratory system is the system in charge of gas exchange. It is made up of various organs involved in the eventual delivery of oxygeninto the cells and the elimination of carbon dioxide from the body. Elements like exercise, body position, and body size affect the exchange of gases, and the diseases like emphysema, pneumonia, restrictive and obstructive respiratory diseases are just some of the diseases which impact on the exchange of gases in the respiratory system. Respiratory System Introduction The respiratory system is the system which primarily supports the exchange of the gases oxygen and carbon dioxide in the body. The respiratory system includes various processes which eventually allow the delivery of much needed oxygen into the cells of the body. This paper will explain how the structure of the respiratory system facilitates ventilation and gas exchange. It will also describe the primary factors affecting gas diffusion through the respiratory membrane; it shall also discuss two pathological conditions (emphysema and pneumonia) which reduce diffusion rate. This essay will also distinguish between restrictive and obstructive respiratory diseases and outline how they are diagnosed. Main body Structure of the respiratory system The respiratory system is a system consisting of various organs and tissues which have specific roles to play in the breathing process. The primary organs which facilitate the exchange of gases include the bronchial airways, the lungs, and blood vessels, as well as various accessory muscles used for breathing (Tieck, 2011). The airways are bronchial tubes where the air from the atmosphere passes on its way to the lungs; these same tubes also bring carbon dioxide out of the lungs (Tieck, 2011). The airways would start with nostrils followed by its associated air passages or cavities: the mouth, the larynx, bronchial tubes and its smaller branches. Air would first enter the body through the nose or the mouth and then goes through the trachea, into bronchial tubes and then to the lungs (Tieck, 2011). The nose contains hairs which partially filter the air from dust particles and other foreign particles. From the nose, the air flows further into the nasal cavity. The nasal cavity has epithelial tissue and blood vessels which basically moisten and warm the air entering its pathways (Tieck, 2011). Mucus is also secreted in the nasal cavity and helps clean the air from any contaminants. The nasal cavity also has cilia which eliminates the dust and other particles from the air, trapping said particles in mucus secretions, and transporting the dust into the nasal cavity and finally into the pharynx (Jango-Cohen, 2004). The mucus is later swallowed and then digested by the stomach acids. The air continues its travel down into the pharynx and the larynx. In order to prevent food and drink from getting into the air passages, the epiglottis acts as a sphincter which shuts the windpipe close when one swallows (Jango-Cohen, 2004). As soon as the air is carried into the lungs by bronchial tubes, the process of air exchange is already taking place. The lungs and the blood vessels which surround the air sacs are the primary organs which assist in exchange of air (Jango-Cohen, 2004). The lungs are located on either side of the breastbone and are found in the inner chest cavity (Jango-Cohen, 2004). For the lungs, the main bronchi split into smaller tubes or bronchioles (Jakab, 2007). These bronchioles continue to branch out and culminate in the air sacs or alveoli. These alveoli are covered with small blood vessels or capillaries which include various arteries and veins which eventually supply oxygen to the different parts of the body (Jango-Cohen, 2004). Through the pulmonary artery carbon dioxide in the blood is delivered to the capillaries around the air sacs (Jakab, 2007). Carbon dioxide and oxygen exchange occurs in these capillaries and carbon dioxide is transported from the blood out into the air during the exhalation process. In exchange, oxygen is pulled into the lungs and moves from the air into the blood (Jakab, 2007). The oxygen is then delivered to the different parts of the body through the same gas exchange process and the heart supports the delivery process. The trachea splits into the left and right lung and the point of branching is known as the carina (Day, et.al., 2009). The right bronchial tube goes into the lobar bronchi, and then into the segmental bronchi, and into even smaller tubes, or the bronchioles (Day, et.al., 2009). A similar setup is seen in the left bronchus. The lungs are connected to the heart and trachea via the roots of the lungs which include the bronchi, pulmonary blood vessels, the lymphatic vessels, as well as the nerves (Lew, 2009). There are various terminal bronchioles attached to the respiratory bronchioles. Alveolar macrophages are also present are also present in the blood (West, 2012). These macrophages fight bacteria by ingesting the microbes which get into the alveoli. In other words, aside from being the location for gas exchange in respiratory and circulatory systems, these alveoli serves as decontaminants for air entering the system (Lew, 2009). Some of the body’s muscles are also essential for the efficient functioning of the respiratory system. The muscles found in the lungs expand and then contract in order to facilitate breathing (Davies, et.al., 2003). These muscles include the diaphragm, the intercostal muscles, the abdominal muscles, as well as the neck muscles (Davies, et.al., 2003). The diaphragm is a dome-shaped muscle found below the lungs; and during the breathing process, it helps push and pull the lungs, allowing for its contraction (Davis, 2000). The intercostal muscles are found between the ribs and they also facilitate the expansion and the contraction of the lungs and chest area during the breathing process. Underneath the diaphragm are the abdominal muscles (Netter, et.al., 1980). These muscles are often used during exertion or physical activities and assist individuals during fast breathing. The neck also assist in the breathing process, especially when the other muscles usually involved in the breathing process are not working well (Britannica Educational Publishing, 2010). During inhalation, the diaphragm would often contract and move downward, thereby increasing space in the chest cavity where the lungs would then expand (Hlastala and Berger, 2001). The intercostal muscles are useful in chest expansion as they pull the rib cage upward and outward when a person is breathing in. When the lungs would expand, the air enters the nose or mouth, traverse the windpipe, and then enter the lungs (West, 2011). Oxygen from the air goes through the capillaries. The red blood cell protein haemoglobin assists in the movement of oxygen from the alveoli into the blood (Khurana, 2005). Carbon dioxide is also transported from the capillaries into the air sacs in the lungs. The gas therefore travels the bloodstream from the right side of the heart via the pulmonary artery. Oxygenized blood coming from the lungs is usually transported via capillaries to the pulmonary vein (Mason, et.al., 2010). The vein transports the oxygenized blood to the left side of the heart. This same side then pumps blood to the other parts of the body. Once there, the oxygen in the blood is delivered to the organs and tissues essential for normal functions (Khurana, 2008). During the process of exhalation, the diaphragm relaxes and moves upward into the chest cavity. The intercostal muscles become more relaxed and in the process they decrease the space in the chest cavity (Rupel, 2008). With the reduced space in the chest cavity, air containing carbon dioxide is eliminated from the lungs. Breathing out calls for no effort unless patients have a lung disease, or they are participating in physical activities (Criner, 2010). During physical exertion, the abdominal muscles also contract and impact on the diaphragm more significantly. This process also pushes air out of the lungs (White, 2005). Factors affecting gas diffusion The primary factors affecting the gas diffusion through the respiratory membrane include: exercise, body position, and body size (Roberts, 1986). The oxygen reuptake often increases with exercise; during exercise, the diffusing capacity is also increased. This is caused by the recruitment and “distension of pulmonary capillaries and also better ventilation/perfusion matching” (Ross University School of Medicine, 2006, p. 3). Another factor affecting gas diffusion includes body position. The diffusion capacity is increased when a person is in a recumbent position mostly because of the higher pulmonary capillary volume as well as the equal management of pulmonary blood flow (Ross University School of Medicine, 2006). Lastly, body size is also a factor affecting gas diffusion; this factor is attributed to the relationship between lung size and surface area (Ross University School of Medicine, 2006, p. 3). Pathological conditions affecting diffusing capacity There are various pathological conditions which impact on the diffusing capacity of the lungs. Most any condition which negatively impacts on the air-blood barrier or any condition which reduces the amount of haemoglobin in the blood would likely decrease diffusing capacity of the lungs (Johnson, 2003). Significant examples include: obstructive lung diseases (emphysema and cystic fibrosis); the interstitial lung diseases (fibrosis); left heart failure causing pulmonary oedema; anaemia; and pneumonia (Johnson, 2003). Emphysema Emphysema is seen when the air sacs or the alveoli in the lungs are damaged, causing difficulty in and shortness of breathing (White, et.al., 2010). It is considered one of the diseases classified under Chronic Obstructive Pulmonary Disease (COPD). Smoking is considered one of the main causes of emphysema. As the condition progresses, the air sacs may develop into large irregular sacs with “holes within their inner walls” (Mayo Clinic, 2012). As a result, the surface areas of the lungs are decreased; moreover, the oxygen entering the bloodstream is also reduced. The primary symptom for this disease includes shortness of breath or difficulty breathing; these symptoms may worsen gradually over time (Mori, et.al., 2012). Due to shortness of breath, affected individuals would often avoid activities which may require them to exert. Eventually, however even at rest, the shortness of breath would also affect the individual (Timmins, et.al., 2012). For worsening conditions, symptoms which cause significant concern include: severe shortness of breath, lips and fingernails turning blue or gray, decreased mental alertness and cognition, and elevated heart rate (Mayo Clinic, 2012). As was mentioned previously, smoking is the main cause for emphysema (Mayo Clinic, 2012). Air pollution, manufacturing fumes, as well as coal and silica dust can also exacerbate the condition (Mayo Clinic, 2012). Risk factors for the development of this disease include smoking using pipes and a significant number of years smoking (Mayo Clinic, 2012). A person’s age can also be a factor which can cause the development of this disease with those in the 40 to 60 age range being the most vulnerable. Exposure to second-hand smoke, occupational exposure to fumes and dust particles; and exposure to air pollution can also increase one’s risk in developing this disease (Mayo Clinic, 2012). Emphysema patients are also at risk for developing various complications including collapsed lungs, heart problems, and large holes in their lungs. Treatment for this condition includes smoking cessation. Bronchodilators can also help manage coughing and shortness of breathing by relieving constricted airways (Mayo Clinic, 2012). Steroids can also relieve the shortness of breath; this option is, however, not recommended for those with high blood pressure and diabetes (Mayo Clinic, 2012). Pulmonary rehabilitation is also recommended for these patients, including supplemental oxygenation for severely affected patients (Mayo Clinic, 2012). Surgical options include lung transplant as well as lung volume reduction (Mayo Clinic, 2012). Pneumonia This is considered an inflammatory condition with the air sacs or alveoli in the lungs primarily affected. This disease is usually caused by bacteria or viruses, including some drugs and autoimmune affectations (Bartlett, 2011). Its main symptoms include coughing, chest pain, fever, difficulty in breathing, chills, increased heart rate, fatigue, nausea, and vomiting (Bartlett, 2011). Older patients may also manifest with confusion or delirium. Risk factors for this disease include: smoking, alcoholism, history or chronic obstructive pulmonary disease, chronic kidney disease, as well as liver disease (Bartlett, 2011). Treatment for this disease is based on its specific cause (Bartlett, 2011). For pneumonia caused by bacteria, doctors would likely administer antibiotics. Relief after antibiotic treatment would likely be seen after 2-3 days, however, rest and sleep are highly recommended even after these 2-3 days of treatment (Yu-San, 2010). Drinking fluids and not smoking during the illness is also highly recommended. For pneumonia caused by viral infections, antivirals are usually administered. Home treatment with rest and plenty of fluids is also recommended (Bartlett, 2011). Restrictive versus obstructive pulmonary disease Obstructive pulmonary diseases are diseases which can cause difficulties in the exhalation of air out of the lungs; on the other hand, restrictive lung diseases cause difficulties in the expansion of the lungs (Ora, et.al., 2009). Both diseases cause shortness of breath upon exertion. Lung damage and the narrowing of the airways which causes the exhaled air to exit slowly is the primary feature of obstructive pulmonary disease (Ora, et.al., 2009). Towards the end of the full exhalation, a huge amount of air is left in the lungs (Johnson, et.al., 2012). For restrictive lung disease, the ability to fill the lungs with air is restricted and the lungs are prevented from fully expanding (Ora, et.al., 2009). Obstructive pulmonary disease is mostly caused by COPD, asthma and cystic fibrosis while restrictive pulmonary disease is mostly caused by interstitial lung disease, sarcoidosis, scoliosis, obesity, and neuromuscular disease, including ALS (amyotrophic lateral sclerosis) (Johnson, et.al., 2012). Both diseases are diagnosed through pulmonary function tests. During pulmonary function tests, the patient expels air forcefully into a mouthpiece (Johnson, 2012). As the patient carries out different breathing adjustments, the machine then evaluated the flow of air into the lungs. Pulmonary function tests can spot the presence of both affectations, including their severity (Vanoirbeek, et.al., 2010). A doctor’s assessment of the patient’s smoking history can also help distinguish these diseases from each other. Laboratory testing and physical assessment can also provide clues about the cause of both diseases. Imaging tests through chest X-rays and computer tomography (CT scan) of the chest can also establish a clear diagnosis (Johnson, 2012). Bronchoscopy is also used to diagnose these diseases. This test is carried out through an endoscope with a camera attached at the end (Johnson, 2012). This test can check inside the airways and also take samples of lung tissue for biopsies (Johnson, 2012). Conclusion The respiratory system is a dynamic system which is essential for body functioning. Its organs and processes manage to deliver oxygen into the cells where the oxygen is used to carry out normal body functions. The diffusion of gases is affected by factors like: exercise, body position and lung size. Conditions like emphysema and pneumonia manifest due to the decreased diffusion of gases through the lungs. Obstructive and restrictive lung conditions manifest with shortness of breath on exertion with obstructive diseases apparent in the difficulties in the exhalation of air in the lungs, and restrictive lung diseases can be seen with the difficulties in the lung expansion. Both diseases are diagnosed through pulmonary function tests, patient smoking, history assessment, chest X-rays and CT scans. References Bartlett, J., 2011. Diagnostic tests for agents of community-acquired pneumonia. Clin Infect Dis., 52 (suppl 4), S296-S304. Bowman, D., 2000. Respiratory pathophysiology / review [online]. Available at: http://science.kennesaw.edu/~bodavis/LECT09.PDF [Accessed 07 December 2012]. Britannica Educational Publishing, 2010. The respiratory system. London: The Rosen Publishing Group. Chien, Y., Su, C., Tsai, H., Huang, A., et.al., 2010. 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