Aspects of Biology - Essay Example

April 19, Biology Assessment 2 Structure and Function of the Body 2 Explain the components of blood and relate the structure of red blood cells to their role in transport. Human blood contains several components. The red blood cells (RBCs) called erythrocyte (Macqueen, 2012) does not have a nucleus. Almost fifty percent of the human blood contains red blood cell type. The red blood cells are responsible for the transport of oxygen from lungs to different parts of the human body. The body’s stem cells actively and continually manufacture the red blood cells. Each red cell contains an estimated 270 million iron-containing hemoglobin type protein molecules. Each hemoglobin molecule binds with four molecules of oxygen to form oxyhemoglobin which transports the oxygen to all the tissues of the body. Hemoglobin also binds with carbon di-oxide to form carboxy-hemoglobin. This is transported back to lungs for exhalation of carbon di-oxide. Blood also contains white blood cells (leukocytes) in less number as compared to the red blood cells. A healthy person contains less than two percent white blood cells. The white cells are produced in the stem cells of bone marrow. The thymus gland present in neck can generate the same white cells. White blood cells act against any foreign particles including bacteria, viruses or any other antigen. They act as phagocytes and destroy these foreign particles. They also discard dead red cells (Macqueen, 2012). Platelets do not contain the nucleus. The platelet is identified as thrombocytes. The platelet helps to heal wounds by enhancing the blood clotting process. The platelets help to plug the injured blood vessels and help in the coagulation of blood. In the absence of platelets blood continues to flow out of the body. Platelets help in the formation of fibrin which acts as a clot (Macqueen, 2012). Plasma is yellowish in color. The plasma helps in the movement of red blood cells and white blood cells all through the body. The plasma transports all the vital nutrients to the body parts and aids in collection and elimination of the waste products from the body (Bam, 2008). 3.1 Explain the structure and function of the circulatory system. The circulatory system consists of heart, lungs and blood vessels. The blood vessels encompass arteries, veins and capillaries (Zimmermann, 2012). The circulatory system helps in transport of nutrients, respiratory gases, hormones and wastes. The transportation is facilitated by intricate network of blood vessels which run from heart (called arteries) and towards the heart (called veins). The system ensures that there is a steady flow of blood, oxygen, nutrients and other much-needed gases throughout the body. The circulatory system allows the transport of hormones to and from different parts of the body (Oxlade, 2015). The circulatory system aids in regulation of body temperature. The circulatory system is also known as the cardiovascular system. The blood carrying system is composed of the veins, arteries, portal vessels as well as the coronary vessels. Heart is four chambered (two auricles and two ventricles) and pumps the blood from ventricles to arteries. Arteries carry the blood to different parts of the body and veins bring it back to the heart. All the arteries carry oxygenated blood except the pulmonary artery and all the veins carry de-oxygenated blood except the pulmonary vein. Pulmonary artery carries blood to lungs for purification where blood gets oxygenated and pulmonary vein brings the oxygenated blood which is pumped to aorta the main artery to transport it to whole body (Web. Human Body System). 3.1 Describe the position of major blood vessels and distinguish between systemic and pulmonary circulation. The above diagram depicts the position of the major blood vessels of the body (Cleveland Clinic, 2015). The pulmonary artery is blue coloured as it brings deoxygenated blood from the heart to the lungs. The lungs supply oxygen to the heart-originated blood. The oxygen filled blood is red coloured. This is called pulmonary circulation (Abramson, 2013). However, it is different than systemic circulation which includes the arteries carrying oxygen-filled blood from the heart to the different parts of the human body. The arteries bring the red-coloured oxygen-filled blood and other much-needed nutrients to different parts of the human body. The veins, blue in colour, bring waste-filled blood from different parts of the human body towards the heart. 4.1 Explain the structure of blood vessels in relation to their function The body has several major blood vessels (Frohlich, 2014). The arteries allow the flow of blood from the heart to different body parts. The arteries are tougher than the veins. The blood that leaves the heart through the arteries is oxygen rich and called oxygenated blood. Except pulmonary artery all the arteries carry pure or oxygenated blood. The arteries also carry much-needed nutrients to the different body parts. The arteries supply oxygen to different body parts through capillaries. The arteries generate beat because the blood comes directly from the heart. The pulse is taken by pressing on one of the arteries. Further, the veins represent another major blood vessel type (Acton, 2012). The veins bring blood from the different parts of the body towards the heart. The blood reaches the heart right auricle; it is pumped to right ventricle which pumps the blood to pulmonary artery and thus blood is transported to lungs for cleaning. The veins are the opposite of the arteries, in terms of blood flow direction. The veins are not as tough as the arteries. The capillaries represent the last major blood vessel type. The capillaries are significantly thin delicate blood vessels. The capillaries are classified as the exit ramps for the blood. Likewise, the same capillaries act as the entry ramps for the blood. The shifting of the blood from the arteries to the veins or from the veins to the arteries is perfected with the maximized use of the capillaries (Carling, 2013). 5.1 Explain the internal and external heart structure. The heart has several parts. The pericardium is firmly placed on the pericardial cavity. The walls as well as the linings of the cavity continually secrete serous liquid. The liquid eliminates friction between the heart and the body parts. The pericardium ensures the heart is firmly in place and cannot be easily dislodged (Filipoiu, 2013). The heart wall is composed of three different layers. The epicardium layer is defined as the outermost heart wall layer. It is the visceral layer of pericardium. The epicardium helps in the lubricating the heart to prevent friction thereby protects the heart (Filipoiu, 2013). The myocardium layer of the heart wall is the thicker. It is found below the epicardium. The myocardium includes the cardiac muscle tissue. The major portion or mass of the heart is the myocardium. The myocardium pumps the blood through the heart. The endocardium layer of the heart wall is located below myocardium. The layer is thinner than the myocardium. The layer lines the inner part of the heart. The smooth endocardium layer prevents blood from attaching or sticking to any portion of the heart, preventing the disastrous effects of blood clotting (Filipoiu, 2013). Human heart has four chambers (Filipoiu, 2013). The chambers are the left atrium or left auricle, right atrium or right auricle, left ventricle and right ventricle. The atrium is smaller than the ventricle. The atrium is slimmer, contains less muscular walls compared to the ventricles. The ventricles pump blood from the heart to the different parts of the body through arteries. The chambers located on the right side of the heart are smaller in size compared to the chambers on the left side of the heart. The right side of heart transports pulmonary blood to the lungs. The left side pumps oxygen rich blood to different body parts. The heart has valves (Filipoiu, 2013). The two atrioventricular valves are located between the atria and the ventricle. The atrioventricular valves are the mitral/bicuspid (two cusps) valve and the tricuspid (three cusps) valve. The atrioventricular valves ensure blood only travels from the atria to the ventricle. There are two types of semilunar valves, the aortic valve and the pulmonary valve. The semilunar valves push blood from the heart to the arteries. 5.2 Explain the role of the heart and the cardiac cycle. Role of heart is to ensure that blood continually flows throughout the body (Ourselin, 2013). The cardiac cycle is grounded on the pumping or contracting action of heart. One cardiac cycle incorporates all activities within one heart beat. The cardiac cycle is composed of two phases. The first phase is the diastole phase, during this phase; the ventricle is in a relaxed state. Likewise, the same phase is characterized by blood inflow into the heart. The blood flows into both the ventricles of the heart. The second phase is the systole phase, where the ventricles contract. Under the same phase, the blood is pumped from the heart through the arteries to the different parts of the body. One cardiac cycle includes entry of blood into the heart and release of blood into the arteries (Ourselin, 2013). 5.3 Summarise how heart rate is modified according to the needs of the body. The heart rate is significantly modified by two factors. The first factor is the intrinsic factor. The cardiac tissue self regulates the heart rate. The same factor retains an automatic heart beat rhythm within intervention from the person (Ernst, 2013). The second factor is the extrinsic factor. The extrinsic factors include the entry of hormones. The nervous system sends signals that will change the heart rate. The central nervous system sends feelers that alter the current heart rate. For example, a person sitting still while watching television show has a slower heart rate than a person who is currently running around the block. The central nervous system sends signals to the person upon hearing that he or she must get ready to fight in the next karate tournament round. Consequently, the heart rate increases as one prepares to face the bigger martial arts tournament opponent. Some medicines affect the heart rate. For example, inderal medicine or lopressor medicine brand will reduce the heart rate. Likewise, the hot day or heat, wind blowing, and cold air significantly contribute to the changes in the heart rate (Ernst, 2013). 6.1 Explain the role of hydrostatic and osmotic pressure in the formation and re-absorption of tissue fluid. Hydrostatic pressure- It is the pressure exerted by blood or plasma on the lateral wall of blood vessels. When the intravascular hydrostatic pressure is high the fluid will move from intravascular compartment to extravascular compartment (tissues). Hydrostatic pressure is increased in following conditions- exercise, stress, and hypertension (Himansu, 2010). Osmotic pressure- it is determined by the concentration of salts, plasma proteins etc. Generally when the salt load is high, osmotic pressure increases in the blood vessels. Due to this built-up of intravascular osmotic pressure the fluid from extravascular compartment will move to intravascular compartment and vice versa. Low osmotic pressure is seen in cirrhosis of liver as a result there is a transudation of fluid from intra to extra-vascular compartment (tissues) resulting in oedema (Himansu, 2010). 6.2 Explain oedema and some possible causes Oedema can be described as the unhealthy fluid retention that leads to swelling (Donnelly, 2009). Under the condition, some or all of the body tissues contain trapped excess fluids. The swellings often occur in legs, arms, feet, as well as hands of the patient. One of the popular names of oedema (edema) is dropsy. There are several causes of oedema (Donnelly, 2009)- hypoprotenemia, liver (cirrhosis) and kidney disease (nephritic syndrome), protein energy malnutrition (PEM), right-sided heart failure. Localized oedema occurs due to constant sitting, constant standing, fluid accumulation in lower extremities due to stasis of blood. Physiological oedema occurs due to pregnancy or menopause. Drug induced oedema due to consumption of steroids. 7.1 Explain the structure of the respiratory system. Respiratory_System The above diagram shows the structure of the respiratory system (Rogers, 2010). It involves nostrils, larynx, trachea, bronchi, bronchioles, alveoli and alveolar sacs. The respiratory system is responsible for breathing process. The process includes inhaling oxygen and the exhaling carbon dioxide. The above diagram shows the names of the different breathing structures. The system has both the upper airways as well as the lower airways. The lungs accept oxygen and removes carbon dioxide. The diaphragm helps ensure the breathing (respiration) process works perfectly. The ribs protect the lungs from possible externally caused damage. The nose, pharynx, and sinuses filter the air entering the lungs from dust and other unwanted materials. In the alveolar sacs gaseous exchange takes place. 7.2 Explain how breathing and gas exchange occur and how oxygen is carried around the body. The breathing process includes the diaphragm movements (Lonescu, 2013). The diaphragm muscle moves downward to allow oxygen to enter the lungs. The diaphragm moves up to expel the carbon dioxide gas. When a person inhales oxygen, the nose filters, moistens, heats, and pushes the oxygen to the throat. Next, the oxygen moves into the windpipe, right past the body’s cords (vocal). The air is pushed towards the lungs. The lung’s bronchi contain sacs. The sacs (alveoli) transfer the oxygen into the blood. The red blood cells exchange its loaded carbon dioxide gas with the oxygen gas. The lungs expel the carbon dioxide gas. 7.3 Explain how diseases such as asthma and emphysema compromise the uptake of oxygen and the effect of smoking on this system. Asthma is characterized by inflamed airways (Chaitow, 2014). The inflamed airways are narrowed. Consequently, the lungs inhale lesser amounts of oxygen than the normal asthma-free person. Symptoms of Asthma patient include coughing and breathing difficulty. Emphysema is characterized by air trapped in the lungs (Jones, 2011). The trapped air prohibits the entry of inhaled oxygen into the patients’ blood. The trapped air prohibits the exit of carbon dioxide from the lungs. Often, smoking triggers the emphysema condition. Smoking reduces the quantity of oxygen intake during each inhaling activity (Jones, 2011). Carbon monoxide, instead of oxygen, goes into the patients’ blood. Smoking reduces the capacity of the bronchi of lungs and trachea to extricate mucus, reducing the amount of oxygen quantity intake during the oxygen inhaling activity. Acidic cigarette smoke inflames and swells the breathing linings, reducing oxygen quantity intake. Assessment 3 8.1 Describe and explain the structure and function of excretory system The excretory system focuses on removing wastes from the body (Grant, 2014). The system centers removing liquid wastes. Urination removes liquid wastes from the body. The excretory system encompasses kidneys, ureter, urinary bladder and urethra. The kidney helps in the excreting of body wastes and maintains the chemical composition of the body. The mechanism involves collection of water and waste products from the blood and this is then excreted in the form of urine. The urine is stored in the urinary bladder from where by the act of micturation it is excreted through urethra. Thus kidneys remove the wastes from the blood. Kidneys are placed inside the back ribs and are responsible for the regulation of chemical composition of fluids in the body. Each kidney has renal cortex which is the outer portion of the kidney and renal medulla which is present on the inner side. Renal medulla contains millions of nephrons. Renal portal system is responsible for filtration of waste products. Renal artery supplies blood to the kidney. Renal artery is responsible for bringing the blood containing oxygen and urea from aorta. Renal vein takes the filtered blood from the kidney to the inferior vena cava. Filtration is done by the capillary network of the vascular system. The capillary network releases the filtered blood into the renal artery. The urine is formed in the nephrons which are collected in the collecting duct. From the collecting duct urine is passed to the ureter. Each kidney has a ureter which carries urine from the kidneys and transports it to the urinary bladder. The urinary bladder is muscular and expandable sac. It retains the urine till it is discharged through urethra. Urethra is a small tubular structure from where urine is discharged out of the body. Urethra is surrounded by muscles which allow urethra to control the process of urination. Each kidney is made up of several tiny units called the nephrons. These nephrons are responsible for filtration of blood that passes through them. The structure of nephrons involves various capillaries which pass through the structure called glomerulus. There are various slits in the glomerulus which prevent the blood cells and larger molecules from entering inside. Blood from the renal artery enters the glomerulus. The glomerulus then filters the blood, water and solutes are filtered from the blood and enter the nephrons. The nephrons are tubular structures contains Bowman’s capsule and Loop of Henle with network of capillaries. Structure: Excretory System The above diagram shows the structure of excretory system (New Health Guide, 2014). The kidney transfer urine wastes to the ureter. The kidney sends the blood’s liquid wastes to the ureter. The ureter brings the urine from the kidney to the urinary bladder. The bladder holds the urine. When the bladder is full, the bladder signals the urethra to release the wastes. The urethra releases the liquid waste through urination. The acidic condition as well as the concentrations of numerous substances present in the blood is retained by the process of diffusion as well as active transport of collecting tubules. The composition of urine involves 95 percent water and remaining waste products. The waste products include potassium, sodium bicarbonate, amino acids, glucose and uric acid. Kidney is an important organ of the body any kind of kidney injury may lead to poor fluid management. Diuretics may obscure the fluid accumulation-mortality association. However, diuretics are found to be ineffective in prevention as well as treatment of acute kidney injury. It is observed that most of the cases of kidney failure is due to renal nonrecovery in acute kidney injury. Diuretics are known to induce intravascular hypovolemia and lead to renal dysfunction as well as electrolyte imbalance. It is therefore majority of the clinicians avoid prescribing diuretics in acute kidney injuries (Grams et al., 2011). References: Abramson, D, 2013, Blood Vessels and Lymphatics. London: Elsevier Press. Acton, Q, 2012, Veins. London: Scholarly Press. Bam, B., 2008, Beginners Guide to Blood Cells. London: J. Wiley & Sons . Brown, T, 2011, Introduction to Genetics. London: Garland Science Press. Carling, E, 2013, British Surgical Practice. London: Elsevier Press. Cedar, S, 2012, Biology for Health. London: Palgrave Macmillan Press. Chaitow, L, 2014, Recognize and Treating Breathing Disorders. London: Elsevier Press. Cleveland_Clinic., 2015, Illustration of Blood Vessels. Retrieved April 2, 2015, from http://my.clevelandclinic.org/services/heart/heart-blood-vessels/illustrations-blood- vessels Donnelly, R, 2009, ABC of Arterial and Venous Disease. London: J. 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