Homeostasis in the Human Body - Essay Example

Biology By + 1 Homeostasis in the human body Homeostasis is the process where the human body tries to maintain body environment, the body tries to maintain the equilibrium or balance when there is change in the external or internal environment. There are three mechanisms involved in this process; the receptor, the control center and last effector. The receptor receives information from the surrounding indicating the change taking places and sends the information to the control center where the information is processed and the effector responds to it by opposing the feedback or enhancing the stimulus. The process is ongoing keeping in mind the external and internal environment keep on changing (Matthews et al. 1985). The mechanisms the body uses to maintain homeostasis are negative feedback and positive feedback. The negative feedback is the most common and the example of the negative feedback is regulation of body temperature, blood pressure, and heart rate. For example, when the temperature of the body rises to a certain degrees the negative feedback will take place where the body will try to cool itself and this is done when there is a clear coordination between hypothalamus and the affected organ (Brown & Goldstein 1986). The signal is send to the brains via the receptors. When the brain receives the information it triggers the effectors and in this case the production of sweat where the pores on the skin will have to open and the sweat comes for the cooling process to begin and this will automatically reduce the heart rate as well as the breathing rate. This process is similar to one with a thermostat where the thermostat is set at a certain temperature like 90 degrees for heating reasons. When the temperature reaches the mark, the thermostat will automatically go off until the temperature comes below the set margin. In addition, this process is a continuous one. 1.2 Homeostasis Control Mechanisms Homeostasis control mechanism for temperature When the body temperature falls below normal also called hypothermia, the first thing to be affected will be the brain and this may lead to one not thinking clearly. One will find difficulties in seeking the medical attention due to thinking abnormally. The affected person will experience excessive shivering, breathing will be slowed, one may stumble, experience excessive fatigue, clumsiness, confusion and unconsciousness. Homeostasis control mechanism for heart rate During any physical activity, the heart rate increases because the body requires a lot of oxygen in the body as it is used in the production of energy and the oxygen is circulated in the body by blood. Blood is also used as the coolant when it passes through the vessels. The blood is pumped through the whole body by the heart increasing the heart rate. The rate of breathing also increases during the physical activity because the level of oxygen needed in the body is also high as this oxygen is used in the production of energy that one requires during the physical activity. Homeostasis control mechanism for blood sugar regulation The level of glucose also increases as it is used in the production of energy. Glucose is mixed with adrenaline triphosphate (ATP) in the production of energy that one requires during to perform any physical activity. This process is called oxidation this is where oxygen is used to break down glucose to produce energy (Chrousos & Gold, 1992). 1.3 Failure of the Homeostasis control Mechanism If the homeostasis control mechanism fails, there will be an imbalance of the essential physiological states. Failure to maintain an optimal body temperature may result in hypothermia. On the other hand, failure to balance energy levels may lead to diabetes and obesity. Furthermore, hypocalcemia or hypercalcemia may result from failure to maintain an optimal level of calcium. Finally, if the homeostasis mechanism fails, there will be an imbalance in water levels in the body leading to hyper-hydration or dehydration. All these circumstances pose a great danger to the human body. 2.1 Structure and functions of the urinary system The urinary system plays a major role in maintaining the salt, pH, and water in the homeostasis of the blood. It contains the urethra, kidney, ureter, and urinary bladder. The work of the kidney is to produce, the ureter transports the urine, the work of the urinary bladder is to store urine while that of the urethra passes the urine out of the body. When urine fills the bladder the message is send through the sensory impulses to the spinal cord then to the brain where the response is the bladder contracting to cause urination. The main functions of the urinary system is the excretion of metabolic waste, maintain of the water and salt level in the blood and secretion of hormones. The structure of the kidney includes the renal cortex, the renal medulla, the renal pelvis, and the nephron. Three processes of urine formation include glomerular filtration, tubular secretion, and tubular reabsorption. Glomerular filtration is where water, salt, waste molecules move from glomerulus to the glomerular capsule. Tubular reabsorption is where nutrients and salt molecules are reabsorbed from convoluted tubules to the peritubular capillary network. Tubular secretion is where the secretion of ions and molecules take place from the peritubular capillary network into the convoluted tubules.   2.2 Excretion The hormone ADH controls the amount of water removed from the blood by the kidneys. On a hot day, a person is likely to lose some water and salts through the process of sweating. Thus, the urine on a hot day would be more concentrated and less in volume that on a cold day. This is because the loss of water through sweating causes the concentration of water in the blood to decrease below its set point. This is detected by cells in the hypothalamus (Lynch, C. F., & Cohen, M. B. 1995). These cells are sensitive to the solute concentration of the blood and cause the pituitary gland to release more ADH (anti-diuretic hormone). ADH moves in the bloodstream to the kidney, where it causes the collecting wastes in the kidneys to become more permeable to water, so that more water is re-absorbed back into the bloodstream. This makes the urine more concentrated, so the body loses less water and the blood becomes more dilute (Rubenstein, M., Meyer, R., & Bernstein, J. 1961). The action of ADH is an example of negative feedback. A change in the conditions in the body away from the set point starts a corrective process, which aims to return the conditions to normal. Once the desired internal environment is recreated, the corrective process is switched off. 2.3 Osmoregulation Osmoregulation is the process where the kidney regulates the amount of water and minerals in the body. The salt is removed from the blood in the kidney where a lot of water is needed to make the process a success. Osmoregulation is important because it reduces the amount of toxic substances in the body via urine (Schrodt et al. 1980). Acute glomerulonephritis is the set of the renal diseases in which cause the damages on the surface of the membrane due to inflammation of the glomerular tissue. The damage may lead to the blood coming out through the kidney via urine as the organs that assist in the process of secretion are damaged. 3.1 The structures and functions of the skin The skin system separates and isolates the organism from its surroundings and participates actively in maintaining the organism’s internal environment. Its functions include thermoregulation, tactile sensitivity, participation in the maintenance of water balance, and defense against the radioactive rays (Archer, 2010). The skin has three layers namely epidermis, dermis, and the subcutaneous layer. The epidermis layer is the thin outer layer of the skin, is waterproof, and helps in protecting the inner part of the skin and other organs against bacteria, viruses and other foreign substances. It also protects these organs against trauma. It is thicker in the areas that need more protection like the hand palm and in the sole of the foot. Dermis is the next layer in the skin and is thick layer that contain fibrous and elastic tissue that gives the skin its flexibility and strength. It contains nerve endings, hair follicle, sweat glands, oil glands, and blood vessels. The last layer of the skin is the fat layer that helps in insulating the body from heat and production of heat from the fat cells. 3.2 How the skin controls temperature in the human body The skin regulates the heat in the body through various was this includes the sweat glands that help in the products of the sweat which contains water, salt and other chemicals which one evaporated off the skin it cools the body. It also has the hair follicle that helps in regulation. The follicle produces the hair on the skin that help the skin to warm during the cold seasons, the blood vessels also regulate the temperature of the body, the heat enlarges this vessels making them to circulate the blood around the skin and when there is cold the vessels contracts. The fat layer of the skin helps to insulate the skin against heat and cold and stores energy (Johansson & Vallbo, 1983). 3.3 What happens to the human body if it overheats or overcools? When the human body overheats, the sweat gland releases the sweat that contains salt, water and other chemicals to the top layer of the skin. The sweat then evaporates on the skin to cool the body maintaining the temperature. When the human body overcools the hair follicle expands making the hair on the body to erect and this helps the body to warm, the blood vessels also contracts making the blood to flow away from the skin. The serious injury on the skin damages the layers of the skin exposing the inner part to bacteria, viruses and to radioactive waves. The process of homeostasis will be affected as the skin plays a major role in this process (DeBenedictis et al. 2001). References Archer, C. B. (2010). Functions of the skin. Rooks Textbook of Dermatology, Eighth Edition, 1-11. Johansson, R. S., & Vallbo, Å. B. (1983). Tactile sensory coding in the glabrous skin of the human hand. Trends in neurosciences, 6, 27-32. DeBenedictis, C., Joubeh, S., Zhang, G., Barria, M., & Ghohestani, R. F. (2001). Immune functions of the skin. Clinics in dermatology, 19(5), 573-585. Matthews, D. R., Hosker, J. P., Rudenski, A. S., Naylor, B. A., Treacher, D. F., & Turner, R. C. (1985). Homeostasis model assessment: insulin resistance and β-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia, 28(7), 412-419. Brown, M. S., & Goldstein, J. L. (1986). A receptor-mediated pathway for cholesterol homeostasis. Science, 232(4746), 34-47. Chrousos, G. P., & Gold, P. W. (1992). The concepts of stress and stress system disorders: overview of physical and behavioral homeostasis. Jama, 267(9), 1244-1252. Lynch, C. F., & Cohen, M. B. (1995). Urinary system. Cancer, 75(S1), 316-329. Schrodt, G. R., Alcorn, M. O., & Ibanez, J. (1980). Endometriosis of the male urinary system: a case report. The Journal of urology, 124(5), 722-723. Rubenstein, M., Meyer, R., & Bernstein, J. (1961). Congenital abnormalities of the urinary system: I. A postmortem survey of developmental anomalies and acquired congenital lesions in a childrens hospital. The Journal of pediatrics, 58(3), 356-366. Read More