Homeostatic Control of Blood Glucose Levels
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Introduction
Adnan Undre Homeostatic Control of Blood Glucose Levels Glucose is an essential substance in the body as it the primary source of energy for all biological functions and is indeed the only form of energy which can be used by the brain and central nervous system. The ideal level of blood glucose is 80 - 90mg of glucose per 100mls of blood. However this level is not static - it oscillates due to changes in the body which are brought about by actions such as eating a meal, exercising, or not eating for long periods. If blood glucose levels drop or rise dramatically there may be serious consequences such as hypo- or hyperglycaemia which can both cause death. Thus it is necessary for blood glucose levels to be regulated and this is achieved through homeostasis. To work effectively homeostasis requires an effective receptor to detect variations from the norm and a negative feedback system where antagonistic processes work to redress any variations as they occur. By examining the mechanisms of the homeostatic control of blood glucose levels it should be possible to explore the consequences of a breakdown of this part of the endocrine system. ...read more.
Middle
Firstly, it stimulates the process of glycogenolysis whereby the liver and muscle cells convert glycogen into glucose to be discharged into the blood. In addition, it increases gluconeogenesis so that more glucose is synthesised from protein and fat sources. However if glucagon is allowed to encourage the production of glucose unchecked, the liver will begin to produce ketones which dangerously disrupt the acid/base balance in the body. The two antagonistic processes described above combine to homeostatically regulate and maintain blood glucose at an appropriate level - their actions are summarised in the diagram below. Although insulin and glucagon are the hormones that have the greatest effect on blood glucose other hormones also play a part. Somatotrophin, adrenaline and corticosteroids all work in conjunction with glucagon to counteract low blood glucose levels. In some people these essential control mechanisms are inactive and this results in a condition known as diabetes mellitus, of which there are around 700 000 diagnosed cases in the UK. The disease can be classed as either Type 1 (insulin dependent) or Type 2 (non-insulin dependent) diabetes, both of which have different characteristics and causes. ...read more.
Conclusion
Due to osmosis the glucose takes a lot of water with it so the volume of urine is abnormally large and this results in the diabetic also being dehydrated and always thirsty. As cells are forced to metabolise fats and proteins for energy in the absence of glucose, ketones are produced which give the sufferer breath which smells of acetone. As mentioned earlier, the disruption of the body's acid balance as a result of ketone production is the main cause of coma and death in Type 1 diabetics. Again, due to the metabolism of fats diabetes will also manifest itself as weight loss, especially in Type 1 cases. In the long term both types have potential to cause heart disease, kidney and nerve damage, stroke and blindness if not managed well. As stated above both types are currently treated through a healthy diet combined with medication, but there are other treatment prospects to consider in the future such as Islet Cell Transplantation. Perhaps the most interesting is the work by the US Department of Energy on an artificial pancreas which if developed could free diabetics from the rigours of current treatments and ensure accurate control of blood glucose at all times. Word count 1098 1 ...read more.
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Here's what a teacher thought of this essay
4 star(s)
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A good overview of blood glucose regulation and diabetes using A level biological terminology correctly throughout. The role of negative feedback has been neglected however.
Marked by teacher Adam Roberts 05/09/2013
