"Alzheimer's Disease and Cognitive Abilities" is a smart example of a paper on the disorder. The brain is known to be the control center of the bodily functions and activities of a human being. It is designed in such a way that impulses pass in the brain through neurons which then electrically stimulate parts of brains. These parts of brains then send out impulses again to the specific organs where a reflex action is required. Cerebral Cortex is a part of the brain which primarily is related to the intelligence and cognitive abilities of an individual.
Several diseases may arise if this part of the brain is affected and one such disease is Alzheimer's Disease. Alzheimer's is mostly seen in individuals who are above the age of forty-five and it principally develops into dementia in its later stages. It is characterized by loss of cognitive abilities which occurs due to the loss of normal brain functions. In the latter stages of Alzheimer's Disease, the sufferer becomes totally disoriented and shows memory loss such that he is not able to recognize his very close family members.
(Evans et al, 1989; Gao et al, 1999). The primary feature of Alzheimer's Disease is the atrophy of the cortex. But in some cases, it is seen that neuritic processes may accumulate, abnormalities in the cerebral nucleus may occur or amyloid angiopathy may be seen. It is seen that Alzheimer's Disease does not show any symptoms early at age but after a person reaches 50 the symptoms become obvious. As an individual ages the chances of the disease increase even more often reaching a level of 40% in individuals who are in their eighties (Evans et al, 1989; Gao et al, 1999; Strauss et al 1999 ).
Studies on the disease have shown that cortical atrophy is the major cause of the disease. The cerebral sulci become more prominent in the temporal, frontal, and parietal lobes. To cover up for this atrophy usually, the ventricle in the brain enlarges. Microscopic studies have shown that neuritic plaques and neurofibrillary tangles accumulate along with amyloid angiopathy. Neuritic plaques are spherical neuritic processes that surround the central amyloid core in Alzheimer's.
Neurofibrillary tangles are a group of filaments that are found in the cytoplasm of the neurons that usually surround the nucleus. Amyloid angiopathy is a sign of Alzheimer's Disease but it can also be found in other diseases. It is believed that Alzheimer's later progresses to dementia in individuals because of loss of choline acetyltransferase, synaptophysin immunoreactivity, and loss of synaptic transmission. It is believed that Alzheimer's is primarily caused by a protein known as Aβ . Aβ is difficult to be degraded and is hence known to possess the properties to be neurotoxic.
This protein is believed to be synthesized by the processes done by APP. APP is also a protein that is found on the cell surfaces. Normally APP is cleaved by an activity known as an α -secretase activity. This α -secretase activity cleaves APP after which APP cannot form the neurotoxic Aβ protein. In Alzheimer much of this APP is endocytosed after which it undergoes several processes to form the neurotoxic protein (Mumm 2000). The enzymes which carry out these processes are BACE-1 or β secretase and γ -secretase.
β secretase acts on the APP in the transmembrane domain whereas γ -secretase acts on the APP which is inside the transmembrane domain. Alzheimer's is also believed to have genetic influences because of which APP secretes this neurotoxic protein. Three of the recognized genes which code for APP are found on chromosome 21, 14, and 1. (42) Mutations can also cause Alzheimer's Disease and it is known that a mutation in a gene on chromosome 19 can increase the risk of Alzheimer (Strittmatter et al 1993). It has been found that hormones and Alzheimer's Disease may also have something in common.
An effect on insulin has been recently studied which is somehow linked to the onset of the grave disease. Insulin is a hormone secreted by the pancreas which helps in the absorption of glucose in the cells. Diabetes and Alzheimer's Disease have been linked together. A new and interesting finding by the researchers at the US Brown Medical School indicated the prevalence of the third type of diabetes which was classified as type 3 diabetes.
It has been discovered that apart from the pancreas the brain also works towards the secretion of insulin. This insulin works as a regulator of the metabolism of glucose mainly in the brain and does not mainly have an effect on the body's blood glucose levels. The neurologic cells of the brain are not able to maintain normal function in the absence of this insulin which leads to loss of function of the brain cells. This accounts for Alzheimer’ s disease and a link has been found out between diabetes type 3 and this neurological condition (BBC News, 2005) Estrogen another hormone in women is known to have a direct link with Alzheimer's Disease in women.
It is known that hormone therapies in women have helped them to cope up with the early onset of Alzheimer's Disease. But research done showed that if women had hormone therapy for a long time then they might develop greater risks of acquiring Alzheimer's Disease (Exercise, estrogen, and executive function, 2008). In conclusion, it can be said that Alzheimer's Disease is a disease that causes loss of cognitive abilities because of cortical atrophy.
Its onset is linked to both nutrition and hormonal imbalance. Although the disease does not have any possible cure it can be managed by certain therapies and medications. Further research is still needed to clarify the effects of both nutrition and hormones on the onset of Alzheimer's Disease. Folate and other vegetable juices have proved to be very beneficial to reduce the risk of Alzheimer's disease whereas copper and saturated fats are increasing its risk. The hormone insulin and estrogen are linked with Alzheimer's Disease and to balance these hormones in the body it is necessary that extensive researches are carried out.
(Exercise, estrogen, and executive function, 2008).
BBC NEWS . Study suggests 'type 3 diabetes'. 2005. http://news.bbc.co.uk/2/hi/health/4315609.stm
Evans DA, Funkenstein HH, Albert MS, Scherr PA, Cook NR, Chown MJ, et al. (1989). Prevalence of Alzheimer's disease in a community population of older persons. Higher than previously reported. JAMA : the Journal of the American Medical Association. 262 (18), 2551-6.
Gao S, Hendrie HC, Hall KS, & Hui S. (1998). The relationships between age, sex, and the incidence of dementia and Alzheimer disease: a meta-analysis.Archives of General Psychiatry. 55 (9), 809-15.
Mumm JS, & Kopan R. (2000). Notch signaling: from the outside in. Developmental Biology. 228 (2), 151-65.
(2008). Exercise, estrogen, and executive function. Harvard Mental Health Letter, 24(8), 6. Retrieved from Health Source - Consumer Edition database.
Strittmatter WJ, Saunders AM, Schmechel D, Pericak-Vance M, Enghild J, Salvesen GS, et al. (1993). Apolipoprotein E: high-avidity binding to beta-amyloid and increased frequency of type 4 allele in late-onset familial Alzheimer disease. Proceedings of the National Academy of Sciences of the United States of America.90 (5), 1977-81.
von Strauss E, Viitanen M, De Ronchi D, Winblad B, & Fratiglioni L. (1999). Aging and the occurrence of dementia: findings from a population-based cohort with a large sample of nonagenarians. Archives of Neurology. 56 (5), 587-92.