This system is based on electrical and neurochemical activity performed by the brain. Presynaptic cells release chemicals known as neurotransmitters into synapses, which allow an electrical or chemical signal to pass to another cell. These signals eventually travel their way to the brain via the central nervous system, where in turn the brain releases a message that directs the body on how to deal or cope with the stimulus.
There are many known diseases that can influence this process causing neurological problems, amongst drug abuse, alcoholism and brain damage is illnesses that are degenerative diseases that cause damage to the nerve cells which in turn leads to behavioural and psychiatric problems, one of these being Alzheimers disease (Alzheimer 1907). Alzheimers is the result of decreased brain size which occurs when a huge portion of nerve cells die and the tissue in the brain reduces in size.
The detoriation and reduced levels of the nerve cells means that nerves are not able to respond as well as they should be able too. This in turn causes chemical disruption which then slows down the transmission of chemical impulses. Alzheimers affects the different areas of the brain. It causes the cortex to shrivel up which damages areas required for thinking, planning and remembering. It causes the hippocampus to also shrink which is required to help build new memories.
The disease also makes the ventricles (fluid filled spaces in the brain) to grow larger than normal. Scientists have discovered that patients diagnosed with Alzheimers tend to have fewer nerve cells and synapses in the brain. The brain holds abnormal clusters of proteins (plaques) which tend to build up between the nerve cells which make it harder for the synapses to perform their job of transferring messages to another cell. This means the nerve ells eventually die and develop tangles which are twisted strands of protein. These tangles destroy the cell transport system by preventing nutrients and other essential supplies travelling too other cells, therefore these cells eventually die. Due to the cells dying the brain begins to shrink therefore sacrificing areas of the brain that is required for everyday life, this than leads onto behavioural problems caused by insufficient neural activity.
An Alzheimer suffer will show repetitive behaviour where they constantly ask the same question or perform the same action continuously; this is due to the damage of the brain. They will also become restless and suffer with sleep deprivation which can lead to agitation and frustration. This is all the result of change in neural activity and despite drugs being prescribed the patient will still experience anxiety and depression which leads to violent and abusive outbursts.
A common behavioural symptom is also experiencing hallucinations and delusions that are frustrating for both the sufferer and their support network. These symptoms and effects of Alzheimers are all due to the disruption in neural activity which is caused by the shrinking of the brain due to inadequate functioning of nerve cells. The effect of different areas of the brain shrinking means that they are not able to perform their job as well as a healthy brain can.