Evaluate the Role of Chemical Transmitters in Explaining Behavioural Disorders

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Evaluate the Role of Chemical Transmitters in Explaining Behavioural Disorders

All behaviour is provided by the nervous system from a blinking eye to talking. Everything we do relies on the integration of numerous processes within the body, which is controlled by the nervous system (Atkinson et al. 1990). It wasn’t until the late 19th Century with the development of stronger magnifying lenses and staining techniques that the nervous system could be looked at in detail (Wickens, 2005). The integrating units of the nervous system are specialized cells called neurons. There are approximately 1 billion neurons in a human brain. What makes them more astonishing is that each single neuron is connected with around 10,000 others (Wickens, 2005).

There is great variation between neurons but they all consist of common characteristics. They all encompass a cell body, plus branching from this that receives neural impulses are dendrites. These impulses are then passed down a single thin tube like branch projected from the cell body termed an axon. At the end of the axon there are further branches that end in small swellings called synaptic terminals (Kalat, 1992). In the late 1800s Santiago Ramon y Cajal discovered that these synaptic terminals do not merge with the next neuron, rather there is a small gap between the terminal and the neuron (Wickens, 2005). These junctions were termed synaptic gaps.

There are two types of synapses in the nervous systems, electrical and chemical, most of which are chemical. In these chemical synapses, arrival of an impulse in the presynaptic neuron triggers the release of a chemical substance termed a neurotransmitter. Once an action potential reaches the synaptic knob of the presynaptic neuron, calcium channels in the membrane open. This increase in intercellular concentration of calcium stimulates the movement of vesicles, which contain neurotransmitters that fuse with the membrane and release a neurotransmitter into...
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