Central Nervous System: A Case Study

If it were not for our central nervous system we would not know the smell of a flower or the warmth of the sun. We would not be able to pull our hand away from hot surface or run from danger. The central nervous system is what allows us to experience our senses and react after analyzing a variety of signals. These signals are carried throughout our bodies by specialized cells called neurons which relay the messages to each other. Some of these signals are passed along electrically, while others use a chemical signal called a neurotransmitter in the process of synaptic transmission or neurotransmission. During neurotransmission a neuron before the synaptic cleft releases the chemical signal and it binds to specific receptors on the neuron after the cleft causing activation. After the desired outcome the neurotransmitters must be deactivated via reuptake, certain enzymes, diffusion, or glial cells. Reuptake occurs when the chemical is gathered in the axon terminal it was released from to prevent receptor binding. Enzymatic degradation is the process in which enzymes are used to trump the effects of the

In the example of cocaine use, the drug binds to transporters meant to remove dopamine from the synapse, leaving dopamine without an exit strategy. Amphetamines such as methamphetamine also raise the amount of dopamine left over in the synapse. However, in this case it happens because the drug resembles actual dopamine and hitches a ride into the pre-synaptic neuron on its dopamine transporters. The drug then forces the dopamine out into the cleft. Drugs such as MDMA and LSD have an effect on the neurotransmitter serotonin. This special chemical signal helps to regulate our mood, circadian rhythm, sexual needs and hunger. MDMA also works by preventing reuptake. These are just a few of the countless drugs and neurotransmitters effected by their