Beh 225 Brain Response of Behavior

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Axia College Material
Appendix C

Brain Response of Behavior

Part I

Note: Parts II and III follow below, complete all three.

Run Multimedias 2.3 and 2.4

* Go to the Web site
* Click text: Psychology: An Introduction (12th ed.)
* Click “2” on the select a chapter tool bar.
* Click Live!Psych on the left hand menu.
* Select 2.3 and 2.4.

Write a 350- to 700-word response to the following: Explain the communication process of neurons in the brain. List some common neurotransmitters and describe their effect on behavior.

<Insert Response Here>

The communication process of neurons in the brain occurs through an electrochemical process. Neurons pass neurotransmitters through the dendrites, which are attached to the ends of each neuron and receive messages from neighboring neurons. The chemical messages that are passed from one neuron to the next cause an action potential. This occurs when the receiving neuron accepts the right amount of the correct message. Once the message is received, the neuron will then send neurotransmitters to the next neuron through the axon. After the neurotransmitters pass through the axon they are released through the terminal buttons. Then, the nerve impulses pass to a nerve cell at a site called the synapse. At this site, the impulse is transmitted to the other cell. The neurotransmitters must pass through a gap between the cells. This gap is called the synaptic cleft. Through this gap, the neurotransmitters are allowed to flow out of the terminal buttons of one neuron. After the neurotransmitters are released, they pass through the synaptic cleft and are received by the dendrites of the next neuron. The neuron that sends the neurotransmitters is called the presynaptic neuron, whereas the receiving neuron is called the postsynaptic neuron.

The terminal buttons of the presynaptic neuron hold the synaptic vesicles. These sacs filled with neurotransmitters pass chemical messages upon the release to the next neuron. The release of chemicals out of the synaptic vesicles is done at the terminal buttons, which is caused by an action potential. This action then pushes the molecules over the synaptic cleft to the receiving dendrites of the postsynaptic neuron.

Finally, receptor sites attached to the dendrites of the postsynaptic neuron connect the neurotransmitter molecules that pass over the synaptic cleft. The molecules only touch the receptor sites briefly, an action that is done to ensure that they fit within the particular shape on the dendrite. The neurotransmitters from the presynaptic neuron must fit into the receptor sites of the postsynaptic neuron in order for the message to be accepted. If the neurotransmitters do not fit into the receptor sites, the message will not be received into the dendrites of the postsynaptic neuron.

When discussing neurotransmitters, it is important to know that each one has an effect on the specific nerves. The different types are numbered in hundreds that effect different nerve circuits in a specific way. Excitatory neurotransmitters are one type, whereas inhibitory neurotransmitters are another type. Nerve impulses receive communication with the help of excitatory neurotransmitters. However, the communication to the nerve impulses is blocked with inhibitory neurotransmitters.

An example of an excitatory neurotransmitter is acetylcholine. This type of neurotransmitter controls muscles as impulses are passed to the motor neurons. On the other hand, dopamine stops the transmission of nerve impulses. Therefore, the motor neurons do not receive the needed impulses. Voluntary movement is controlled by both dopamine and acetylcholine, acting together to send nerve impulses to motor neurons. In fact, mental and physiological illnesses can be caused by an imbalance of neurotransmitters. For example, the involuntary muscle spasms that are a symptom of Parkinson’s disease are caused by not...
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