Sociology

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

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.

Neurons make up the human nervous system. They are nerve cells that process and transmit information to and from certain body parts. They send information through an electrochemical process. Neurons receive information from their neighboring cells. The chemical messages or the information is received through the dendrites. As soon as the neurons have the proper sufficient messages, a chemical reaction happens. It an electrical change called action potential. Action potentials are what we call nerve impulses. The nerve impulse travels to the axon up to its tip. Upon touch to the tip of the axon, neurotransmitters are released which sends the information to the next neuron. The site where transfer of messages happen between neurons is called the synapse. Neurons do not touch each other. Between them are synaptic cleft. It is a small gap between the end tip of the axon and the dendrites of the neighboring neurons. There must be transmission of messages through the synaptic cleft. The neuron that sends the message is referred to as the presynaptic neuron and the receiving neuron as postsynaptic neuron. In the presynaptic neuron are sacs called synaptic vesicles. The synaptic vesicles are full of neurotransmitters which are messengers of the chemical messages created through the electrochemical process to the neighboring neuron. When nerve impulses reach the end tip or the terminal buttons, synaptic vesicles free their chemicals. These chemicals are diffused through the synaptic cleft and touch the dendrite of the next neuron. The receiving neuron binds the neurotransmitter molecules with receptor sites. Special molecules located at the membrane of the receiving neuron perfectly fit these receptor sites. Since a site only accepts a certain molecule, the synapse must have terminal buttons which contains appropriate neurotransmitter and a postsynaptic membrane with corresponding receptor sites. This setup will ensure that messages are transmitted from one neuron to the other. Studies show that there are over a hundred types of neurotransmitters. Each of these neurotransmitters have unique and specific effect on nerve circuits or sites. Neurotransmitters can be excitatory and inhibitory. Excitatory neurotransmitters communicate nerve impulses or action potentials while inhibitory neurotransmitters block the transmission of messages. Level of neurotransmitters should strike a balance between its excitatory and inhibitory properties. Otherwise, this can cause harmful effects physiologically and mentally. One of the possible harmful effects of the imbalanced neurotransmitter level is the Parkinsons disease.

Part II

Refer to Ch. 2 (pp. 58-78) In Psychology An Introduction.

Write a 350- to 700-word response identifying the major regions of the brain and what functions of behavior the systems of each region control.

The major regions of the brain are the brain stem, the limbic system and the cerebral cortex.

The Brain Stem
Brain stem is situated in the portion where the spinal cord enters the brain. It is known as the central core and the most primitive part of the brain. The brain stem is composed of the medulla, the pons and the reticular activating system. The brain stem is responsible for the autonomic functions necessary to sustain life.

The medulla is located just above the spinal cord. 1.5 inches long, it controls autonomic functions such as breathing, swallowing, blood pressure and heart rate. Blinking of the eyes can also be attributed to the function of the medulla.

The pons is a structure located at the above of the medulla. The pons is responsible for sleeping, walking and dreaming. Above the pons is the reticular activating system still in the core of the brain. Reticular activating system is composed of a network of neurons which is responsible for activating the cortex and the screening of incoming messages.

The reticular activating system plays an important role in sleeping, arousal and focus. Another part of the brain is the cerebellum. It is not part of the brain stem but is located just at the back of the brain stem. The cerebellums size is comparable to a small fist. It has two hemispheres. The cerebellum is responsible for balancing and coordination of muscle movement. This part of the brain is also involved in learning of simple skills and reflexes.

The Limbic System

The Limbic System is the interconnected structure surrounding the brain stem. The limbic system is composed of the thalamus, the amygdala, the hippocampus and the hypothalamus. The limbic system is involved in the functions of memory, motives and emotions such as hunger, fear and sexual urges. Memory and fear for instance are interconnected in the functions of the limbic system. For some people, this function of the limbic system explains why frightening memories are vivid and lingering.

The thalamus is directly over the brain stem. It is composed of two structures that resemble an egg. The thalamus acts the main relay station that traffics neural transmissions between senses and the cerebral cortex which a major region of the brain. The thalamus receives messages from sensory receptors in the nervous system. The same is sent to the cerebral cortex for processing. Sensory information and messages from the lower part of the central nervous system walks through the thalamus on the way to higher brain levels. When one hears or sees something, a signal is sent to the thalamus which in turn transmits the sensory information to the brain.

Below the thalamus is the hypothalamus. This is smaller in structure compared to the thalamus. The hypothalamus is vital to survival mechanisms like hunger, emotions, thirst, sex and reproduction. It regulates temperature of the body and its autonomic nervous system. The hypothalamus has power over the endocrine system by signaling the release of hormones into the bloodstream.
Another component of the limbic system is the amygdala. It is an almond-shaped bulge. The function of the amygdala is linked to emotions such as fear, aggression and anger.
The largest component of the limbic area is the hippocampus. This component is believed to be extremely important to memory functions.

The Cerebral Cortex
The cerebral cortex is the outermost covering of the brain. Studies show that the cerebral cortex is the largest part of the brain. This is the wrinkled portion of the brain responsible for higher mental activities which is vital for learning, memory, thought and language. The convolusions are folds which fits the cerebral cortex into the skull. The cerebral cortex has two hemispheres. The two hemispheres are connected by nerve fibers known as corpus callosum. The nerve fibers are in bundles which is 4-inch long and a quarter inch thick. The nerve fibers are responsible carrying messages back and forth to and from the two hemispheres. Each hemisphere is divided into four lobes, the occipital, parietal, temporal and the frontal.

The occipital lobes are responsible for the visual processing. Meaning, it processes what people see. The parietal lobes receive sensory information from throughout the body and has somatosensory cortex. It particularly receives messages and information about pressure, pain, temperature and touch that the body experiences.

The temporal lobe regulates hearing and balance. It also has functions on emotions and motivations. The temporal lobe helps in face recognition and other complex visual processes. This lobe also has auditory functions which processes sounds heard.

Located in front of the brain and just at the back of the forehead is the frontal lobe. It is the largest lobe of the cerebral cortex. It contains the motor cortex which controls 600 muscles of the body which produce voluntary movements. The frontal lobe is also involved in short-term memory, higher mental processing, focus, initiative, problem solving and emotional control. Personality of a person may also be attributed to the function of the frontal lobe such as character, motivation, and judgments. When a person suffers from a stroke which causes damage to the frontal lobe, as common observation, the personality of the person changes. The person becomes irritable and easily agitated.

Part III

Consider the following chain of events. Describe in 350-700 words the sensory process that takes place as the scenario unfolds.

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In the scenario number 1, we can argue that the stimulus for neurons to transmit chemical messages to the brain is the information that the person is going to play baseball.  This is a mind conditioning scenario - the person is going to play baseball. With neurons and neurotransmitters at work, sending messages and transmitting messages until it reaches the brain, it knows what to expect. The person pictures a ball and the bat as associated with the baseball game. Association is one of the functions of the brain.

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In scenario number 2, the person is in the actual game. The stimulus for the neurons to trigger an electrochemical process is seeing the ball. Neurons transmit messages passed to the next neurons then to the receiving neurons until it reaches the brain through the thalamus. The nerve impulses inform the brain that through his eyes, he is seeing ball. Attention and focus functions of the brain come into play and the person knows what exactly to do as soon as the ball reaches him. Electrochemical reactions and messages will let the person know when and how to hit the ball. The movement entails muscle coordination to successfully hit the ball.

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Scenario number 3 dictates action. Originating from the neural activities that take place in the persons nervous system, the information travels rapidly along axons of the nervous system. Along the way several chemical processes has taken place transferred from one neuron to the other until it reaches the brain. Knowing the rules of baseball, the information carried by the neurotransmitters tells the brain that an action, which is to catch the ball, must be done. The transmission of message to the brain is so rapid that the person is commanded into action by the cerebral cortex of the brain which controls muscle voluntary movements.