Free Paper Sample on Components of the Nervous System

Introduction

The human brain is one of the most powerful information processing systems in the world. Scientists estimate that it contains at least 100 billion q-bits (James, 2019). The human brain consists of three major functional components, which are the hindbrain, midbrain, and forebrain. These three primary functional components work together to accomplish different tasks according to human needs. That is why it serves as the command center for the human nervous system. It receives signals from the sensory organs, processes the signals into information, and transmits the same signals to the necessary organs such muscles. The process relies on neurons that transmit information either in electrical or chemical signals. Therefore, the communication in the nervous system for the scenario provided would involve chemical and electrical signals being transmitted through the reticular activating system, Thalamus, hypothalamus, amygdala, cerebellum, somatosensory cortex, and frontal lobes.

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Neurons

They are specialized cells designed for the sole purpose of transmitting signals from the body organs to the brain and back. There are four types of neurons, which include unipolar, bipolar, pseudo-unipolar, and multipolar (Queensland Brain Institute, 2018). They are made up of cell-body, sensory receptors, and axons. The multipolar neurons have dendrites on both ends instead of sensory receptors. According to the Queensland Brain Institute (2018), for the spinal cord, there are three types of neurons. They include the sensory neurons that are the ones responsible for transmitting the input from the environment to the brain. They can be activated from either physical or chemical input. The sensory neurons are usually pseudo-unipolar. Then there are the motor neurons that connect to the muscle glands. Third, the interneurons which connect the sensory to the spinal motor neurons. They are multipolar and can, therefore, communicate with each other. Within the neuron itself, information is transmitted using an electrical charge that is conveyed along the cell membrane. However, for communication between cells, the electrical signals are usually converted into chemical signals and conveyed by neurotransmitters.

Major Functional Components of the Brain

The forebrain is the largest region and is made up of the cerebral cortex, Thalamus, and hypothalamus. As a result, the forebrain is responsible for essential functions such as reasoning, thinking, planning, as well as processing inputs such as hearing, touch, and vision. The second major component is the mid-brain, which is a small region that serves as a connection point to other parts of the brain. Finally, the hindbrain, which is located on the lower back part of the brain, is made up of parts such as pons and cerebellum. That makes the hindbrain responsible for coordinating signals and communications between brain hemispheres. It is also responsible for most of the voluntary movements.

Reticular Activating System

It is a diffuse network of nerve pathways in the brainstem that connect the spinal cord, cerebrum, cerebellum, and mediates the overall consciousness levels. According to Garcia-Rill (2009), humans have three sleep and arousal states, which are waking, asleep, and sleep and dreaming. The asleep state consists of resting, or slow-wave sleep while the sleep and dreaming state is the paradoxical, or rapid eye movement sleep. All these states are controlled by the reticular activating system (RAS), which is located in the mesopons, that interacts with the descending reticulospinal and ascending hypothalamic, basal forebrain, and thalamocortical systems (Garcia-Rill, 2009).

For example, in the real-life scenario provided, the reticular activating system would be responsible for waking Andrew. During sleep, the RAS had slowed down the brain’s electrical activity, including brain waves’ electrical voltage and the speed of neurons fire. However, that changes when the large bumblebee bumps into his leg. The RAS increases the electrical activity in Andrew’s brain hence increasing his alertness, enabling him to process information about the bee.

Thalamus and Somatosensory Cortex

The Thalamus is a brain organ between the midbrain and the cerebral cortex, responsible for relaying motor and sensory signals to the cerebral cortex. According to Sally Robertson, the Thalamus receives sensory impulses from the body as a sensation and then passes it to the cerebral cortex for interpretation (Robertson, 2019). That means that in the given scenario, the sensory impulses from receptors in his lower left leg would be received by the Thalamus, which relays the information to the somatosensory cortex of the cerebral cortex.

The thin layer of the brain covering the outer layer of the cerebrum is what is known as the cerebral cortex. The somatosensory cortex is one of the regions of the cerebral cortex that is responsible for processing sensory information, and touch sensation (Jawabri and Sharma, 2020). The sensory nerves in the left leg would receive external stimuli from the bee, making contact and convert them into internal electrical impulses. The internal electrical impulses would then be conveyed to the Thalamus, which would then determine it to be a sensory signal, and forward it to the somatosensory cortex to interpret it.

Hypothalamus, Amygdala and Frontal Lobes

The hypothalamus is located at the base of the brain, carries an increased number of functions. The hypothalamus is responsible for managing emotional responses, maintenance of daily psychological cycles, appetite control, regulating body temperature, releasing hormones, and managing sexual behavior (Pop et al., 2018). Therefore, in the scenario provided, the hypothalamus would most likely be responsible for regulating heartbeat and body temperature, depending on Andrew’s response. The hypothalamus, along with the amygdala, would determine the type of response that Andrew would have.

The amygdala is a collection of cells at the basal area of the brain that serves as the brain’s emotional center. The system is responsible for giving meaning to emotions, remembered, and attaching responses to such emotional memories. As a result, the amygdala forms an integral part of how humans process strong emotions such as fear and pleasure. That means if Andrew has ever been a similar situation, his response will depend on his previous experience. Whatever the response, the hypothalamus will address the unbalanced factors such as body temperature, blood pressure, and heart rate.

The amygdala works in tandem with the frontal lobes to manage the emotions and determine the appropriate response. The frontal lobes are responsible for thinking, decision making, reasoning, and planning. The frontal lobes are the organ that keeps the amygdala in check and prevents it from generating an automatic response of either flight or fight. When Andrew becomes aware that it is a bee that has bumped into him, the amygdala might automatically activate the flight response. However, the frontal lobes would be processing the information at the same time and determining whether the danger presented by the bee is worth flight. On the other hand, the amygdala might automatically trigger a fight response, and it would be up to the frontal lobes to gauge whether the danger presented by the bee, is small enough to justify a fight response.

Cerebellum

The cerebellum, which is located on the back and bottom section of the brain, will be responsible for coordination and movement. The cerebellum is what will enable Andrew to simultaneously use his hands to chase away the bee while moving his leg away from it. The cerebellum is responsible for coordinating physical movements. Because it is mostly involved with muscle movement, the cerebellum is also involved in eye movements. Therefore, the appropriate response determined by the frontal lobes will be transmitted to the cerebellum, which will coordinate them.

Conclusion

That means that Andrew’s bee experience would have started with the sensory neurons receiving the physical impulse of the bee bump. The signal would then rely on both electrical and chemical signals for transmission to the RAS, which would increase brain activity, causing Andrew to wake up. The sensory signals would have been received by the Thalamus, which would relay the information to the somatosensory cortex. The somatosensory cortex would relay the same information to the amygdala, and frontal lobes, which would determine the appropriate response and get the hypothalamus to regulate Andrew’s internal balance. The cerebellum would enable Andrew to carry out the flight or fight actions such as moving his leg away from the bee.

References

Garcia-Rill, E. (2009). Reticular Activating System. In Encyclopedia of neuroscience (pp. 137–143). essay, Elsevier. https://www.sciencedirect.com/topics/neuroscience/reticular-activating-system

James, G. (2019, February 19). Why Physicists Say Your Brain Might Be More Powerful Than Every Computer Combined. https://www.inc.com/geoffrey-james/why-physicists-say-your-brain-might-be-more-powerful-than-every-computer-combined.html.

Jawabri, K. H., & Sharma, S. (2020). Physiology, Cerebral Cortex Functions. StatPearls [Internet]. https://pubmed.ncbi.nlm.nih.gov/30860731/

Pop, M. G., Crivii, C., & Opincariu, I. (2018). Anatomy and Function of the Hypothalamus. Hypothalamus in Health and Diseases.
https://www.intechopen.com/online-first/anatomy-and-function-of-the-hypothalamus/

Queensland Brain Institute. (2018, March 26). Types of neurons. Queensland Brain Institute. https://qbi.uq.edu.au/brain/brain-anatomy/types-neurons.

Robertson, S. (2019, February 27). What does the Thalamus do? News Medical Life Sciences.
https://www.news-medical.net/health/What-does-the-Thalamus-do.aspx.