Biology Essay: Central Nervous System Structure and Functionality

This essay provides a detailed overview of the central nervous system, including its structure and function, with a focus on the roles of the brain and spinal cord. It describes sensory and motor neurons, explaining how nerve impulses are transmitted through the nervous system. The essay compares voluntary and reflex actions, elucidates the role of the autonomic nervous system, and discusses the effects of nicotine on nerve impulse transmission. Key components such as the sympathetic and parasympathetic systems are explored, providing a comprehensive understanding of the nervous system's functionality. Desklib offers a range of similar solved assignments and study tools for students.

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BIOLOGY 2
Describe the structure of the Central Nervous System
The central nervous system is usually accountable for incorporating sensory details along
with retaliating appropriately. However, it usually entail two elements that the spinal cord and
the brain which typically works together to send messages between one another. The spinal cord
normally represents the passage for signals between the brain and the rest of the body.
Furthermore, it manages simple musculoskeletal reflexes with no intake from the brain. On the
other hand, the brain is answerable for amalgamating most sensory details together with
synchronizing the operations of the body both sensibly and insensibly (Bernard-Marissal, Chrast,
and Schneider, 2018).
The brain happens to be the most complex organ since is it’s the central control module
of the body and synchronizes all the body operations. From bodily passage to the organic process
of hormones, the generation of memories together with the perception of feelings.
Figure 1 (Shen and Zipes, 2014)
The spinal cord usually conveys details amidst the brain and the body together with the
other escapades. It is however linked to a portion of the brain known as brainstem which passes
via the spinal canal ( (Zipes 2014)). The cranial nerves usually depart the brainstem while the
nerve roots leave the spinal cord to both sides of the body.
Describe the structure of the Sensory connector and motor neurons.

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The sensory neuron usually alerts the rest of the brain concerning the external and
internal surrounding by handling details which is extracted from one among the five senses
(Shen and Zipes, 2014). Accordingly, they usually receive data from the sense organs to the
brain and the spinal cord. They have elongated dendrites and tiny axons.
Figure 2 (Shen and Zipes, 2014)
The motor neurons typically convey the electrical instincts off from the brain and the
spinal cord to the organs and muscles within the body. It has short dendrites and long axons
Figure 3 (Scott, Cluff, Lowrey and Takei, 2015)
You should describe how nerve impulses are transmitted
The nerve impulses are the electrical current which moves via the nerve cell that is controlled to
the nervous system that will ultimately generate a report. The report is however handled within
the brain for specific reaction (Scott, Cluff, Lowrey and Takei, 2015). The conveyance of the
nerve impulse usually begins with energizing of a nerve cell by modifying the voltage across the

BIOLOGY 4
wall of the axon of the nerve cell. The alteration in voltage is because of change of charges. The
membrane of an inactivated neuron is usually modified that is there are differences in the
electrical charges amidst inside and outside of the membrane (Chappell and Payne, 2016).
The polarization is usually developed through retaining a surplus of sodium ions on the
out part and surplus of potassium ions on the inner side. Particular quantity of these ions usually
leeks across the membrane through leakage channels (Kumar, Singh and Baleanu, 2018). There
is typically an electrochemical gradient created that is essential for an act possible to be
produced. When there is a stimulus, this results to the sodium media situated on the surface of
the axon to open thus generating an influx of sodium into the axon. As a result, there is usually a
charge inside the axon to converse and develop into definite, a procedure which is known as
depolarization.
The primary augmentation of the resting possibility is the dissimilarity in penetrability of
the resting membrane to potassium ions against sodium ions. The resting potential is the
inactivated polarized condition of a neuron while the graded possibility is a charge within the
resting potential of the plasma membrane in retaliation to a stimulus. Once the AP is induced, it
moves in one route from the soma to the axon terminals (Nieuwenhuys, Hans and Nicholson,
2014). Once it crosses a particular region of an axon, that section has to go back to its resting
condition which is known as repolarization. Within this duration, the sodium ion media which
were formerly unlocked throughout depolarization begin to shut steadily and concurrently the
potassium ion media unroll which causes efflux of potassium ions from inside the axon.
Usually, there exists a technique which is known as sodium-potassium pump that
continually operates through forcing three sodium ions out for each two potassium ions being

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pushed in and hence retaining together with reinstating the axon back to its resting potential.
You should compare voluntary and reflex actions.
The reflex action is the unintended act which in reply to instinct generated by a stimulus.
On the other hand, the intended acts are retaliations to stimuli which are sensibly directed by the
brain (Nieuwenhuys, Hans and Nicholson, 2014). The voluntary actions are usually initiated in
mind because of thinking while the reflex actions are typically initiated by the stimulation of
receptors such as skin. Accordingly, the involuntary response the instinct move to the motor
section and hence down to the spinal cord while the reflex action impulses pass up dendrite and
axon of a sensory neuron and on to relay neuron. Last but not least, involuntary action, there are
many cells and synapses together with longer pathways, therefore, making it slow while on the
reflex actions, only three to two synapses are available which makes it quicker.
You should explain the role of the autonomic nervous system.
The autonomic nervous system is usually liable for restricting unconscious body
operations like heartbeat, flow of blood, digestion and breathing (Le Bars, Hsu, and Waszak,
2016). It usually has three parts that are a sympathetic system, parasympathetic system, along
with the enteric nervous system.
Figure 4 (Klingseisen and Lyons, 2018)

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Accordingly, it typically operates by getting information environment along with other
body parts where sympathetic and parasympathetic systems gravitate antagonizing operations.
The effects of Nicotine on the transmission of nerve impulses
Nicotine is usually derived from the tobacco plant and generally highly addictive.
However, it often increases pressure and heart pulse, contraction of the arteries along with
provocation of the central nervous system. Furthermore, it usually activates the receptors once in
the brain known as cholinergic receptors that are plentiful in other body parts of the body like
muscles, heart, adrenal glands (Klingseisen and Lyons, 2018). In that case, it infiltrates the brain
and disturbs its usual operation. It also triggers the emancipation of several neurotransmitters like
dopamine which is answerable for feelings of contentment.

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Bibliography
Bernard-Marissal, N., Christ, R. and Schneider, B.L., 2018. Endoplasmic reticulum and
mitochondria in diseases of the motor and sensory neurons: a broken relationship?. Cell death &
disease, 9(3), p.333.
Chappell, M. and Payne, S., 2016. The Central Nervous System. In Physiology for
Engineers (pp. 129-139). Springer, Cham.
Klingseisen, A. and Lyons, D.A., 2018. Axonal regulation of central nervous system
myelination: structure and function. The Neuroscientist, 24(1), pp.7-21.
Kumar, D., Singh, J., and Baleanu, D., 2018. A new numerical algorithm for fractional Fitzhugh–
Nagumo equation arising in the transmission of nerve impulses. Nonlinear Dynamics, 91(1),
pp.307-317.
Le Bars, S., Hsu, Y.F. and Waszak, F., 2016. The impact of subliminal effect images involuntary
vs. stimulus-driven actions. Cognition, 156, pp.6-15.
Nieuwenhuys, R., Hans, J. and Nicholson, C., 2014. The central nervous system of vertebrates.
Springer.
Scott, S.H., Cluff, T., Lowrey, C.R. and Takei, T., 2015. Feedback control during voluntary
motor actions. Current opinion in neurobiology, 33, pp.85-94.
Shen, M.J. and Zipes, D.P., 2014. Role of the autonomic nervous system in modulating cardiac
arrhythmias. Circulation research, 114(6), pp.1004-1021.