Nervous System
The intricate development processes that the human brain has undergone over centuries
makes it the most complex and unique system globally. Biologically, the human brain starts
developing immediately an embryo is four weeks old; it develops from the skull's base up and
outward (Ackerman, 1992). In contrast to other vertebrates, the human brain has advanced
tremendously, distinguishing humans from the rest of the vertebrates. A human being's ability to
effectively function and conduct various daily routines is achieved by coordinating different
organs of the brain; and its ability to trigger various thoughts, reactions, mobility, emotions, and
communication, through the nervous system.
Located throughout the brainstem, the Reticular Activating System (RAS) is the
component responsible for modulating the various sleep rhythms, attention, arousal, focus,
modulation of muscle tones, and response to pain (Arguinchona, 2020).
The RAS comprises connections throughout the nervous systems, which transmits sensory
information received from the spinal cord, sensory pathways, thalamus, and cortex. Four
components make up the Reticular Activating System: the locus coeruleus, raphe nuclei,
posterior tuberomammillary hypothalamus, and pedunculopontine tegmentum. Each of these
elements is unique in the neuropeptides they release. Orexin is the neuropeptide released by the
lateral hypothalamus (LH), responsible for triggering a reaction after light hits the eyes during
sleep resulting in an individual waking up (Arguinchona, 2020). Furthermore, the RAS is
responsible for muscle tones in different states of sleep; it is also the component responsible for a
human's 'fight or flight' responses in the presence of danger, leading to wakefulness.
, The thalamus components act as recipients of the information relayed by nerve cells from
four senses: sight, touch, taste, and hearing; the thalamus then relays the message to the forebrain
(Ackerman, 1992). Pain sensations, pressure, and temperature are also transmitted through the
thalamus; the nerve impulses from the cerebral hemisphere that trigger voluntary movement are
relayed through the thalamus.
Albeit its small size, the hypothalamus is the intermediary between the two major physical
control systems in the body: the nervous system and the endocrine system. The hypothalamus
plays a crucial role in identifying significant body changes, which then leads to trigger other
organs and glands to release hormones (NBIA, 2021). The generation of a 'fight or flight'
response occurs due to the hypothalamus, which acts as the brain's intermediary in interpreting
emotions into physical responses.
Also known as the 'emotion center of the brain,' the amygdala plays a crucial role by helping the
brain identify potential threats and prepare the body for a fight or flight response.
Located behind the brain stem, the cerebellum (also known as the little brain) comprises
two wrinkled hemispheres. The cerebellum coordinates and regulates voluntary limb movement,
balance, and posture; it also aids in the distinction of different textures and sounds. A healthy
cerebellum allows a person to amply coordinate limb movement in the presence of flight or fight
mode.
The human ability to consciously think and make decisions occurs as a result of the cerebral
cortex. This is the brain's wrinkled outer covering, making up more than 80% of the brain's
weight. The cerebral cortex causes human beings to make sound and informed decisions; it also
inspires the acquiring and usage of language, intricate skills for both personal and social settings
(Walinga & Stangor, n.d). The somatosensory cortex is part of the cerebral cortex, which