Psychology: Structure of the Mammalian Brain, Role of Neurotransmitters, Effects of Chronic Stress

This document provides information on the structure of the mammalian brain, the role of neurotransmitters, and the effects of chronic stress. It discusses the major parts of the brain, the somatic and sympathetic nervous systems, and the HPA axis. It also explores the effects of chronic stress on the brain, body, and behavior, and provides an overview of treatments for stress.

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Question 1.
Structure of the Mammalian Brain (Abbott et al, 2010 p.11).

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A description of the major parts of the brain
Cerebellum- It is responsible for the coordination of the voluntary body movements such as
speech, posture and balance (Raji et al, 2010 p.253).
Cerebrum- It controls senses, thoughts and movements.
Hypothalamus- it regulates the metabolic activities and some other activities of the central
nervous system.
Thalamus- it is responsible for relaying sensory signals and controlling activities such as
alertness, sleep and consciousness.
Pituitary glands- The main role is to secrete hormones into the bloodstream.
Structure of the human brain (Li et al, 2011 p.76).

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Medulla- Helps in the regulation of activities such as breathing, sneezing, swallowing,
digestion and in the functioning of the heart and blood vessels (Abbott et al, 2010 p.17).
Corpus callosum- This is the part of the brain that interconnects the two hemispheres. The
sensory, motor and cognitive performances of the cerebral cortex on either side of the brain
are integrated by the corpus callosum.
Mid brain- It plays an important role in motor movement especially in the movement of the
eye and in visual processing.
Pons- Its main function is to relay messages between the cortex and the cerebellum.
Question 2.
The role of the Somatic Nervous System.
It forms part of the peripheral central nervous system and is responsible for the voluntary
movement of muscles and the reflex arc process. It consists of two types of neurons that
enable to perform this function, the sensory neurone and the motor neuron. The sensory
neuron is responsible for relaying impulses to the brain while the motor neuron relays
information from the brain to the other parts of the body (Ahmed & Ahmed, 2010 p.440). An
example of a process controlled by the somatic nervous system is the knee jerk reflex and the
blinking reflex.
The role of the Sympathetic nervous system.
The SNS is responsible for a number of process in the body, these include homeostasis,
regulation of changes to the cardiovascular system and simulation of the skeletal muscles to
contact and convert glycogen to glucose when the body perceives threat. In homeostasis, the
SNS regulates the body temperature by either changing the flow of blood to the skin or
stimulating the sweat glands to cool down the body (Ranabir & Reetu, 2011 p.18).

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The role of the Parasympathetic nervous system
While the Sympathetic Nervous system is mainly responsible for the stimulation of the
activities related to the fight or flight response, the sympathetic nervous system compliments
this by stimulating feed and breed or rest and digest activities. These are the activities that
occur when the body is at rest and more often, after eating. They include sexual arousal,
urination, salivation, lacrimation and digestion (Oslowski & Urano, 2011 p.80).
Both the parasympathetic and sympathetic nervous systems form part of the autonomic
nervous system which is also part of the peripheral nervous system and its main role is to
control several body functions such as sexual arousal, the heart rate, respiratory rate,
urination and the pupillary response (Streeter et al, 2012 p.572).
Question 3.
Role of the Neurotransmitters
Neurotransmitter Function of the transmitter and impact on behaviour.
Acetylcholine It works both as an inhibitor and an activator both in the peripheral nervous system
and in the central nervous system. In the peripheral nervous system, this transmitter
makes the skeletal muscles to contract while in the central nervous system, it plays
as a key inhibitor of the cholinergic system (Sherin & Nemeroff, 2011 p.263).
Acetylcholine therefore has an essential role in regulating the endocrine system,
learning and formation of memory and in the rapid eye movements and sleep
cycles (Jamieson et al, 2013 p.55). Since it is responsible for muscle movements,
when interfered with, it can lead to movement disruptions or even paralysis.
Noradrenalin This is a neurotransmitter that is released by the sympathetic nervous system as a
response to stress. Upon its release, it affects several behaviours in an individual.
These include arousal, reward, attention, motivation, learning, memory and in the

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modulation of vigilance (Watts et al, 2013 p.546).
Serotonin It transmits messages between several nerve cells and has several functions in the
body which include constricting the smooth muscles and generally contributing to
the wellbeing and happiness of an individual (Karlin et al, 2010 p.663). It plays a
major role in emotions, appetite, cognitive and autonomic functions. Besides, it is a
precursor of the melatonin thus it helps in the regulation of the sleep and wake
cycles of the body (Van der Oord, 2010 p.243). This hormone also plays a key role
in maintaining the mood balance.
A decrease in the level of serotonin in the blood leads to depression, violent
behaviour and a disorder in the social personality. An increased level of serotonin
on the other hand especially during the early life, leads to a violent behaviour and a
consequent aggression in adulthood (Williams et al, 2014 p.123).
Question 4.
Sources of Cortisol, adrenaline and neuropeptide and their effects (Sannibale et al, 2013
p.140).

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All the three hormones are released by the adrenal glands when the brain detects stress. They
are therefore referred to as the stress hormones. Once released, they cause the increase in the
heartbeat rate and the blood pressure which leads to flight or fight response.
Question 5.
HPA axis and the stress response.
The hypothalamic pituitary adrenal axis acts a central point for stress response system. It
intertwines the endocrine and central nervous system. The stress response process starts when
one gets exposed to or encounters a stressor. The hypothalamus releases the corticotrophin
releasing hormone. This hormone then gets bound to its receptors on the anterior pituitary
gland which results to the release of adrenocorticotropic hormone. The latter hormone then

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gets bound to its receptors on the adrenal cortex which results to the release of cortisol. After
encountering the stressor, cortisol is released for a number of hours. When a certain
concentration of the cortisol in the blood is reached, that is when the protection against the
stressor is enough, cortisol relays a negative feedback to the hypothalamus and the pituitary
gland to stop the release of the corticotrophin realising hormone and the adrenocorticotropic
hormone (Sannibale et al, 2013 p.1400). At this point, homeostasis is restored.
When an individual is continually exposed to stressors, he or she undergoes a repeated
HPA axis activation. As a result, it is therefore important to make sure that one has healthy
cortisol levels for appropriate degree of sensitivity to the cortisol’s negative feedback.
Through research, it has been identified that as one ages, the sensitivity of the hypothalamus
and the pituitary glands to the negative feedback from the cortisol reduces, and therefore
there is a subsequent rise in the respective hormones in the blood (Juster et al, 2010 p.12).
The levels also vary with gender, older men secrete less cortisol than older women while
young men produce more than young women.
Question 6.
Psychological stress
Psychological stress generally refers to the physiological and emotional reactions that an
individual undergoes when confronted by a situation that demands one to go beyond his or
her coping resources. It is created when one when an individual thinks he or she is not well
equipped to handle a particular situation. Examples of situations that can lead to
psychological stress include financial crisis, death of a loved one, marital problems and
health problems.
The worst kind of psychological stress that I have ever experienced in my life is when I
had my first break up in a romantic relationship. My fiancée whom we had been in love for

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almost three years abruptly decided to leave me and get married to another man. The basis
of her break up with me was that by then I was still financially unstable and therefore could
not afford to upkeep her. At this moment, I almost got insane. I became highly depressed, had
conflicts with almost everyone at home, lost appetite which led to a subsequent loss in weight
and also going to an extend of creating some suicidal thoughts. The situation took almost one
and a half years to heal. Looking back to this incident, I always blame myself for allowing
such a small issue to have a huge impact on me. After all, why was I to suffer because of
something that never belonged to me? I should have just let her go and find someone else to
settle with.
Question 7.
Effects of Chronic Stress.
Chronic stress has several long-term effects on the brain, body and behaviour of an
individual. These include memory loss, rapid aging in the face, and change in the personality
of the individual, weight gain and increased risks to heart attack and cancer (Li et al, 2011
p.756). The first effect of chronic stress is that it can lead to the spread of cancer throughout
the lymphatic system. When under chronic stress, the stress hormone ramps up the lymphatic
system which as a result forms basis for the spread of cancer. The chronic stress not only
increases the number of lymphatic vessels draining from a tumour but also increases the flow
of the existing ones.
Rapid aging on the face is another effect of chronic stress. Due to this stress, the eye
capillaries, being fragile, break up leading to formation dark cycles and bags under the eyes
alongside wrinkles on the forehead, around the mouth and under the eyes (Tynan et al, 2010
1060). Hair loss, adult acne and a dull dry skin are also as a result of this kind of stress. The

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dry skin comes as a result of the constant flow of cortisol which cause a dip in oestrogen and
a dull appearing skin is formed. A combination of all these lads to rapid aging on the face.
Long term exposure to chronic stress can lead to a change in the personality of an
individual especially at the work place. According to research carried out by the London
school of economics and political science, over a long period of time, one can change his or
her personality when constantly exposed to stress at the work place (Scott et al, 2012 p.20).
The research pointed out that the workers who experienced a lot of stress at the work place
showed higher levels of neocriticism. They were less extroverted, more irritable and worried.
Workers who had no stress in the work place reported desirable personality traits such as
warmth, creativity and cooperation.
Other effects of chronic stress include increased risks to cardiovascular events such as
stroke and heart attack, memory loss, weight gain and the chronic fatigue syndrome.
Exposure to a long period of stress such as staying in a difficult marriage can lead to memory
impairment which is caused by the inflammation of the immune system. Prolonged stress also
leads to a short-term memory. A stressful event such as loss of a loved one leads to an
increase in the risk of developing an irregular heartbeat, a condition known as fibrillation
which leads to an increase in the chances of developing a heart failure or heart attack.
Chronic stress can also lead to an increase in weight gain. It leads to the production of
betatrophin in the body. Betatrophin blocks adipose triglyceride lipase, an enzyme that is
responsible for breaking down the body fat thus resulting to weight gain. Chronic stress is
also responsible for the chronic fatigue syndrome. Through research, it has been identified
that the chronic fatigue syndrome is related to the imbalance in the interactions of the body’s
normal working system that aid in stress management.
Question 8.

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Treatments for stress.
Cognitive behavioural therapy.
It is a talking therapy that helps one to manage stress by changing the way one thinks or
behaves. It lays basis on the fact that feelings, physical sensations, actions and thoughts are
interconnected and that negativity in feelings and thoughts can lead to trap into the vicious
cycle (Hinwood et al, 2012 p.1450). Cognitive behavioural therapy overwhelms problems to
a positive way by first breaking the problem into smaller components. One is then shown on
how to change the negative feelings and thoughts. This type of therapy is used to treat stress
related disorders such as panic disorder, phobias, eating disorder and the stress that results
from alcohol misuse.
The use of Cognitive Behavioural Therapy in stress management has several advantages
and disadvantages. The technique is good especially when medication alone has failed to
work and its advantages include the fact that it can be completed within a very short period of
time when compared to other therapies. This therapy can also be provided in different
formats which include in groups, in apps and in self-help books. Besides, the teachings
gained here can be used in everyday life even when the treatment is over. The above merits
make it a very effective way of treating stress. Some of its disadvantages include the fact that
it is time consuming and needs some commitment in attending the training sessions, one may
experience anxiousness and discomfort since it involves confronting one’s emotions and
anxieties. Another disadvantage is that the technique mainly focuses on changing one’s
feelings, thoughts and behaviours at the expense of other potential cause of a problem such as
problems in the family which affect the well-being of an individual. Besides, the therapy only
addresses the current problems and neglects the possible causes of some mental conditions
such as unhappy childhood.

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Ecotherapy
This refers to a wide range of treatment programmes that improve the health and well-
being of an individual through the use of outdoor activities in nature. The outdoor activities
include camping, swimming, taking walks around the parks, gardening, spending time with
animals and other leisure activities. These activities help in improving depression, improving
self-esteem, lowering the blood pressure, helps in impulse control, decreases the post-
operative recovery time and encourages new positive social behaviours. This technique is
therefore vey suitable for individuals suffering from anxiety, depression and stress.
How nature treats stress is so amazing. It is believed that humans are some kind of
biologically prepared to favourably respond to nature because we evolved from it. Through
research it has been established that nature provides a quick calming effect after a stressful
event. Within around five minutes of viewing nature, the brain activity, respiration rate, blood
pressure and the production of stress hormones decreases leading to an improvement in the
moods. Besides, nature also makes one feel connected to entities beyond himself or herself
and understand the interdependencies that exist between living beings. It therefore provides a
platform where one can spiritually connect with himself or herself and with other greater
things, thus nature brings balance, calmness and connection.
Mindful Based Stress reduction.
This is a stress management programme that helps one to calm the body and the mind. It
involves teaching one on how to focus on only the things that are happening at the present
moment. It helps one to be “mindful” and pay close attention to his or her surroundings,
feelings and thoughts. For instance, one might only focus on the sounds around him or how
his clothes smells. When one is mindful, he does not only do one thing but also gives it the
full attention. This training therefore helps one to focus on the present only thus losing

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memory of the regrets in the past or worries in the future. Generally, this type of therapy
helps an individual to learn on how to control the mind so that the mind does not control you.
The mindful based stress reduction technique has been found to be successful in a number
of ways. The therapy has helped people with rheumatoid arthritis, heart disease, chronic pain,
diabetes and other problems to cope with the symptoms and better their quality of life.
Research has also established that Mindful based stress reduction has helped people to have a
better sleep, ease depression symptoms and feel less anxious. It has also aided in the
improvement of blood sugar and blood pressure problems.

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