1. Christolouka Maria – Dimitra
2. Lazaridis
Panagiotis
AEM 27065
AEM 27220
mary@med.auth.gr
panosl@med.auth.gr
BODY SYSTEM: NERVOUS SYSTEM
Student 1: Christolouka Maria - Dimitra
Question 1: How does the nervous system work?
The Nervous system is one of the seven main systems of the body. At first
the major parts of the system will be presented so that its function will be clarified
in a better way.
To start with, the basic functional unit of the nervous system is the neuron,
which is responsible for conducting neural transmission through neural impulses,
mostly to other neurons. It consists of a soma (cell body), dendrites, axons,
synapse, and myelin.
The Nervous system can be distinguished in the Central Nervous system
(CNS) and the Peripheral Nervous System (PNS). The CNS consists of the brain
and the spinal cord whereas the PNS consists of the spinal and the cranial
nerves and all of the autonomic (involuntary) distribution of nerve fibers. The
autonomic division of the PNS is further differentiated into the sympathetic and
parasympathetic components.
The most complex and delicate system of all the body system is the
nervous system. The brain is at the center of the system. The brain sends and
receives messages through a network of nerves.
This specific network of nerves allows the brain to communicate with
every part of the body. Nerves transmit information as electrical impulses from
one area of the body to another. Some nerves carry information to the brain. This
allows us to see, hear, smell, taste and touch (sensory nerves). Other nerves
carry information from the brain to the muscles to control our body's movement
(motor nerves). Generally, sympathetic fibers release norepinephrine as a
neurotransmitter whereas parasympathetic fibers release acetylcholine as a
neurotransmitter. The autonomic system supplies smooth muscles (e.g. intestine,
urinary bladder, arterioles, penis, clitoris, lungs), glands (e.g. salivary, exocrine)
and heart muscle. Often these parts of the body receive both sympathetic and
parasympathetic fibers, one of the pair may stimulate or excite and the other
inhibits or relaxes the muscle or gland. The CNS receives incoming information
from the sensory organs, interprets and processes the information, and sends
directions to skeletal muscles to contract and to glands, smooth muscles and
heart muscle. Nerves that have their origin in the brain or the spinal cord supply
the skeletal muscles. These are called motor neurons and their neurotransmitter
is acetylcholine.
What is the difference in motor and sensory nerves?
1. Function
Sensory Nerves
These send messages to the brain about how things feel. Sensory
nerves tell the brain that a stove feels hot when it is touched. Damage to
sensory nerves may result in pain or a loss of feeling.
Motor Nerves
These nerves send information about movement. When sensory nerves tell
the brain that the stove feels hot, motor nerves tell the hand to let go of the hot
stove. Damage to motor nerves causes muscle weakness.
2. Morphology
In contrast to motor nerves, some sensory neurons do not have as many
wrappings of the myelin sheath around them. Thus, they have less "membrane
resistance" and lose current by standard electrical cable properties as compared
to other sensory neurons with many wrappings.
3. Biochemical Properties
Transmitters that sensory and motor neurons use to communicate to other
neurons or muscle cells are different. There are many variations considering the
animals (invertebrates as well as vertebrates). For example, in the crayfish, the
neurotransmitter secreted from a motor neuron to communicate with a muscle is
glutamate for the excitatory motor neurons. However, crayfish also have
inhibitory motor neurons that release GABA to inhibit the muscle fiber. These
animals use mostly Ach (acetylcholine) as the neurotransmitter for their sensory
neurons. This is just the opposite way around in most of the cases for mammalsAch for motor neurons and glutamate for sensory neurons. So, there are
differences in the biochemical properties within motor and sensory neurons.
4. Proteins
There are differences in motor and sensory nerves as far as their proteins are
concerned. That is because they serve a number of different biochemical processes. On
the other hand, there may be some similar proteins that are called isoforms of proteins.
Question 2: Illustrate the nervous system that must include brain, spinal
cord and nerves.
Picture 1.
The above picture (picture 1) shows the human nervous system. We can
clearly see the location of the brain, the spinal cord and the spinal nerves on the
body. Brain and spinal cord compose the CNS. In contrast, spinal nerves consist
of one of the two divisions of the PNS. Cranial nerves, the other division, are
undistinguishable extending from the cerebrum and the brain stem. All together
consist a network. This network can be explained as similar to a road network as
it is illustrated from the picture above.
Freeway: The spinal cord is a thick bundle of nerves, which runs down the
centre of the spine.
Highways: Along the spinal cord smaller bunches of nerves branch out.
Main roads: From these bundles, smaller bundles of nerves branch out again.
Normal roads: Finally, individual nerves branch out to every part of the body.
Picture 2.
Nerves are long structures consisted of nerve fibres. Neurons accumulate
and shape nerve fibres. That means that the basic unit of them is the neuron
(picture 2). Neurons come in many shapes and sizes. There are billions of them
in a human brain. Basically they have a cell body that contains the nucleus
surrounded by cytoplasmic elements for protein synthesis and energy production.
There are two kinds of cell processes, the axon that conducts electrical impulses
away from the cell body and dendrites that are short extensions of the cytoplasm
that conduct electrical impulses toward the cell body. Because axons can be
quite long, neurons have well-developed transport systems between the nerve
cell body and axon terminals. Axons, depending on their function, may terminate
at neurons, muscles, and glands.
Question 3: Describe the function of the major parts of the brain.
1. Basic knowledge
Brain, portion of the central nervous system contained within the skull. The
brain is the control center for movement, sleep, hunger, thirst, and virtually every
other vital activity necessary to survival. The brain controls all human emotions—
including love, hate, fear, anger, elation, and sadness. It also receives and
interprets the countless signals that are sent to it from other parts of the body and
from the external environment. The brain makes us conscious, emotional, and
intelligent. The adult human brain is a 1.3-kg (3-lb) mass of pinkish-gray jellylike
tissue made up of approximately 100 billion nerve cells, or neurons; neuroglia
(means nerve glue) are smaller and 10 times more numerous than neurons.
Neuroglia function to support and protect neurons as well as containing enzymes
that can degrade neurotransmitters. This mass also contains vascular (bloodcarrying) cells and other tissues.
2. The three major parts of the brain
From the outside, the brain appears as three distinct but connected parts:
the cerebrum —two large, almost symmetrical hemispheres; the cerebellum
(“little brain”)—two smaller hemispheres located at the back of the cerebrum; and
the brain stem—a central core that gradually becomes the spinal cord, exiting the
skull through an opening at its base called the foramen magnum. Two other
major parts of the brain, the thalamus and the hypothalamus, lie in the midline
above the brain stem underneath the cerebellum.
1. Cerebrum
Here, the most high-level brain functions take place. Its two large
hemispheres make up approximately 85 percent of the brain's weight. The
exterior surface of the cerebrum, the cerebral cortex, is a convoluted, or folded,
grayish layer of cell bodies known as the gray matter. The gray matter covers an
underlying mass of fibers called the white matter. The convolutions are made up
of ridgelike bulges, known as gyri, separated by small grooves called sulci and
larger grooves called fissures. The two cerebral hemispheres are partially
separated from each other by a deep fold known as the longitudinal fissure.
Communication between the two hemispheres is through several concentrated
bundles of axons, called commissures, the largest of which is the corpus
callosum. Sulci and gyri divide the cerebrum into five lobes: the frontal, parietal,
temporal, and occipital lobes and the insula. The frontal lobe is the largest of the
five and consists of all the cortex in front of the central sulcus. Broca's area, a
part of the cortex related to speech, is located in the frontal lobe.
Information from all the sense organs is received from the cerebrum,
which sends motor commands to other parts of the brain and the rest of the
body. Motor commands are transmitted by the motor cortex, a strip of cerebral
cortex extending from side to side across the top of the cerebrum just in front of
the central sulcus. The sensory cortex, a parallel strip of cerebral cortex just in
back of the central sulcus, receives input from the sense organs. A lot of other
areas of the cerebral cortex have also been mapped according to their specific
functions, such as vision, hearing, speech, emotions, language, and other
aspects of perceiving, thinking, and remembering. Associative cortex (cortical
regions) is responsible for integrating multiple inputs, processing the information,
and carrying out complex responses.
2. Cerebellum
The cerebellum coordinates body
movements. The cerebellum provides the basis for
organizing and smoothing gestures because it
consists of a distinctive set of neural circuits well
suited to this task -- including inputs from both the
cerebral cortex and the spinal cord. Located at the
lower back of the brain beneath the occipital lobes,
the cerebellum is divided into two lateral (side-byside) lobes connected by a fingerlike bundle of white
fibers called vermis. The cerebellum coordinates
voluntary movements by fine-tuning commands from
the motor cortex in the cerebrum. The cerebellum
also maintains posture and balance by controlling
muscle tone and sensing the position of the limbs. All motor activity depends on
the cerebellum.
3. Brain Stem
The brain stem controls our most basic functions, many of which happen
without our thinking about them at all. The brain stem is evolutionarily the most
primitive part of the brain and is responsible for sustaining the basic functions of
life, such as breathing and blood pressure. It includes three main structures lying
between and below the two cerebral hemispheres—the midbrain, pons, and
medulla oblongata. There are twelve sets of cranial nerves, one of each pair for
each side of the body. Most of them originate in the brain stem. These nerves
control important things like swallowing, facial movement, the senses, and neck
and shoulder muscles. Major nerves carrying information to and from the rest of
the body pass through the brain stem. The nerve axons cross over in the medulla
so that the left side of the brain controls the right side of the body and vice versa.
Tumors on one side of the brain may well affect movement and sensation on the
opposite side of the body.
Question 4: Draw and label the three major parts of your brain.
A. Cerebrum
Picture 1: Superior cerebrum
Picture 2: Lobes of the cerebrum
B. Cerebellum
Picture 3: Cerebellum
C. Brain stem
Picture 4: The three main structures of the brain stem.
Student 2: Lazaridis Panagiotis
Question 1: Describe the five sensory organs.
Question 2: Draw and label the parts of each.
Our sensory organs take in information and send it through the nerves to
the brain for processing. Each sense collects information from the world around
us and detects changes in the body. We have five main sensory organs: The
eyes (sight), ears (hearing), nose (olfaction), tongue (taste) and skin (touch).
Each eye consists of the eyeball, which weighs 7.3-7.8 g and has a
volume of approximately 6.5cm3.
The eyeball has a number of protective features. The eyelids, eyelashes
and eyebrows are all designed to protect the eye from dirt and dust that might
enter it and cause damage. The eyeball sits inside the orbital cavity, a bony
pocket lined with fatty tissue as a cushion. Together these provide additional
protection against injury. The six extraocular muscles - 4 rectus (medial, lateral,
superior, inferior) and 2 oblique (superior, inferior) - attach at various points to the
sclera and enable the globe to move in many directions inside the orbit.
Parts of the eyeball
 Cornea
As light enters the eye, it is refracted by the cornea, a spherically curved,
transparent sturdy layer that covers the front part of the eyeball. The cornea is
the main eye’s focusing element.
 Iris
It is a circular pigmented tissue that consists of circular and radial smooth
muscle fibers arranged so as to form a doughnut shaped structure (the hole in
the middle is called the pupil) containing a stroma, itself containing the sphincter
and two layers of epithelia. The sphincter makes the pupil expand and contract,
thus regulating the intensity of light that enters the eye. The iris attaches to the
ciliary body.
 Pupil
It is the central opening of the eyeball that permits light into the interior of the eye.
 Lens
It is clear and flexible focusing element behind the pupil. Its curvature is
controlled by muscles. By changing the curvature of the lens, the eye can focus
at different "depths of field". It refracts light entering the eye and projects it onto
the retina.
 Retina
It is a photosensitive membrane lining the back of the eyeball and forming its
innermost layer. It translates the visual image into a neural signal. It terminates
the optic nerve to the photoreceptive cells, retinal receptors (known as rods and
cones), which translate the light coming into the eye into biochemical signals and
finally to nerve (electric) impulses sent back up along the optic nerve to an area
of the cortex at the back of the brain for processing. Cones -short cone-like cells
that detect colour- are less numerous than rods and are most densely
concentrated in the fovea centralis, a small depression in the center of a
yellowish area, the macula lutea, found near the center of the retina. They
become less and less dense from the fovea outward. Rods -longer cells that
respond to dim light- are absent entirely from the fovea and macula and increase
in density toward the periphery of the retina.
 Choroid
It is the middle layer of the eye and contains many blood vessels that carry
the blood supply necessary to nourish the eye’s internal structures.
 Sclera
The sclera is the white outside layer of the eye. It is made of tough fibrin
connective tissue and mainly provides protection and helps maintain the
shape of the eyeball. Both the choroid and the sclera coats consist of an anterior
and posterior portion.
Picture 1: The Structure of the Eyeball.
Each ear consists of the outer ear, middle ear and inner ear.
 Outer ear
It consists of the pinna, the external auditory canal and the outer layer of the
eardrum. Sounds are collected in the pinna and are sent through the ear canal to
the eardrum, making it vibrate.
 Middle ear
In the middle part of the ear there are three tiny joined bones (ossicles): the
malleus, joined to the inside of the eardrum, the incus and the stapes, connected
to the inner ear. Those ossicles enhance the eardrum vibrations and transmit
them into the inner ear.
The middle ear is connected to the nasopharynx of the throat through the
eustachian tube. This tube "opens" with swallowing or coughing to equalize
pressure between the middle ear and ambient pressure in the throat.
 Inner ear
The inner ear consists of fluid-filled passages called the labyrinth (cochlea).
The spiral cochlea contains microscopic liquid-hearing hair-like receptor cells that
respond to vibrations of the cochlear fluid, which are transmitted from the middle
ear. These cells activate the auditory nerve that is connected to the auditory
cortex of the brain, which finally gives meaning to the sound impulses.
The cochlea is also connected to the semicircular canals (loops that are
responsible for balance).
Picture 2: Ear Anatomy.
1. Eardrum
6. Auditory nerve
2. Malleus
7. Facial nerve
3. Incus
8. Vestibular nerve
4. Stapes
9. Cochlea
5. Semicircular canals 10. Eustachian tube
The nose is the olfactory organ and uppermost part of the respiratory
tract. Bones and plates of cartilage form the external nose, opening at nostrils,
which contain fine hairs - known as cilia - to prevent foreign objects entering. The
internal nose is a hollow structure above the roof of the mouth, divided by the
septum into two nasal cavities that extend from the nostrils to the pharynx. It
contains projecting bones called conchae (three curling plates – superior, middle
and inferior nasal concha), covered with a mucous membrane. This membrane
contains blood vessels which warm the air and tiny hair-like receptor nerve cells
that detect airborne chemicals. Activated receptor cells transmit messages to the
olfactory bulb, just above the nasal cavity. The olfactory bulb is a swelling on the
end of the olfactory nerve which carries the sensory impulses to the brain's smell
centres. These olfactory centres lie at brain's frontal lobes and limbic system,
which interpret the impulses to produce the sensation of smell.
Our sense of smell is closely associated with our sense of taste someone who is born without a functioning olfactory system has no concept of
taste as well even though they have functional taste buds. Scientists believe that
there are 50 primary odours and that we can distinguish more than 10,000
different smells.
Picture 3: Nose. 1. Nostril
2. Inferior nasal concha
3. Middle nasal concha
4. Superior nasal concha
9. Hard palate
5. Receptor nerve cells
6. Olfactory bulb
7. Olfactory nerve
8. Front lobe
10. Soft palate
The tongue is a muscular organ in the mouth, the primary organ of taste
and important in the formation of speech and in the chewing and swallowing of
food. The tongue is covered by a mucous membrane and Its upper surface,
borders and the forward part of the lower surface are free; elsewhere it is
attached to adjacent parts of the mouth. The extrinsic muscles attach the tongue
to external points, and the intrinsic muscle fibers, which run vertically,
transversely, and longitudinally, allow it great range of movement. The upper
surface is covered with small projections called papillae, which give it a rough
texture.
Taste buds are found in papillae of the tongue mucosa. Papillae come in
three types: filiform, fungiform, and circumvallate. Fungiform and circumvallate
papillae contain taste buds. Each gourd-shaped taste bud consists of three major
cell types: supporting cells which insulate the receptor, basal cells (dynamic stem
cells) and gustatory / taste cells.
There are five basic taste sensations
1. Sweet – sugars, saccharin, alcohol, and some amino acids
2. Salt – metal ions
3. Sour – hydrogen ions
4. Bitter – alkaloids such as quinine and nicotine
5. Umami – elicited by the amino acid glutamate
In order to be tasted, a chemical must be dissolved in saliva and it must contact
gustatory cells. Cranial Nerves VII and IX carry impulses from taste buds to the
solitary nucleus of the medulla. These impulses then travel to the thalamus and
from there fibres branch to the gustatory cortex (taste) as well as the
hypothalamus and limbic system (appreciation of taste).
Picture 4: The human tongue as a gustatory organ.
The skin contains more than four million sensory receptors, which are
especially concentrated in the face, back of the neck, chest, arm (upper),
fingers, soles of feet and between the legs. These nerve endings are sensitive
to touch, pressure, temperature, pain, vibrations etc. The nerve receptors
gather sensory information and relay it through specific nerve bundles back to
the central nervous system for processing and possible reaction.
This is a chart showing all of the sensory receptors in skin:
Name
Location
Function
Hair Follicle
Hairy Skin Areas
responds to hair displacement
Ending
Ruffini
Dermis of hairy and glabrous
responds to pressure on skin
Endings
skin
Krause
Lips, tongue, genitals
responds to pressure
corpuscle
Pacinian
Deep layers of demis in hairy responds to vibration sensitive at
corpuscle
and glabrous skin
150-300 Hz range
Meissner
responds to vibration sensitive at
Demis of glabrous skin
corpuscle
20-40 Hz range
different types of free nerve
Free nerve
Throughout your skin
endings respond to mechanical,
endings
thermal, or noxious stimulation
Merkel
Epidermis of glabrous skin
responds to pressure of the skin
Picture 5: Cross Section of the Human Skin.
Question 3: Name and describe three conditions associated with the
nervous system and treatments/research.
1) Depression is a complex and serious mental disorder, which has
many subtypes (major-, manic-, double-, etc.) and probably more than one
etiology. It includes a predisposition to episodic and often progressive mood
disturbances, differences in symptomatology ranging from mild to severe
symptoms, such as: (i) depressed mood (ii) loss of interest or pleasure; (iii)
significant weight or appetite alteration; (iv) insomnia or hyposomnia; (v)
psychomotor agitation or retardation; (vi) fatigue or loss of energy; (vii)
feelings of worthlessness; (viii) diminished ability to think or concentrate or
indecisiveness; and (ix) suicidal ideation.
Depression can be tackled more effectively combining medical
treatment and supportive therapy.
There has been a massive increase in the research, development and
thus effectiveness of anti-depressant drugs over the last 10 years. New drugs
have fewer side effects than more traditional medication, and are easier to
tolerate. Anti-depressants are widely acknowledged to have an effect on the
way the brain reacts to serotonin and noradrenaline – the two
neurotransmitters related to depression. Anti-depressant drugs affect the
production of neurotransmitters, their effect on the brain, or the way in which
they are broken down. There are 3 main classes of anti-depressant drugs monoamine oxidase inhibitors (MAOIs), tricyclic and tetracyclic antidepressants (TCAs) and selective serotonin re-uptake inhibitors (SSRIs).
Psychotherapy develops a new way of dealing with problems and
provides the opportunity to learn techniques that can prevent regression of
depression symptoms.
Depression is the most common mental disorder. The World Health
Organisation estimates that by the year 2020, depression will be the second
most debilitating condition in the developed world.
2) Schizophrenia is one of the most perplex and dramatic chronic
psychotic disorder which affects about 1% of the population and is roughly
equivalent for men and women. Schizophrenia has a few subtypes (paranoid,
disorganised, catatonic and undifferentiated) and includes a wide variety of
symptoms: (i) delusions, prominent hallucinations, incoherence or marked
loosening of associations, catatonic behavior, flat or grossly inappropriate
effect (two symptoms of those mentioned) (ii) bizarre delusions (iii) prominent
hallucinations of a voice with content having no apparent relation to
depression or elation or a voice keeping up a running commentary on the
person's behavior or thoughts, or two or more voices conversing with each
other. Unfortunately, there is no cure, so the medical treatment aims at the
reduction of the symptoms above. Moreover, it often has significant side
effects, such as extrapyramidal symptoms.
Today’s research mostly focuses on dopamine. The most antipsychotic drugs that are effective are dopamine antagonists that block the
brain’s utilisation of dopamine, while drugs that increase dopamine (agonists)
increase schizophrenic behaviour. However, these agents do not help many
individuals with schizophrenia, so that multiple medicines are often used
before one is found to be effective. Risperidone and clozapine belong to the
new generation medicine that is available.
3) Alzheimer’s disease (AD) is an progressive, degenerative brain
disorder that results in impaired memory, thinking and behaviour, accounting
for well over half of all cases of dementia, which is an umbrella term for
several symptoms related to a decline in thinking skills. Common symptoms
include a gradual loss of memory, problems with reasoning or judgment,
disorientation, difficulty in learning, loss of language skills, and decline in the
ability to perform routine tasks.
People with AD have abnormal deposits, or plaques, in their brain
tissue. These plaques contain beta amyloid, a protein that releases free
radicals, or highly reactive molecules that can cause damage to cells through
a process called oxidation. These free radicals are believed to lower levels of
acetylcholine and damage brain tissue, bringing on the symptoms of AD.
Currently, there is no cure for AD, but medical treatment can help to
slow the progression and improve the symptoms of the disease. The new
generation in medical treatment includes tacrine (Cognex), donepezil
(Aricept), carbamate (Exelon), memantine (Ebixa), as well as the injection
against beta amyloid.
A medical study published in the Journal of the American Medical
Association has found that high intakes of antioxidants from food may reduce
the risk of developing AD. They found that high dietary intake of vitamin C
significantly reduced the risk of developing Alzheimer’s disease and that the
reduced risk of AD from high dietary intake of vitamin E was also borderline
significant. Vitamin C is found in large amounts in citrus fruits, kiwi, and
broccoli, and good sources of vitamin E include nuts, milk, and egg yolk.
Question 4: Explain what a reflex is.
Reflexes are automatic instinctive unlearned reactions to stimuli, which are
mediated over simple nerve pathways called reflex arcs. Involuntary reflexes are
very fast, travelling in milliseconds. The fastest impulses can reach 320 miles per
hour. Reflex arcs have five essential components:
1. The receptor at the end of a sensory neuron reacts to a stimulus.
2. The sensory neuron conducts nerve impulses along an afferent pathway
towards the CNS.
3. The integration center consists of one or more synapses in the CNS.
4. A motor neuron conducts a nerve impulse along an efferent pathway from
the integration center to an effector.
5. An effector responds to the efferent impulses by contracting (if the effector
is a muscle fiber) or secreting a product (if the effector is a gland).
Reflexes can be categorised as either autonomic or somatic. Autonomic
reflexes are not subject to conscious control, are mediated by the autonomic
division of the nervous system, and usually involve the activation of smooth
muscle, cardiac muscle, and glands. Somatic reflexes involve stimulation of
skeletal muscles by the somatic division of the nervous system.
Most reflexes are polysynaptic (involving more than two neurons) and
involve the activity of interneurons (or association neurons) in the
integration center. Some reflexes; however, are monosynaptic ("one
synapse") and only involve two neurons, one sensory and one motor. Since
there is some delay in neural transmission at the synapses, the more
synapses that are encountered in a reflex pathway, the more time that is
required to effect the reflex.
Question 5: Explain what you can do to maintain a healthy nervous
system.
A healthy nervous system enables us to cope well and respond
appropriately to the countless stimuli we encounter daily. Our nervous system
can become overloaded and begin to malfunction if we do not maintain it
properly as well as “filter” excessive stimuli or stress.
An important factor to a healthy nervous system is the proper balance
of the brain’s neurotransmitters such as dopamine, GABA (gammaaminobutyric acid), and serotonin. A healthy nervous system allows us to
handle life’s ups-and-downs smoothly, and to feel more emotionally balanced.
Exercise, mental activity, stress-management techniques, proper nutrition and
diet can help to better balance the brain’s intricate chemistry.
Physical exercise is responsible for a massive release of
neuropeptides and neurotransmitters thus energising the brain and creating a
sense of well being. It leads to a much better stress hormone regulation
reducing catabolic processes and brain cell damage. It can also upgrade
cerebellar and autonomic tone improving balance, reaction time, memory,
attention and concentration span. Physical exercise on a regular basis is
therefore necessary in order to maintain a healthy nervous system.
Mental activity is a very important factor that reduces the risk of brain
damage. After all, disuse of the brain leads to atrophy, as it happens with any
other organ. Medical research has shown that people whose occupation
involves mental activity as well as the educated ones are much less likely to
suffer from a degenerative brain disease (Parkinson’s disease, Alzheimer’s
disease).
Stress is a crucial deleterious factor we must encounter in order to
prevent our nervous system from being damaged. That’s because the stress
hormone, cortisol, mediates mechanisms of brain cell death. With chronic
stress, and with age, cortisol hormone regulation breaks down leading to
higher cortisol levels which become toxic to the hippocampus, a bilateral
limbic brain structure regulating some aspects of emotion, declarative memory
and learning of new information. Hence, we should find ways to stay calm and
stress – free adopting an optimistic attitude towards life.
Last but not least, we have to follow a well-balanced diet, rich in
vitamins, minerals, antioxidants and amino acids. If possible, we should try to
avoid dietary supplements, many of which contain additional chemicals that
may cause us great harm. We should therefore prefer a healthy natural diet.
Websites consulted: (only the additional ones):
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http://hon.nucleus/nc.com/displaymonograph.php

http://pfizer.be/do/healthinfo/neuropthicpain_en.asp

http://www.d.umn.edu/~mmizuko/2230/ns.htm

http://autocww.colorado.edu/~blackmon/E64ContentFiles/AnatomyAnd
Physiology/Tongue(anatomy).html

http://freda.auyeung.net/5senses/touch.htm

http://kidshealth.org/parent/medical/body_basics/brain_nervous_syste
m.htm

http://www.50plushealth.co.uk/index.cfm?articleid=461

http://www.dialogues-cns.org/brochures/12/nn4/DCNS%2012_9.asp

http://www.health.harvard.edu/fhg/fhgupdate/B/B5.shtml#dietaryAntioxi
dants

http://psychology.okstate.edu/faculty/lmullin/lect9.ppt

http://kidb.cwru.edu/rothlab/schizophrenia%202000%20lecture.ppt

http://www.usc.edu/dept/gero/ADRC/main/dementia.html

http://www.alz.org/AboutAD/WhatIsAD.htm

http://www.umm.edu/altmed/ConsConditions/AlzheimersDiseasecc.htm
l

http://www.psychology.psych.ndsu.nodak.edu/mccourt/website/htdocs/
HomePage/Psy486/Movement%20and%20Movement%20Disorders/M
ovement%20and%20Disorders.html

http://www.gen.umn.edu/courses/1135/lab/reflexlab/reflexlab.html

http://www.rxwellnesscenter.com/Brain.asp

http://www.healthybrain.org/exercise.htm

http://www.google.com *

http://www.ntu.edu.sg/home/eopas/Image6.jpg *

http://www.tchain.com/otoneurology/images/master-ear.jpg *

http://www.sciencephoto.com *

http://www.blinn.edu/brazos/natscience/jrugila/chapt15-01.ppt *
* Source of pictures
List of Medical words
Term
neuron
Example in
Word class
context
information
Neurons sum up noun
and shape
nerve fibres
neurotransmitters
in the crayfish ,
noun
the
neurotransmitter
secreted from a
motor neuron to
communicate
with a muscle is
glutamate
brain stem
The brain stem
is evolutionarily
the most
primitive part of
the brain and is
responsible for
sustaining the
basic functions
of life…
vermis
…lobes
noun
connected by a
fingerlike bundle
of white fibers
called the
vermis.
…neuroglia
noun
(means nerve
glue) are
neuroglia
noun
Dictionary
definition
A cell
specialized to
conduct and
generate
electrical
impulses and to
carry
information from
one part of the
brain to another
Chemical
substances that
carry impulses
from one nerve
cell to another;
found in the
space (synapse)
that separates
the transmitting
neuron's
terminal (axon)
from the
receiving
neuron's
terminal
(dendrite).
A central core
that gradually
becomes the
spinal cord,
exiting the skull
through an
opening at its
base called the
foramen
magnum
Fingerlike
bundle of white
fibers which
connect the two
lateral lobes of
the cerebellum
A structure
made up from
astrocytes,
Greek
translation
νευρώνας
νευροδιαβιβαστές
εγκεφαλικό
στέλεχος
σκώληκας της
παρεγκεφαλίδας
νευρογλοία
smaller and 10
times more
numerous than
neurons.
lobe
The frontal lobe
is the largest of
the five and …
noun
gray matter
…folded,
grayish layer of
cell bodies
known as the
gray matter.
noun
dendrite
white matter
…dendrites that
are short
extensions of
the cytoplasm
The gray matter noun
covers an
underlying mass
of fibers called
the white
matter.
oligodendrocyte,
microglia that
supports nerve
tissue of the
CNS
A well-shaped
section of a
gland or an
organ
The darkercolored tissues
of the central
nervous system;
in the brain, the
gray matter
includes the
cerebral cortex,
the thalamus,
the basal
ganglia, and the
outer layers of
the cerebellum
A threadlike
extension from
a nerve cell that
serves as an
antenna to
receive
messages from
the axons of
other nerve cells
The white colored tissue of
the central
nervous system
that is paler in
color than gray
matter because
it contains nerve
fibers with large
amounts of
insulating
material
(myelin). The
white matter
does not contain
nerve cells. In
the brain, the
white matter lies
within the gray
λοβός
φαιά ουσία
δενδρίτης
λευκή ουσία
cerebellum
The cerebellum
coordinates
body
movements…
noun
cerebrum
The exterior
surface of the
cerebrum, the
cerebral cortex,
is a convoluted,
or folded,
grayish layer of
cell bodies…
noun
synapse
…consists of a
soma (cell
body),
dendrites,
axons, synapse,
and myelin.
noun
layer of the
cerebral cortex.
A large structure
consisting of
two halves
(hemispheres)
located in the
lower part of the
brain;
responsible for
the coordination
of movement
and balance.
A small
structure
consisting of
two parts
(lobes), left and
right, which form
the largest and
most developed
part of the brain;
initiation and
coordination of
all voluntary
movement take
place within the
cerebrum. The
basal ganglia
are located
immediately
below the
cerebrum.
παρεγκεφαλίδα
μετεμβρυϊκό
πρόσθιο και μέσο
εγκεφαλικό
κυστίδιο ή
ολόκληρος ο
εγκέφαλος
σύναψη
A tiny gap
between the
ends of nerve
fibres, across
which nerve
impulses pass
from one neuron
to another; at
the synapse, an
impulse causes
the release of a
neurotransmitter
, which diffuses
across the gap
and triggers an
electrical
impulse in the
next neuron.
retina
The retina
translates the
visual image
into a neural
signal.
noun
eardrum
Sounds are
collected in the
pinna and are
sent through the
ear canal to the
eardrum,
making it
vibrate.
noun
cartilage
Bones and
noun
plates of
cartilage form
the external
nose, opening
at nostrils…
Taste buds are
noun
found in papillae
of the tongue
mucosa.
taste buds
A layer of
photosensitive
cells that lines
the back of the
eyeball;
transmits
messages
involved with
vision to the
brain through
the optic nerves
Also known as
tympanic
membrane; a
sensory
structure in the
middle ear
composed of
tightly stretched
skin resembling
a drum which is
vibrated by
sound waves;
responsible for
the initial
sensory input
required for
hearing
A tough, elastic
material that
helps protect,
support and
connect body
parts
tiny structures
located on the
tongue that
distinguish sour,
sweet, salty,
and bitter tastes
and are the
initial sensory
organs involved
in taste
αμφιβληστροειδή
ς χιτώνας
οφθαλμού
τύμπανο αυτιού
χόνδρος
γευστική
απόληξη, τελικό
όργανο γεύσης
receptor
reflex
dopamine
catabolic
The nerve
receptors gather
sensory
information and
relay it through
specific nerve
bundles back to
the central
nervous
system…
Involuntary
reflexes are
very fast,
travelling in
milliseconds.
An important
factor to a
healthy nervous
system is the
proper balance
of the brain’s
neurotransmitter
s such as
dopamine, …
It leads to a
much better
stress hormone
regulation
reducing
catabolic
processes and
brain cell
damage.
noun
Specialised
cells or
structures on or
within cells that
receive specific
messages from
the environment
or other cells
υποδοχέας
noun
A rapid
involuntary
response to a
stimulus
αντανακλαστικό
noun
Α monoamine
ντοπαμίνη
neurotransmitter
found in the
brain that is
fundamental for
the normal
function of the
central nervous
system
Characterized
καταβολικός
by or promoting
destructive
metabolism
adjective
List of Academic words.
Term
portion
major
Example in
context
Brain, portion of
the central
nervous system
contained within
the skull.
Word class Dictionary
information definition
noun
A part or share
of sth larger
Two other major
parts of the
brain, the
thalamus and
noun
Μore important,
bigger or more
serious than
others of the
same type
Greek
translation
μερίδα
κύριος
the
hypothalamus,
lie in the midline
above the brain
stem
underneath the
cerebellum.
The CNS
receives
incoming
information from
the sensory
organs,
interprets and
processes the
information,
…its function
will be clarified
in a better way.
verb
Decide what the
intended
meaning of sth
is
μεταφράζω
noun (in the
context)
Work or
operation
λειτουργία
coordinate
The cerebellum
coordinates
body
movements.
verb
συγχρονίζω
accumulate
Neurons
accumulate and
shape nerve
fibres.
verb
detect
Each sense
verb
collects
information from
the world
around us and
detects changes
in the body.
Depression is a adjective
complex and
serious mental
disorder, which
has many
subtypes…
Combine,
make (various
different things)
work effectively
as a whole
Collect a large
number of
(things) over a
long period of
time or to
gradually
increase in
number or
amount
Determine,
ascertain or
discover the
existence,
presence or fact
of sb or sth
Relating to the
mind or an
intellectual
process
πνευματικός,
διανοητικός
interpret
function
mental
συσσωρεύω
εντοπίζω,
ανευρίσκω,
αναζητώ
conduct
release
A motor neuron
conducts a
nerve impulse
along an
efferent
pathway from
the integration
center to an
effector.
Physical
exercise is
responsible for
a massive
release of
neuropeptides
and
neurotransmitter
s…
verb (in the
text)
Direct the
course of sth,
manage, or
control
διεξάγω,
καθοδηγώ, δρω
ως μέσο
μεταφοράς
Noun (in the
text)
Set free from
restraint,
confinement or
bondage
απελευθερώνω,
αποδεσμεύω
Collaborative Report
Undoubtedly, all the systems of the human body are essential for the
maintenance of the homeostasis and each one is irreplaceable serving a
specific purpose. However, the nervous system has a prominent role among
the others.
First of all, the coordination of all body systems is achieved thanks to
the nervous system. The brain gathers information concerning the condition,
the proper function of all human organs, processes it and gives the necessary
orders so as to keep a balance and avoid malfunction. The nervous system
also helps us understand the world around us by means of our five senses
(sight, hearing, taste, olfaction and touch). There are numerous nerve
receptors that transform the biochemical or mechanical signals into electrical
ones so as to be sent through the nerves to the brain. Additionally, the brain
plays a major role as far as the regulation of the human body’s temperature is
concerned.
Last but not least, our nervous system is the only one among the other
body systems that differentiates us from the other mammals. Our developed
brain is responsible for the ability of humans to speak up their minds and thus
helped them create large social groups. Furthermore, our brain is gifted with
imagination, inspiration and above all ability of creation. The brain is the most
powerful “calculating tool” and nature’s most complex structure. It is
remarkable that we use only a small portion of our real potential. There are
various brain centres that control the expression of multilateral human feelings
—including love, hate, fear, anger, elation, and sadness.
On the other hand, apart from its strengths, the nervous system seems
to be rather vulnerable to many disorders. It can be damaged by:
1) vascular disorders (such as stroke, transient ischemic attack (TIA),
subarachnoid hemorrhage, subdural hemorrhage, hematoma,
extradural hemorrhage),
2) functional disorders (such as headache, epilepsy, dizziness,
neuralgia)
3) structural disorders (such as brain or spinal cord injury, Bell's palsy,
cervical spondylosis, carpal tunnel syndrome, brain or spinal cord
tumors, peripheral neuropathy, and Guillain-Barre syndrome)
4) infections (such as meningitis, encephalitis, polio, epidural
abscess),
5) degeneration (such as Parkinson's disease, multiple sclerosis,
amyotrophic lateral sclerosis (ALS), Huntington's chorea,
Alzheimer's disease).
Apart from that, unlike any other cells, the brain and nerve cells are not
regenerated. As a consequence, any damage to the nervous system is
usually permanent and is very difficult to overcome. For example, there is no
definite cure for the Alzheimer’s, a disease that involves the destruction of a
large amount of neurons. The best treatments so far (e.g. the injection against
beta amyloid) can only reduce the rate of deterioration of the disease.
What is more, the diagnosis of mental illnesses is often very difficult as
diagnostic tests (e.g. questionnaires examining basic brain functions) of that
kind can be very subjective.
It is apparent that any damage to the nervous system – even the
slightest- may unbalance the coordination of the human body systems.
Moreover, in contrast to other body systems, any damage to the nervous
system can also have physically effects as well as mentally ones. That is to
say that there is a great impact on human psychology.
It is also common for mentally retarded people to face daily prejudice.
Although great progress has been made in the fight against prejudices having
to do with physical illnesses, “racism” against people suffering from
psychological or mental problems remains.