THE-NERVOUS-SYSTEM.pdf

PRESENTATION OF GROUP:4
THE NERVOUS SYSTEM

OBJECTIVES
 IMPORTANCE OF NERVOUS SYSTEM.
 TWO MAIN PARTS OF NERVOUS
SYSTEM.
 PARTS AND FUNCTIONS
 DISEASES AND DISORDERS
 SYNOPSIS

WHAT IS NERVOUS SYSTEM?
 The nervous system is
made up of basic
units called
neurons. It is
classified as our
body‟s command
center.

 It includes the brain, spinal cord,
and a complex network of nerves.
 It also controls the growth and
development of the brain.

 Nervous tissue is made
up of nerve cells called
as neurons, whose
primary function is to
carry messages from one
body part to another.

Neurons are information
messengers. They use electrical
impulses and chemical signals to
transmit information between different
areas of the brain, and between the
brain and the rest of the nervous
system.

WHY IS IT IMPORTANT?
 It guides the everyday activities such as
waking up, automatic activities such as
breathing, and complex processes such
as thinking, reading, remembering, and
feeling different emotions. Without the
nervous system, humans would not be
able to function well.

 The human nervous system is
responsible for coordinating every
movement and action your body makes.
It controls every function inside the
human body. As well for your heart to
beat, your lungs to breath, and your feet
to walk.

Neurons help us make sense of
stimulation, control muscle
contractions, and coordinate many
bodily functions and movements.
Nervous tissue is what allows us to have
awareness, form memories, exhibit
reasoning skills and feel complex
emotions.

TWO MAIN PARTS OF NERVOUS
SYSTEM
1. CENTRAL NERVOUS SYSTEM (CNS)
2. PERIPHERAL NERVOUS SYSTEM
(PNS)

CENTRAL NERVOUS SYSTEM
(CNS)
 Made up of brain, spinal cord and
nerves inside the brain and spinal cord.
 The body‟s processing center.
 It is referred to as “central” because it
combines information from the entire body
and coordinates activity across the whole
organism.

 The brain is a complex organ that
controls thought, memory, emotion,
touch, motor skills, vision,
breathing, temperature, hunger and
every process that regulates our
body. Together, the brain and spinal cord
that extends from it make up the central
nervous system, or CNS.

3 MAIN DIVISIONS OF THE
BRAIN:
1. FOREBRAIN (PROSENCEPHALON)
2. MIDBRAIN (MESENCEPHALON)
3. HINDBRAIN (RHOMBENCEPHALON)

FOREBRAIN (PROSENCEPHALON)
 The forebrain is the biggest segment of the
brain and is located at the uppermost part of
the brain. It is responsible in all brain
functions except the automatic movements of
the brain stem. The forebrain contains the
cerebrum (cerebral cortex) which has 4
lobes and 2 hemispheres. And the limbic
system which is the emotional side of the
brain.

 The largest part of the brain, the
cerebrum initiates and coordinates
movement and regulates temperature.
Other areas of the cerebrum enable speech,
judgment, thinking and reasoning, problem-
solving, emotions and learning. Other
functions relate to vision, hearing, touch and
other senses.

2 HEMISPHERES
The cerebrum is divided into two halves:
the right and left hemispheres. They are
joined by a bundle of fibers called the
corpus callosum that transmits messages
from one side to the other. Each hemisphere
controls the opposite side of the body.

4 LOBES OF CEREBRUM
1. FRONTAL LOBE
2. PARIETAL LOBE
3. TEMPORAL LOBE
4. OCCIPITAL LOBE

1. Frontal Lobe- is located under our
forehead. It is considered as our behavior
and emotional control center and home to
our personality. Prefrontal cortex- is
part of frontal lobe behind the forehead.
This brain region has been implicated in
planning complex cognitive behavior,
personality expression, decision making,
and moderating social behavior.

2. Parietal Lobe- the parietal lobe is vital
for sensory perception and integration,
including the management of taste, hearing,
sight, touch, and smell. It is home to the
brain's primary somatic sensory cortex, a
region where the brain interprets input from
other areas of the body.

3. Temporal Lobe- sit behind the ears
and are the second largest lobe. They are
most commonly associated with processing
auditory information and with the encoding of
memory.
4. Occipital Lobe- is the visual
processing area of the brain. It is
associated with visual processing, distance
and depth perception, color determination,
object and face recognition, and memory
formation.

MIDBRAIN (MESENCEPHALON)
 The midbrain is the topmost part of the
brainstem, the connection central
between the brain and the spinal cord.
There are three main parts of the midbrain -
the colliculi, the tegmentum, and the
cerebral peduncles. involves movement of
body and head, as it provides passage
for downward pathways for the
cerebral cortex. It is a channel for the
spinal cord transmitting stimuli (sensory)
from the head and body to the direct brain.

HINDBRAIN (RHOMBENCEPHALON)
 The hindbrain is located at the back of the
head and looks like an extension of the
spinal cord. It contains the medulla, pons,
cerebellum, and brainstem. The medulla
controls the automatic processes of the
autonomic nervous system, such as
breathing, blood pressure, and heart rate.

 Nerves connect the
spinal cord to a part of
the brain called the
brainstem. The spinal
cord is an extension of
the brain.

 The brain is safely contained within the skull,
while the spinal cord is in the vertebral canal
or spine. Because they are so vitally
important, the brain and spinal cord, located
in the dorsal body cavity, are encased in a
bone for protection. The brain is in the
cranial vault, and the spinal cord is in the
vertebral canal of the vertebral column.

• The brain and spinal cord are protected
from damage by a clear liquid called
cerebrospinal fluid, 3 layers of
membranes called the meninges,
and the hard bones of the skull and
backbone.

SPINAL CORD
 The spinal cord is a long, tube-like
band of tissue. The spinal cord extends
downward from the base of your brain. Your
spinal cord carries nerve signals from your
brain to your body and vice versa. These
nerve signals help you feel sensations and
move your body. It's made up of nerve cells
and groups of nerves that carry messages
between your brain and the rest of your
body.

3 MAIN PARTS OF SPINAL CORD
1. CERVICAL (NECK)
2. THORACIC (CHEST)
3. LUMBAR (LOWER BACK)

VERTEBRAL COLUMN AND
VERTEBRAL CANAL

The tissue of the central nervous system is
made up of grey matter and white
matter. Grey matter is made up of
neurons, cells and blood vessels. White
matter is made up of axons, which are long
cords that extend from the neurons. They
are coated in myelin, which is a fatty
insulation.

 GREY MATTER
(SUBSTANTIA
GRISEA)- is made
out of cell bodies.
 WHITE MATTER
(SUBSTANTIA
ALBA)- is composed
of nerve fibers.

 The grey matter
creates a hornlike
structure throughout
the inside of the
spinal cord while the
white matter makes
up the surrounding
sections of the spinal
cord.

3 BROAD FUNCTIONS OF CNS:
1. Take in sensory information.
2. Process information.
3. Send out motor signals.
 The CNS receives sensory information from
the nervous system and controls the body's
responses.

PERIPHERAL NERVOUS SYSTEM
(PNS)
 The peripheral nervous system, which
consists of nerves that connect the brain and
spinal cord to the rest of the body. The
peripheral nerves reside outside your brain
and spinal cord. They relay information
between your brain and the rest of your body.
It plays key role in both sending information
from different areas of your body back to your
brain, as well as carrying out commands from
your brain to various parts of your body.

NERVES
Nerves are like cables that carry electrical
impulses between your brain and the rest of
your body. These impulses help you feel
sensations and move your muscles. They
also maintain certain autonomic functions
like breathing, sweating or digesting food.

We also have 43 nerves inside our body. The
cranial nerves, these are the set of 12 paired
nerves in the back of your brain. Cranial
nerves send electrical signals between your
brain, face, neck and torso. Your cranial
nerves help you taste, smell, hear and feel
sensations. They also help you make facial
expressions, blink your eyes and move your
tongue. And the nerves arising directly from
the spinal cord are called the spinal nerves.
There are 31 pairs of spinal nerves in
humans: 8 cervical, 12 thoracic, 5 lumbar, 5
sacral, and 1 coccygeal.

The peripheral nervous system is divided
into two main parts the AUTONOMIC
nervous system (ANS) which controls
involuntary bodily functions and regulates
glands. And the other one is the SOMATIC
nervous system (SNS) which controls
muscle movement and relays information
from ears, eyes and skin to the central
nervous system.

There are three types of peripheral nerves
that can be found within the two main areas
of the peripheral nervous system. These are
the sensory autonomic, and motor.
1. Sensory- it connects the brain and spinal
cord to your skin and allows you to feel
pain and other sensations.
2. Autonomic- it controls involuntary
functions like blood pressure, digestion,
and heart rate.

3. Motor- it connects the brain and spinal
cord to muscles to stimulate movement.
 When we move, the brain sends a message
to the spinal cord. From there, the nerves
carry the message to the necessary muscles
to make them contract and produce
movement. Similarly, when we touch an
object, sensory information is carried
through the nerves to the spinal cord and
then to the brain so we can make sense of
that information.

DISEASES AND DISORDERS
One of the most well know diseases of
nervous system is Alzheimer’s disease it is
the most common type of dementia. It is a
progressive disease beginning with mild
memory loss and possibly leading to loss of
the ability to carry on a conversation and
respond to environment. Alzheimer’s
disease involves parts of the brain that
control thoughts, memories, and language.

 Epilepsy is also a neurological disease which is
sometimes called a seizure disorder. A person is
diagnosed with epilepsy when they have or had
two or more seizures. Seizures are the main
sign of epilepsy, seizure is a short change in
normal brain activity it has no identifiable
cause in about half the people with these
condition. In the other half the condition may
be traced to various factors including genetic
influence. Some types of epilepsy, which are
categorized by the type of seizure you
experience or the part of the brain that is
affected or runs in the families.

Bell’s palsy, it is a condition in which it
makes a sudden weakness or paralysis on
one side of your face. It is caused by
inflammation or damage to the facial nerve.

 Cerebral palsy is a condition that affects body
movements due to brain injury. The injury can
happen before, during or after birth and does
not get worse over time. The brain damage
affects body movement and posture. It often
shows up as either floppy or stiff muscles, or
involuntary muscle movements. Cerebral palsy
can affect movement, coordination, muscle
tone and posture. It can also be associated with
impaired vision, hearing, speech, eating and
learning. And its damage to the brain is
permanent.

Aside from these diseases there are also
diseases like motor neuron disease, multiple
sclerosis, neurofibromatosis, Parkinson’s
disease, sciatica, shingles, and many more.

4 FUNCTIONS OF NERVOUS SYSTEM
1. Control of body‟s internal environment to
maintain „homeostasis‟
• An example of this is the regulation of body
temperature. As we exercise, we create heat, to
maintain a relatively constant core temperature
the nervous system sends messages to the blood
vessels to dilate or expand, it increases the blood
flow of the skin, and it increase the sweating to
help disperse the accumulating heat.

2. Programming of spinal cord reflexes
• An example of this is the stretch reflex. This
reflex functions to protect us from injury. If we
were out jogging and accidentally ran into a
pothole and rolled our ankle, the stretch reflex
would instantly sense the stretch in the muscles
around the ankle and send messages to those
muscles telling them to contract and resist the
stretch. This reflex serves to protect the ankle
from breaking and results in a minor sprain
rather than a severe break.

3. Memory and learning
• You didn’t learn to read or write overnight, did
you? A certain amount of repetition was
required to learn and memorize these key
functions. The same applies with exercise. New
movements, especially complex ones, take time
for the nervous system to learn. Remember this
when teaching new exercises to people – a
certain amount of repetition will need to occur
before their nervous system gets it right. In other
words we need to take some efforts in order
memorize or learn something.

4. Voluntary control of movement
• Every voluntary movement that a person
performs is under the direct control of the
nervous system as the nervous system sends
the messages to the body parts to move. If the
movement has been repeated numerous times
(walking for most of us…) the movement will be
very efficient. If, however the movement is new
and still requires some repetition then we
would expect the movement to be less efficient
and, in some cases, look awkward and ungainly
like for example a person learning the squat for
the first time.

SYNOPSIS
A complex network of sensory nerves, the
nervous system is one of the crucial parts of the
human body. It is responsible for reacting to
both, internal and external stimulation through
several physical actions and for carrying out
many vital body functions as well. Our nervous
system guides almost everything we do, think,
say or feel. It controls complicated processes
like movement, thought and memory. It also
plays an essential role in the things our body

does without thinking, such as breathing,
blushing and blinking. Our nervous system is
our body’s command center. Originating from
our brain, it controls our movements, thoughts
and automatic responses to the world around
us. It also controls other body systems and
processes, such as digestion, breathing and
sexual development or puberty. And in order
for us to maintain these things we must take
good care of our nervous system because this is
the most important part of our body.

THE-NERVOUS-SYSTEM.pdf

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