Download The Nervous System

By: Hugh Nguyen and Waylon Yen
THE NERVOUS
SYSTEM
Background
 The nervous system
controls and coordinates
functions throughout the
body and responds to
internal and external
stimuli.
 The basic units of the
nervous system are
neurons.
 There are 2 kinds of
nervous systems: central
nervous system and
peripheral nervous system
How It Works
 The Nervous System is a network that controls and
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coordinates all the activities
It transmits messages or signals from the brain to the
different regions of the body
It works with the help of nerves or neurons, which
conduct the signals or impulses between the two
components of the nervous system.
The neurons can be of different types, such as sensory
and motor neurons.
The sensory neurons generate and transmit the stimuli
received from the sensory organs like the eye, nose or
skin, to the central nervous system, the brain and the
spinal cord.
(Cont)
 The brain in turn processes these stimuli and sends
them back to the other parts of the body telling them
to react to a particular type of stimulus.
 The motor neurons are responsible for receiving
signals from the brain and spinal cord and
transmitting them to the other organs of the body.
 The neurons use electrochemical signals in the
transmission of signals or impulses from one neuron
to another.
Nerve Impulse
 Resting Neuron
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Outside is positive charge while
inside negative
Cell membrane pumps sodium
ions out of the cell and potassium
ions into the cell by active
transport
As a result the inside of the cell
has more potassium and fewer
sodium than the outside
The electrical charge across the
cell membrane of a neuron in its
resting state is called resting
potential
 Moving Impulse
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Neuron remains resting until it
receives stimulus
Impulse cause a movement of ions
across cell membrane
Impulse travels rapidly down axon
away from cell body and toward
axon terminals
Cell membrane thousands of
protein channels that allow ions to
pass through depending on the
“gates”
If sodium ions flow inside in the
membrane it causes the
membrane to temporarily become
more positive, reversing the
resting potential
This reverse is called action
potential
Central Nervous System
 The central nervous system
consists of the brain and
spinal cord.
 The skull and vertebrae in
spinal column protect the
brain and spinal cord.
 Cerebrospinal Fluid bathes
the brain and spinal cord
and acts as a shock
absorber that protects the
central nervous system.
Peripheral Nervous System
 Consists of all nerves and
cells not associated with
the brain and spinal cord
 Sensory division
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Transmits impulses from
sense organs to central
nervous system
 Motor division
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Transmits impulses from
central nervous to muscles
or glands
(Continued)
 Somatic Nervous System
 Regulates activities under conscious control, movement of
skeletal muscles
 Some somatic nerves involved with reflexes
 Rapid response possible because receptors in skin stimulate
sensory neurons, which carry impulses to spinal cord
 Autonomic Nervous System
 Regulates activities that are automatic or involuntary
 Control functions of the body that are not under conscious
control
Touch
 The five sensory organs are
touch, sight, hearing, taste, and
smell.
 The sense of touch is
distributed throughout the
body.
 Four kinds of touch sensations
can be identified: cold, heat,
contact, and pain.
Hearing
 The ear is the organ of
hearing. The outer ear is
away from the head and is
shaped like a cup to direct
sounds toward the
tympanic membrane,
which transmits
vibrations to the inner ear
through a series of small
bones in the middle ear
 The brain combines the
input of our two ears to
determine the direction
and distance of sounds.
Taste
 The receptors for taste, called taste buds, are situated
chiefly in the tongue, but they are also located in the roof of
the mouth and near the pharynx.
 They are able to detect four basic tastes: salty, sweet, bitter,
and sour.
 Generally, the taste buds close to the tip of the tongue are
sensitive to sweet tastes, whereas those in the back of the
tongue are sensitive to bitter tastes. The taste buds on top
and on the side of the tongue are sensitive to salty and sour
tastes. At the base of each taste bud there is a nerve that
sends the sensations to the brain.
Smell
 The nose is the organ responsible for the sense of
smell. The cavity of the nose is lined with mucous
membranes that have smell receptors connected to
the olfactory nerve.
 The smells consist of vapors of various substances.
The smell receptors interact with the molecules of
these vapors and transmit the sensations to the
brain.
Sight
 Sight or vision is the capability of the eye to focus
and detect images of
visible light on photoreceptors in the retina of each
eye that generates electrical nerve impulses for
varying colors, hues, and brightness.
 There are two types of
photoreceptors: rods and cones. Rods are very
sensitive to light, but do not distinguish colors.
Cones distinguish colors, but are less sensitive to dim
light.
Strengths
 Many neurons providing fast information to and out
of the brain.
 Able to strengthen through mental and physical
exercise.
 Humans have really complex and capable brains,
making us able to make advances through history
and differentiates us from other animals.
Weaknesses
 The many fragile neurons means the brain is very
susceptible to damage from a blow in the head.
 If one section of the brain doesn't work, most likely,
the rest of the body will suffer since the brain
controls body functions.
 Humans only use 10% of their brain power. If we
could learn to utilize the other 90%, we would be
progress a lot faster. Unfortunately, we cannot.
Diseases
Conditions associated with the nervous system
 Spinal disease is a common nervous system disease
which affects the spinal column and/or the spinal cord
and spinal nerves which are contained there in.
 Spine disease is a large area of study because of the large
number of diseases which can affect the spinal system,
from purely skeletal disorders to primary nervous system
disorders.
 All types of spine disease can present with either or both
spinal symptoms or neurological symptoms associated
with injury or compression of the spinal cord or spinal
nerves.
 To treat Spinal Disease people must have surgery.
Continued
 Epilepsy is a condition characterized by recurring
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seizures in an individual.
Seizures are an abnormal over activity of the cells of the
brain which can affect variable regions of the central
nervous system, primarily in the forebrain.
The effects of seizures depend on their location in the
brain and their extent.
The classic appearance of seizure with physical
convulsions in a patient is a common manifestation of
seizures but not all types of seizures include convulsions.
The only cure so far for Epilepsy is surgery.
Continued
 Traumatic spine disease refers to any disease of the
spine which occurs as the result of a traumatic injury
such as a fall or motor vehicle accident.
 It can include spinal fractures, traumatic disc
herniation and spinal instability.
 This causes a break down of many nerves, causing
the body to function inorderly.
 Some cures are surgery and stability of the spine.
Maintain a Healthy Nervous System
 Vitamin B Complex plays a major role in keeping
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your nervous system healthy.
Have foods which are rich in it or take vitamin
supplements if needed.
Exercise the system by writing ten minutes a day
to stimulate the sensory and motor neurons.
Various medications may be prescribed to treat these
disorders and in more severe cases, neurological
surgery may be prescribed.
Do not stress out.
THANK YOU