Transcript Nervous system

ANATOMY
NERVOUS SYSTEM
OVERVIEW
Nervous System

The nervous system
of the human is the
most highly organized
system of the body.
 The overall function of
the nervous system is
to control and
coordinate the human
body.
NERVOUS SYSTEM

The nervous system
consists of the brain,
the spinal cord and
the nerves.
 The functional,
structural unit of the
nervous system is the
nerve cell called the
neuron.
Neurons

The neuron has
extensions of various
lengths from its cell
body called Dendrites
and Axons.
 Each cell body may
have many dendrites,
but only one axon.
Neurons

The Dendrites receive
an impulse, pass it to
the cell body, then to
the axon where it is
passed on to muscle,
glands or another
neuron.
Neurons
 There
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
are three types of neurons:
Sensory
Motor or connecting
Associative
• Neurons do not connect with each other but send
impulses over spaces called synapses.
Divisions of the nervous system

The central nervous
system includes the brain
and the spinal cord. The
nerves of the spinal cord
and brain do not have the
special coating called
neurilemma which allows
nerve cells to repair.
(paralysis or death may
occur)
Nervous system divisions

The peripheral
nervous system is
composed of all the
nerves extending
from the brain (cranial
nerves) and spinal
cord. (spinal nerves)
Peripheral system

The peripheral nervous
system connects the
central nervous system to
various body structures.
Cranial nerves carry
impulses to and from the
brain, spinal nerves carry
impulses to and from the
spinal cord.
Autonomic system

The autonomic
system controls the
involuntary or
automatic activities of
vital internal organs,
such as the heart,
blood vessels and
organs of digestion.
The brain

The brain is a
complex mass of
tissue protected by
the bony structure of
the cranium. The
brain is further
protected by
membrane coverings
called the meninges
and cerebrospinal
fluid.
The brain

There are three major
parts of the brain.

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The cerebrum
The cerebellum
The brain stem
The Cerebrum

The cerebrum is the
largest part of the
brain, divided into two
hemispheres. Each
hemisphere is divided
into four lobes.

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The frontal
The parietal
The occipital
The temporal
Lobes of the brain
 Each
lobe of the cerebral hemispheres
control specific functions .

#1 The frontal lobe:
• The cells in the right half control the voluntary
motor movements of the left side of the body, and
the left side controls the right side. The frontal
lobe also controls speech.
Lobes of the brain

#2 The parietal lobe:
• This area receives and interprets nerve impulses
from the sensory receptors for pain, touch, heat
and cold. The parietal lobe also helps determine
distance, size and shape.

#3 The occipital lobe:
• Located over the back of the brain over the
cerebellum contains the visual area controlling
eyesight.
Lobes of the brain

#4 The temporal:
• Located on the sides of the brain, the temporal
lobe contains areas which control auditory hearing
and olfactory smell.
The Cerebrum

The outer layer of the
cerebrum is gray
nerve tissue called
the cerebral cortex. It
is formed with deep
folds causing
elevated portions
called convolutions
and furrows and
groves called
fissures.
The cerebrum
 This
folding (convolutions and fissures)
increase the surface area of the cerebral
cortex. The cerebral cortex controls
thoughts, judgment, memory, reasoning,
and will power.
Under the gray matter

Beneath the gray matter
of the cerebral cortex lies
the thalamus, and
hypothalamus. The
thalamus acts as a relay
center for sensory
impulses to the cerebral
cortex. The
hypothalamus controls
temperature, sleep, water
balance and chemical
activities.
The cerebellum

This part of the brain
located at the back
and lower part of the
brain coordinates the
muscular movements
of the body, such as
balance in walking
and sitting.
The brain stem

The brain stem is
made up of three
parts. The midbrain,
the pons and the
medulla. This part of
the brain controls
respiration, heart and
blood vessels.
The Spinal cord

The spinal cord is
made up of nerve
fibers protected by
the bony structure of
the vertebra and
spinal fluid. The
function of the spinal
cord is to serve as a
pathway to and from
the brain.
Diseases

Nerve cells often do
not repair themselves
so damage can cause
permanent loss of
function. Damage to
the brain and spinal
cord by force and
injury may result in
death or paralysis.
Diseases

Other disease
include:
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Parkinson's
Seizures
Multiple sclerosis
Cerebral vascular
accident (CVA or
stroke)
Infections and tumors
also may affect the
nervous system.
Vocabulary Words