Nervous System : What is it? Divisions Functions of Nervous System Neuron Neuron Types Brain Spinal Cord Peripheral Nervous System Somatic Neural System Autonomic Neural System

1. By : Priyanka

3. The nervous system is the
system that consists of brain ,
spinal cord and peripheral
nerves.
The nervous system is the
control center of our body or it
can be thought of as the body’s
communication system.

5. Communication and
coordination as it receives the
impulses, it integrate them and
take decision.
It controls muscles or
glands.(voluntary or involuntary)
It control intellectual functions.

6. Neuron
• Neuron or nerve cells
is the functional unit
of the nervous system
and are specialized to
carry "messages"
through an
electrochemical
process.
• The human brain has
approximately 100
billion neurons.
Neurons come in many
different shapes and
sizes. Some of the
smallest neurons have
cell bodies that are
only 4 microns wide.
Some of the biggest
neurons have cell
bodies that are 100
microns wide.

7. Cell body : It is the metabolic centre of the
neuron.I6t contains many organells.
Dendrites : These are the short processes that
receive and carry incoming impulses towards cell
bodies.
Axon : It is the conlike region of the cell body and
take information away from the body.
Nissn granules : These are certain granules and
important in maintaining cell shape.
Nodes of Ranvier : Gap between the Schwann
cells called nodes of ranvier.
Synapse : Each axon terminal is separated from
the next neuron by a tiny gap called synapse.
Sachwann cell
Nodes of Ranvier

8.  Neuron basic
structural and
functional unit
of the nervous
system.
 there are million
of cells in the
body…
 Unipolar
 Bipolar
 Multipolar

10. • The brain is the
central information
processing organ of
our body and acts as
control and command
system.
• It controls voluntary
movements , balance
of the body and
functioning of body
organs.
• There are three major
divisions of the brain.
They are the forebrain,
the midbrain, and the
hindbrain.

11. Brain
• Forebrain
cerebrum
diencephlon
• Midbrain
• Hindbrain
– Pones
– Medulla
– cerebellum

12. Forebrain
• There are two major divisions of
forebrain: the diencephalon and the
cerebrum.
• The diencephalon contains structures
such as the thalamus and
hypothalamus which are responsible
for such functions as motor control,
relaying sensory information, and
controlling autonomic functions.
• The cerebrum is the largest part of
brain. The forebrain is responsible
many functions i.e. receiving and
processing sensory information,
thinking, perceiving, producing and
understanding language, and
controlling motor function.

13. Midbrain
• The midbrain and the
hindbrain together make
up the brainstem. The
midbrain is the portion of
the brainstem that
connects the hindbrain
and the forebrain. This
region of the brain is
involved in auditory and
visual responses as well as
motor function.

14. Hindbrain
• The hindbrain extends from the
spinal cord . The hind brain
contains structures such as the
pons ,medulla and cerebellum.
These regions assists in
maintaining balance and
equilibrium, movement
coordination, and the conduction
of sensory information. the
medulla oblongata which is
responsible for controlling such
autonomic functions as
breathing, heart rate, and
digestion.

15. Spinal cord
• The spinal cord is a long, thin,
tubular bundle of nervous
tissue and support cells that
extends from the brain (the
medulla oblongata
specifically). The brain and
spinal cord together make up
the central nervous system.
The spinal cord begins at the
upper border of cervical 1st
vertebra and extends down to
the space between the first
and second lumbar vertebrae;
it does not extend the entire
length of the vertebral
column. It is around 45 cm
(18 in) in men and around
43 cm (17 in) long in women

16. Spinal cord• The spinal cord is protected by three layers of
tissue, called spinal meninges, that surround the
canal. The dura mater is the outermost layer, and it
forms a tough protective coating. Between the
dura mater and the surrounding bone of the
vertebrae is a space called the epidural space and
it contains a network of blood vessels. The
arachnoid mater is the middle protective layer. Its
name comes from the fact that the tissue has a
spiderweb-like appearance. The space between the
arachnoid and the underlyng pia mater is called
the subarachnoid space. The subarachnoid space
contains cerebrospinal fluid (CSF). The pia mater is
the innermost protective layer. It is very delicate
and it is tightly associated with the surface of the
spinal cord. The cord is stabilized within the dura
mater by the connecting denticulate ligaments.

17. Spinal cord
• The terminal portion of the spinal cord
is called the conus medullaris. The pia
mater continues as an extension called
the filum terminale, which anchors the
spinal cord to the coccyx. The cauda
equina (“horse’s tail”) is the name for
the collection of nerves in the vertebral
column that continue to travel through
the vertebral column below the conus
medullaris. There are 13,500,000
neurons that transmit electro-chemical
signals in the spinal cord. The cord
weighs aproximately 35 grams. The
vertebral column (bones) that supports
it is about 70 cm long and has 31
segments and 31 pairs of spinal
nerves.

18. Peripheral nervous system
The peripheral nervous system is consists of nerves .
OR
All the nerves of the body together make up the peripheral nervous
system.
It includes three types of nerves.
Spinal nerves : arises from spinal cord.(31 pairs)
Cranial nerves: arise from brain and spread throughout the
head.(12 pairs)
Visceral nerves : arise from the spinal cord and are connected to
the internal organs of the body.

19. Peripheral nervous system
Somatic neural
system
Autonomic neural
system
sympathetic
parasympathetic

20. Somatic neural system :It
relays impulses from the CNS
to the skeletal muscles.
Autonomic neural system : It
transmit impulses from the
CNS to the involuntary
organs and smooth muscles
of the body .It is self
governing nervous system.