Neuron &
Nerve
Impulse
BIOLOGY
STANDARD X
PREPARED BY
JINCY JOY
| NEURONS & NERVE IMPULSE PAGE | 02
NATIONAL ANTHEM
Jana-gana-mana-adhinayaka jaya he
Bharata-bhagya-vidhata PanjabaSindhu-
Gujarata-MarathaDravidaUtkala-
BangaVindhya-HimachalaYamuna-
Gangauchchala-jaladhitarangaTava
Subha name jage,tava
subha asisa mage,gahe tava
jayagatha.Jana-gana-mangala-dayaka
jaya heBharata-bhagya-vidhata.Jaya
he, Jaya he, Jaya he,jaya jaya jaya
jaya he.
PLEDGE
India is my country and all Indians are my
brothers and sisters. I love my country and
I am proud of its rich and varied heritage. I
shall always strive to be worthy of it. I
shall give respect to my parents, teachers,
NEURONS & and elders and treat everyone with
courtesy. To my country and my people, I
pledge my devotion. In their well-being
NERVE and prosperity alone, lies my happiness.
IMPULSE
| NEURONS & NERVE IMPULSE PAGE | 03
Certain icons are used in this
textbook for convenience
For further reading (Evaluation not required)
Activities
Assessment
Extended activities
PAGE | 04
Neurons &
Nerve Impulse
Observe the image and identify the sense organs and their
response
Nose- smell
Ear- hear
Our sense organs detect changes in the world around us known
as stimuli.
PAGE | 05 NEURON & NERVE IMPULSE|
Complete the chart 1.0 given below which shows the stimuli which
cause receptor cells in the sense organs to produce impulses.
Sense Organ Stimulus
Skin Temperature,
Pressure & Pain
Tongue Chemical
tastes(in food &
Nose
drink)
Eye
Ear
Chart 1.0
How does the nervous system help us
respond?
The sense organs contain groups of
specialized cells called receptor cells which
produce electrical impulses in response to
specific stimuli. The nervous system must
receive and process information about the
world outside in order to react, communicate,
and keep the body healthy and safe.
Observe the illustration 1.1 and write down a
note on the structure and functions of
nervous system
Illustration 1.1
Structure of the nervous system
PAGE | 06 NEURON & NERVE IMPULSE|
A neuron is a nerve cell that is the basic building block of the
nervous system.
Neurons are similar to other cells in the human body in a number of
ways, but there is one key difference between neurons and other
cells. Neurons are specialized to transmit information throughout
the body.
Complete the chart 1.1 given below and find out the similarities
Between Neurons and Other Body Cells and the difference that
make neurons unique
Similarities Between Differences That Make
Neurons and Other Body Neurons Unique
Cells
Neurons have a
Neurons and other body cells membrane featuring an
both contain a nucleus that axon and dendrites,
holds genetic information. specialized structures
designed to transmit
and receive information.
Chart 1.1
Structure of neuron
The primary components of the neuron are the soma (cell body),
the axon (a long slender projection that conducts electrical
impulses away from the cell body), dendrites (tree-like structures
that receive messages from other neurons), and synapses
(specialized junctions between neurons)
PAGE | 07 NEURON & NERVE IMPULSE|
However, all neurons vary somewhat in size, shape, and
characteristics depending on the function and role of the neuron.
Analyze the illustration 1.2 given below and write a note on the main
parts of the neuron and their functions.
Illustration 1.2
Structure of neuron
Longest Axon
The longest axon in the
human body extends from
the bottom of the spine to
the big toe and averages a
length of approximately
three feet!
PAGE | 08 NEURON & NERVE IMPULSE|
Some axons are covered with myelin, a fatty material that wraps
around the axon to form the myelin sheath. This external coating
functions as insulation to minimize the dissipation of the electrical
signal as it travels down the axon.
Illustration 1.3
The neuron diagram also shows the oligodendrocyte,
myelin sheath, and nodes of Ranvier.
Myelin is produced by glial cells, which are non-neuronal cells that
provide support for the nervous system. In the central nervous
system, the glial cells that form the myelin sheath are called
oligodendrocytes; in the peripheral nervous system, they are called
Schwann cells.
Analyze the illustration 1.3 and write down the functions of myelin
sheath and glial cells.
PAGE | 09 NEURON & NERVE IMPULSE|
Functions of Neuron
neurons transmit signals in the form of
electric impulses from the brain to the
body and back. Individually, neurons
can pass a signal all the way from their
own dendrites to their own axon
terminals; but at a higher level, neurons
are organized in long chains, allowing
them to pass signals very quickly from
one to the other.
Illustration 1.4
The neuron chain
One neuron’s axon will connect chemically to another neuron’s
dendrite at the synapse between them.
Illustration 1.5
Diagram showing the general process of synaptic
transmission.
PAGE | 10 NEURON & NERVE IMPULSE|
Analyze the illustration 1.6 and with the help of the indicators and
your teacher write down a short note on the generation of nerve
impulse
Illustration 1.6
Diagrom showing impulse transmission
Indicators
Charges on either side of the plasma membrane.
Change in the charges of ions when stimulated.
Transmission of a nerve impulse.
Electrically charged chemicals flow from the first neuron’s axon to
the second neuron’s dendrite, and that signal will then flow from
the second neuron’s dendrite, down its axon, across a synapse, into
a third neuron’s dendrites, and so on.
PAGE | 11 NEURON & NERVE IMPULSE|
Types of Neurons
There are three major types of neurons: sensory neurons, motor
neurons, and interneurons. All three have different functions, but
the brain needs all of them to communicate effectively with the rest
of the body (and vice versa).
Analyze the illustration 1.7 and prepare a table on the difference
between sensory and motor neurons
Sensory Neuron Motor Neuron
Neurons that carry sensory A neuron that carries motor
impulse from sensory organs impulses from the central
to the central nervous system nervous system to specific
are known as sensory neurons effectors is known as motor
neurons.
Illustration 1.7
Interneurons
Types of neurons
Interneurons are neither
sensory nor motor;
rather, they act as the
“middle men” that form
connections between the
other two types.
PAGE | 12 NEURON & NERVE IMPULSE|
Assessment
Draw the diagram and label the following parts
The part which secretes acetylcholine.
The part which receives impulses from the adjacent neuron.
The part which carries impulses from the cell body to the
outside.
Identify the word pair relationship and fill in the blanks
Sensory nerves: Carries impulses to the spinal cord .………….. :
Carries impulses from the brain to various parts of the body
Dendrite: Receives impulses…………… : Carries impulses outside.
Extended Activities
1. Construct a model of a neuron using suitable scrap
materials and exhibit in the class
PAGE | 13 NEURON & NERVE IMPULSE|
Notes
