Lesson 2
The Bones and Muscles of Our Body
Let us start our lesson today with an activity.
All children please stand up. First of all, touch your
arm gently and then press it a little.
What difference have you experienced in the two activities?
When we touch the arm gently, it feels soft and when we
press it, we feel something hard inside.
What are the soft part and the hard part called?
The soft part under the skin is called the muscle. The
hard part is called the bone.
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Now, each child will touch different parts of her/his
body to feel bones and muscles.
What have we found on touching different parts of our
body?
Most parts of our body have both bones and muscles.
Some parts like ear lobes, lips and eyelids, have
muscles only.
We have a skeleton made of bones in our
body. We can see it in the picture. It is called
the skeletal system.
What is the significance of the skeletal
system in our body?
The sketetal system
gives shape to our body.
protects our internal organs.
Let us now learn about some bones
of our body.
We have many bones from our head
to toe in our body.
Skeletal System
Do you know that there are 206 bones in the
body of an adult? The biggest bone of our
body is called femur which is located in the
thigh. The smallest bone is called stapes. It
is located in the middle ear.
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The bones of the head make
our skull. There are two types of
bones in our skull. The first
group of bones make the brain
box. It protects our brain.
In the second group, we have
bones of our forehead, temples,
cheeks, nose, jaws and the
bones around the eyes. These
bones protect the organs present
in them.
Let us do an activity
All the children will stand in a circle. Now touch the back
of the child in front of you starting from the neck. Move
your hand downwards.
What do you feel?
When we touch the middle part of our back
from the neck downwards, we find it hard.
This is the spine or the backbone of our
body.
Let us look at the picture alongside
showing the spine.
The spine is made up of small bones,
each is called a vertebra.
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Do you know that the brain and
the spinal cord control all the
functions of our body?
Our brain is enclosed in our
skull. It is protected by the brain
box. The spinal cord is like a rope
emerging from our brain. Many
nerves coming out of the spinal
cord are spread throughout the
body. The spinal cord is protected
by a tube-like structure formed
by the vertebral column. The
brain and the spinal cord are the
main parts of the nervous system.
Brain
Skull
Spinal
cord
Nerve
The backbone gives elasticity to our body.
We can bend our body forward or backward or to the
left or to the right, due to our backbone.
Have you now understood the
importance of backbone in our
body?
To keep our backbone
healthy, it is important to
maintain a correct posture
while sitting or standing.
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Look at the picture of these bones.
Which part of the body do they belong to?
These bones are located in our chest.
These bones are called ribs. Ribs protect
the internal organs located in our chest.
There are twelve pairs of ribs in our body.
These ribs are joined with the chest bone
in the front and backbone on the back.
Ribs
Which internal organs of our body do the chest bones
protect? Write the answer below.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
upper
arm
Let us now know about the bones of our
arms and legs.
We have one bone in the upper part of our
arm above the elbow. There are two bones in
the lower part, below the elbow.
The upper bone is joined to
the shoulder bone.
Our wrist, palm and fingers
have a number of small bones.
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lower
arm
Touch your hand and find out:
How many bones are there in each of your finger? _________
How many bones are there in your thumb? __________
The bone of the part of your legs above
the knee is called femur – the thigh bone.
Femur bone is the longest and the
strongest bone of the body. It is joined to
the hip bone.
Femur
(Thigh
bone)
The part of the leg below the knee has
two bones.
Do you know that bones of our legs
support the weight of our body?
Touch and find out.
Like our fingers,
our toes are also
made up of small
bones.
How many bones are there
in your big toe? __________
How many bones are there
in the toes of the feet?
__________
Let us do an activity
Stand straight. Try to move one of your arms in a circular
motion without bending it. Can you do so?
Now try to bend your arm below the elbow and turn
it around.
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What is the difference in these two movements?
The movement of our arm in a circular motion can only be
from the point where the bones of the shoulder and the upper
arm join.
However, from the elbow we cannot move our forearm
in this manner.
Do you know how it is possible to make circular movement
of our arms?
This is possible because our arm bone is attached to the
shoulder bone in a special way. The place where two bones
join is called a joint.
There are different types
ball and socket joint
of joints in our body. That
is why, different parts of the
body
have
different
movements. You have
already experienced it while
doing the activity.
The kind of joint, that
allows any part of our body
to move in all directions is
called a ball and socket
joint. The arm and shoulder
hinge joint
joint as well as the thigh and
hip joint are examples
of that.
In the case of elbow and
knee joints, the bones can
move only in one direction.
Such a joint is called the
hinge joint.
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Do you know how bones are able to move?
The muscles in our body make it possible for
the bones to move. Muscles are attached to
all bones in our body. They help in the
movement of our body.
We can move some parts of our body,
like hands and legs, as and when we want.
This is because the muscles in these parts
function as and when we want.
These muscles are called
voluntary muscles.
There are certain parts of our body whose
movement is not in our control, for example,
foodpipe, windpipe, heart, etc. These muscles
are called involuntary muscles.
In this lesson We Have Learnt
The skeletal system gives shape to our body and protects our
internal organs.
An adult has 206 bones.
The place where two bones meet is called a joint.
There are different kinds of joints in our body which help in
different kinds of movements.
Muscles which function as per our will are called voluntary
muscles.
Some of the muscles which do not function as per our will
are called involuntary muscles.
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What Have We Learnt ?
I.
ORAL WORK
1.
Which bones of our body protect our heart and lungs?
2.
How many bones are there in the fingers of both hands?
3.
Which is the longest and the strongest bone of the body?
4.
What kind of muscles is the heart made of ?
5.
What is a joint?
II.
WRITTEN
1.
What is the difference between bones and muscles? Give one
example of each.
2.
Which is the smallest bone in the body? In which part is it located?
3.
What is the difference between voluntary and involuntary muscles?
Give one example of each.
4.
What is the importance of the skeletal system for our body?
5.
What is the significance of joints in our body?
6.
Each of the following questions has four possible answers.
Mark (9) the most suitable answer.
(i) By using the shoulder joint
(a) we can move the arm in all directions.
(b) we can move the arm only to the right and to the left.
(c) we can move the arm only in the right direction.
(d) we can move the arm only in the left direction.
(ii) Hands and legs have
(a) voluntary muscles.
(b) involuntary muscles.
(c) both voluntary and involuntary muscles.
(d) none of these.
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III.
THINGS TO DO
•
Move those parts of your body where you have
joints. Find out where you have ball and socket
joints and hinge joints.
•
Wet your feet. Place your feet on the ground and
see the shape of your footprint. If your footprint
is flat, inform your parents and the teacher.
Consult a doctor about it.
•
Draw a picture of the ball and socket joint.
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