The skeleton supports the body and helps it move, and protects some internal organs. It is made up of bones that connect at joints, which can be fixed or movable depending on the type of movement allowed. Muscles contract to produce pulling forces that work with opposing muscle pairs to enable movement through antagonistic action at the joints between bones.

1. Bone and Skeleton
This Material can be found on your Science Book
pg. 34 - 37
Slide show this slide!

2. Lesson Objective
In the end of the lesson you will be able to:
• Describe the role of the skeleton
• Describe the role of joint
• Describe the principle of antagonistic muscles

3. The words that you have to be familiar with
• Skeleton : Rangka
• Joint : Sendi
• Muscle: Otot
• Antagonistic Muscle: Otot antagonis
• Lubricate: Oli/ Pelumas/Pelicin
• Skull: Tengkorak

4. The Human Skeleton
• Your skeleton supports
your body and helps it
to move
• It also protects some of
the soft organs inside
you

5. Questions A
1. List three functions of the
skeleton.
2. Look at the diagram of the
skeleton. How are the bones
in the arm (lengan) and legs
(kaki)similar?
3. As well as supporting the
body, some bones protect
other organs. Name the
bones protect: brain, heart,
and Lungs.
Answer the following questions in your
notebook or Ms. Word. Upload your
work on Google Classroom

6. • List three functions of the
skeleton.

7. 1. Look at the diagram of the
skeleton. How are the
bones in the arm (lengan)
and legs (kaki)similar?

8. 1. Name the bones protect:
brain, heart, and Lungs.

9. Joints (Sendi)
• A joint is a place where
two bones meet.
• There are two main types
of joints in our bodies:
– Fixed joints (sendi yang
tidak dapat bergerak)
– Moveable joints (sendi
yang dapat bergerak)

10. Fixed and Moveable joints
• The skull has fixed joints
in the cranium.
• Cranium is made up of
several bones.
• This helps the cranium to
protect the brain
• The jawbone is joined to
the rest of the skull by a
moveable joint
(Rahang)

11. ball-and-socket joints
• Try to move your
Shoulder!
• Your shoulder joint can
move in almost all
direction
• This is because of the
shoulder joint is a ball –
and – socket joints

12. Hinge joints
• Your elbow joint is a
hinge (read: Hinj) joint.
• It can move in only one
direction
• It moves like a door on a
hinge
elbow (siku-
Siku)
Knee
(lutut)
hinge
(engsel)

13. QUESTIONS B
• State one place in the body
where you have a fixed
joint. Why is it useful to
have a fixed joint in this
place?
• Name the bones that form
the hinge joint at your
elbow.
Answer the following questions in your
notebook or Ms. Word. Upload your
work on Google Classroom

14. • State one place in the body
where you have a fixed
joint. Why is it useful to
have a fixed joint in this
place?

15. • Name the bones that form
the ball – and – socket joint
in your shoulder.

16. • Name the bones that form
the hinge joint at your
elbow.

17. Activity 1.4
(Which kind of joint?)
• Try moving each of these joints in your body, and
decide whether each one is :
Joints in your body:
a. A finger joint
b. The knee joint
c. A toe (jempol kaki) joint
d. The hip (panggul) joint
A fixed joint A hinge joint A ball – and – socket joint
Write the answers on your note or MS. Word (it can be in the same file
from the previous work)

18. Muscle
• Muscles are organs that
help us to move.
• The diagram shows the
two main muscles in the
upper arm.
• The muscles are attached
to the bones by tendons.
• Tendons are very strong,
and they do not stretch

19. QUESTIONS C
• Name the bones that the
biceps muscles is attached
(menempel) to.
• Name the bones that the
triceps is attached to.
• ‘bi’ means ‘two’. ‘tri’ means
three. Look carefully at the
diagram and suggest why the
biceps and triceps are given
their names.
Answer the following questions in your
notebook or Ms. Word. Upload your
work on Google Classroom

20. • Name the bones that the
biceps muscles is
attached (menempel) to.

21. • Name the bones that the
triceps is attached to.

22. • ‘bi’ means ‘two’. ‘tri’ means three. Look
carefully at the diagram and suggest why
the biceps and triceps are given their
names.

23. How muscles work
• Muscle can get shorter.
This called contraction.
• When muscles contract,
they produce a pulling
force (gaya tarik).
• Look at the diagram of
the muscles in the arm.
• When the biceps muscle
contracts, it pulls on the
radius and scapula.

24. Antagonistic Muscles
• When a muscle is not
contracting, we say that it is
relaxed.
• The diagram shows what
happens when the biceps
muscle contracts and the
triceps relaxes.
• The contracting biceps
makes the arm bend at the
elbow joint.

25. • The diagram shows how
the arm can be made
straight again.
• The triceps contract
and the biceps relaxes,
it makes the arm
straighten.
Antagonistic Muscles

26. Antagonistic Muscles
• Antagonistic muscles occur
in pairs. These pairs of
muscles work against each
other to create movement.
• Triceps and biceps are an
example of a pair of
antagonistic muscles.
• As one muscle contracts
(shortens (memendek) the
other muscle relaxes
(lengthens(memanjang)).

27. summary
Copy the paragraph and choose words from the list to
complete it. Each word may be used once, more than once or
not at all.
Muscles produce a __________ force when they contract .
They can only pull. They cannot push. Muscles are joined to
bones by the________. Antagonistic muscles are a pair of
muscles working together, pulling in __________ direction.
tendons Contract
opposite pulling