3. Find out what object or material is
shown in the illustration based on
its framework?
4. Why is the skeletal system very
important?
Skeletal System
- Provides the structural framework for the
body and protects internal organs such as the
heart, lungs and brain.
5. Functions of the Skeleton
1. It gives the body much-needed support.
2. It protects the internal organs in the body.
3. It makes body movement possible through
the muscles attached to them.
4. It stores important minerals like calcium.
5. It is where millions of blood cells are
produced.
10. 2 Divisions of Skeleton
1. Axial skeleton – includes
the skull, the vertebral
column, the ribs, and the
sternum.
2. Appendicular skeleton –
includes the bones of the
shoulder, arms, hands,
hips, legs, and feet.
11. Classifications of Bones
1. Long bones – are found in the limbs like arms
and legs.
2. Short bones – are found in the wrists and
ankles.
3. Flat bones – are in the shoulder blades and
skull.
4. Irregular bones – are found in face and
vertebrae.
13. Skull
- Is consists of
cranium and facial
bones.
Cranium – is made of
eight bones joint
together to form a
rigid case that
protects the brain.
14. - The face is made up of 14 facial
bones.
Eye socket – protects the eyeball.
Mandible or jawbone – protects the
teeth.
15. Spinal Column and
the Ribs
- It protects the spinal
cord, a very delicate
organ.
(A person whose spinal cord
is injured may be paralyzed.)
Neck and backbone are
made up of irregular bones
called vertebrae.
16. Vertebrae are arranged on top of the other
and move over each other slightly.
There are 33 vertebrae in the spinal
column of a child. As a child grows, the
last seven bones join together to form
just two bones.
The number of bones in the spinal column
of an adult is 26.
17. Ribs are the bones at the side of the chest.
- It protects the lungs and the heart.
- There are 12 pair of ribs.
- The upper 7 pairs are the true ribs because
they are connected to the breastbone or
sternum.
- The lower 5 pairs are called false ribs.
(The upper 3 are connected to the breastbone
and the last 2 pairs are not connected.These ribs
are called floating ribs.)
18. The shoulder has the collarbone and
shoulder bone.
Clavicle is the collarbone found in
front of the shoulder.
Scapula is the shoulder bone found at
the back of your shoulder.
20. Appendages
The lower extremities are composed
of pelvic bones that support the lower
parts of the body and aid the
movement of the legs.
Upper arm has one long bone called
the humerus and two bones in the
lower arm known as the radius and
ulna.
21. Radius or ulna is the longer of the two
bones in the human forearm.
Each wrist or carpals has 8 bones
Palm or metacarpals has 5 bones
Fingers or phalanges have 14 bones
Legs are made up of long bones.
Femur – is the upper leg and the
longest bone in the body.
22. Tibia and fibula are the two bones in
the lower leg.
Patella – is the knee bone.
Tarsals – are the anklebones (7)
Metatarsals – are the foot bones (5)
Phalanges – are the toe bones (14)
23. Bone marrow – is very important because it
manufactures the blood cells in the body. Inside
the bones are hollow spaces in which the red
blood cells are manufactured and calcium is
stored.
2 Types of Bone Marrow
1. Red bone marrow – is found in the humerus,
femur, pelvis and vertebrae.
2. Yellow bone marrow – is found in many other
bones.
24. Structure of the Bones
Bones are made up of thousands of collagen
fibers embedded in mineral salts of calcium
and phosphorus. These minerals make the
bones hard and strong.
Compact bone (outer layer) – provides strength
and protection.
Spongy bone (inner layer) – the center is less-
dense and contains a jelly-like, yellowish
substance called bone marrow.
26. Joints
- are formed where two bones meet.
- each joint is designed for a specific
movement. Except for the joint in the skull,
they can be classified according to the
movement and the shape of their parts.
27. Kinds of Joints
1. Ball and socket –
allows movement in
all directions. They
allow a person to
swing his/her arms
and legs.
- shoulder
- hips
28. 2. Hinge Joint – allows
movement in one
direction only.
- elbow
- knee
30. 4. Pivot joint – allows
rotation movement. The
joint where two bone of
lower arm, the radius
and ulna meet is a pivot
joint. This joint allows a
person to twist the
lower arm.
31. 5. Immovable (fixed)
joint – do not allow
movement. Sutures in
the skull are immovable
joint. All skull bones
except the lower jaw are
joint at sutures.
32. 1. Do regular exercises
Healthful Habits to Keep Skeletal
System Healthy
35. Evaluation:
Read each item carefully and choose the
letter of the correct answer.
1. Which is not the function of the skeletal
system?
a. It gives shape to the body.
b. It serves as framework of the body.
c. It protects the internal organs of the body.
d. It converts energy, which enables the body to
move?
36. 2. Which is the longest bone in the
body?
a. Clavicle
b. Femur
c. Humerus
d. Tibia
37. 3. Which of the following bones protect
the lungs?
a. Clavicle
b. Ribs
c. Scapula
d. Sternum
38. 4. Why is the bone marrow important to
the body?
a. It stores much fat.
b. It makes the bone strong.
c. It produces red blood cells.
d. It produces new bone cells.
39. 5. Which bone is an example of a hinge
joint?
a. Elbow
b. Hips
c. Skull
d. Wrist
