The skeletal system comprises bones, cartilage, and connective structures, with major organs including the skull, ribs, and limbs. It serves essential functions such as protection of vital organs, storage of minerals and fat, movement facilitated by muscles, and blood cell formation from bone marrow. Bones are living tissues that grow and change, with joints allowing varying degrees of movement, supported by ligaments and cushioned by cartilage.

1. Bones, cartilage, and the
special structures that
connect them make up
your skeletal system

2. Major Organs of the
Major Organs of the
Skeletal System
Skeletal System
Skull Clavicle
Ribs Humerus
Radius Ulna
Patella Femur
Tibia Fibula
Pelvic Vertebral
girdle column

3. •Protection
•Storage
•Movement
•Blood Cell Formation

4. Protection
• Your heart and lungs are shielded by
your ribs
• Your spinal cord is protected by
your vertebrae
Your brain is protected
by your
skull

5. Storage
• Bones store minerals that help
the nerves and muscles function
properly
• Your arm and leg bones also
store fat that can be used for
energy

6. Movement
•Skeletal muscles pull on the
bones to produce movement
•Without bones, you
would not be able to
sit, stand, walk, or run

7. Blood Cell
Formation
•Some of your bones
are filled with a
special material
that makes blood
cells

8. •A bone may seem lifeless, but it
is a living organ made of several
different tissues.
•Bone is composed of connective
tissue and minerals that are
deposited by living cells called
osteoblasts.

9. Different Kinds of
Different Kinds of
Bone Tissue
Bone Tissue
Compact Bone
Bone tissue that does not have any visible open spaces
Spongy Bone
Bone tissue that has many open spaces
Spongy bone provides most of the strength and
support for a bone. It acts like the trusses of a
bridge.
Bone Marrow
Red marrow, found in spongy bone, produces red
blood cells
Yellow marrow, found in the central cavity of long
bones, stores fat

10. Growing Bones
Growing Bones
• Most bones start out as a soft, flexible
tissue called cartilage
• When you were born, you had little
true bone
• As you grow, the cartilage is replaced
by bone
• During childhood, growth plated of
cartilage remain in most bones,
providing a place for those bones to
continue to grow.

11. • The place where two or more bones
connect is called a joint
• Some joints allow a lot of movement,
while other joints are fixed.
• Joints that have a wide range of
movement tend to be more susceptible
to injury that those that are less
flexible.

12. Three Types of
Three Types of
Joints
Joints
• Sliding Joint
– Sliding joints allow bones in the hand to glide
over one another, giving some flexibility to the
area.
• Ball-and-Socket Joint
– Like a joystick on a computer game, the
shoulder enables your arm to move freely in all
directions.
• Hinge Joint
– Like a hinge on a door, the knee enables you to
flex and extend your lower leg.

13. Sliding
Sliding
Joint
Joint

14. Ball-and-Socket
Ball-and-Socket
Joint
Joint

15. Hinge Joint
Hinge Joint

16. • Joints are kept together with strong elastic
bands of connective tissue called ligaments.
• A strained ligament will usually heal with
time, but a torn ligament will not.
• A torn ligament must be repaired surgically
• Cartilage helps cushion the area where two
bones meet
• If cartilage wears away, the joint becomes
arthritic.