1. SKELETAL
SYSTEM

2. The skeletal system contains bones
as well as other structures that
connect and protect the bones and
that support other functions in the
body.
Skeletal System

3. •Bones support your body.
•They help you sit up and stand.
•They make it possible for you to
lift your legs to walk up stairs.
Support
Functions

4. •Different parts of your body can
move in different ways because of
your skeletal system.
•Your knee bends when you kick a
soccer ball.
•Bones can move because they are
attached to muscles.
•Your skeletal system and your
muscular system work together
and move your body.
Movement
Functions

5. •The skull protects the soft tissue
of your brain from damage.
•Other bones help protect your
spinal cord, heart, lungs, and
other organs in your body.
Protection
Functions

6. •Make and store materials needed by
your body.
•Red blood cells are produced inside
some of your bones.
•Bones also store fat and calcium.
Calcium is a mineral needed for
strong bones. It is also used in many
other cellular processes. When the
body needs calcium, it is released
from the bones into the blood.
Production and Storage
Functions

7. A bone is an organ made of living tissue.
Structure of Bone

8. Structure of Bone
There are two main types of bone tissue:
compact bone & spongy bone.

9. Compact Bone
The hard, outer area of long bones is
made up mostly of compact bone tissue.
This tissue is a thick, dense web of fibers.

10. Spongy Bone
Spongy bone tissue is located near the
ends of long bones.

11. The small holes in spongy bone tissue
make it look like a sponge.
Spongy Bone

12. Because of these holes, spongy
bone tissue is not as dense as
compact bone tissue.
Spongy Bone

13. Spongy Bone
A short bone, such as
the one in your wrist, is
mostly spongy bone
tissue.

14. The inside of most bones is made up of a soft
tissue called bone marrow.
Marrow

15. •There are two types of bone marrow.
•Red bone marrow is the tissue where red blood
cells are made.
•It is found in the spongy ends of long bones
and in some flat bones, such as the ribs.
Marrow

16. How long does it take to produce 2-3 million red
blood cells?
Marrow
1 Second!

17. •Yellow bone marrow stores fat.
•Yellow bone marrow is found in the longest
part of long bones.
Marrow

18. The strong, flexible tissue that covers the ends
of bones is called cartilage.
Cartilage

19. •Cartilage keeps the surfaces of bones from
rubbing against each other.
•It protects bones and reduces friction in joints.
Cartilage

20. Cartilage

21. •The parts of a bone that are not covered by
cartilage are covered by periosteum.
•The periosteum is a membrane that surrounds
bone.
Periosteum

22. •This thin tissue has blood vessels, nerves, and
cells that make new bone tissue.
•It helps bones function and grow properly.
•It also helps a bone heal after an injury.
Periosteum

23. Periosteum

24. Before you were born, your skeleton was
made mostly of cartilage.
Periosteum

25. During infancy and childhood, the cartilage
was slowly replaced by bone.
Formation of Bones

26. The long bones in your body, such as the
bones in your legs and arms, have areas of
growth that produce new bone cells.
Formation of Bones

27. These areas are called growth plates.
Formation of Bones

28. Growth plates produce cartilage that is then
replaced by bone tissue.
Formation of Bones

29. A growth plate is the weakest part of an
adolescent bone.
Formation of Bones

30. Growth continues until adulthood, when most
cartilage has turned to bone.
Formation of Bones

31. Joints
•Your bones work
together to move your
body.
•They work together at
places called joints.
•A joint is where two or
more bones meet.
•Joints provide flexibility
and enable the skeleton
to move.

32. Joints
•Ligaments are tissues
that connect bones to
other bones.
•When the bones in joints
move, ligaments stretch
and keep the bones in
place.

33. Joints
•Ligaments connect
bones at joints, but they
do not protect bones.
•Cartilage protects the
ends of bones.

34. Joints
Your skeletal system has two types of joints —
Immovable Joints
&
Movable Joints

35. Joints
• Immovable joints are parts of your skeleton are
made of bones that are connected but do not
move.
• Examples: skull
Immovable Joints

36. Joints
• You can move in many ways because of your
body’s movable joints.
• The three main types of movable joints and
the ligaments that hold them together.
Movable Joints

37. Joints
Ball and Socket
• Bones can move and rotate
in nearly all directions.
• Examples: hip and
shoulder

38. Joints
Hinge
• Bones can move back and
forth in a single direction.
• Examples: fingers,
elbows, knees

39. Joints
Pivot
• Bones can rotate.
• Examples: neck, lower
arm below the elbow

40. Bone Injury and Diseases
• Because bones are made of living tissue,
they can be injured.
• Bones can break.
• They can also develop disease.

41. Bone Injury and Diseases
• A broken bone is called a fracture.
• Broken bones can repair themselves, but it
takes a long time. A broken bone must be
held together while it heals.
• Sometimes a person wears a cast to hold a
bone in place while it heals.
• Sometimes metal plates and screws hold a
bone together while it heals.
Broken Bones

44. Bone Injury and Diseases
• Arthritis is a disease in which joints become
irritated or inflamed, such as when cartilage
in joints is damaged or wears away.
• When the joints become irritated, it can be
painful to move.
• Arthritis is most common in adults. It can
also affect children.
Arthritis

45. Bone Injury and Diseases
• Osteoporosis is a disease that causes bones
to weaken and become brittle, or easily
broken.
• Osteoporosis can change a person’s skeleton
and cause fractures.
• Osteoporosis is most common in women over
the age of 50.
Osteoporosis

46. Bone Injury and Diseases
Osteoporosis

48. Healthy Bones
• One of the best ways to keep bones healthy
is to exercise.
• Certain types of exercise, such as running,
walking, and lifting weights, place weight
on your bones.
• These types of exercises help make bones
strong and build new bone tissue.

49. Healthy Bones
• A balanced diet also helps keep bones
healthy.
• Bones need calcium and vitamin D most of all.

50. Healthy Bones
• Calcium makes bones strong.
• It is also important for cell processes.
• If you do not have enough calcium in your
diet, your body will use the calcium stored in
your bones. This can make your bones weak.

51. Healthy Bones
• Vitamin D helps the body use calcium.

52. Homeostasis
• Homeostasis is an organism’s ability to keep
its internal conditions stable.
• Homeostasis requires that all body systems
work together properly.

53. Homeostasis
• Your skeletal system helps your body maintain
homeostasis by supplying calcium to your
nerves, heart, and muscles so they can
function properly.
• Bones also help you respond to unpleasant
stimuli, such as a buzzing mosquito. Working
together with muscles, bones enable you to
move away from or even swat a mosquito.