1. Human Biology and Health Chapter 1, Section 2
The Skeletal System
Human Biology and Health
Chapter 1, Section 2

3. What is the SKELETON?
The framework of the body made up of all the bones in the body
Determines the shape of the body
Comes from a Greek word meaning “a dried body”

4. 5 Major Functions of the Skeletal System
Provide shape and support
Enable movement
Protect the organs
Produce blood cells
Store minerals and other materials until needed by the body

5.  Provide shape and support
BACKBONE (vertebral column) is the center of the skeleton
Made of 26 small bones call VERTEBRAE (singular vertebra)

6.  Provide shape and support continued…
Notice all bones in the skeleton are in some way connected to this column.

7. CHECK POINT
Q. Why is the vertebral column considered the center of the skeleton?
A. All the bones in the skeleton are in some way connected to the backbone.

9.  Enable movement The skeleton allows you to move
Most of the bones are associated with muscles
The muscles pull on the bones to make the body move

10.  Enable movement continued…
What is a JOINT?
A place where two bones come
together
Allows bones to move in different
ways

11.  Enable movement continued…
Two Types of Joints
IMMOVABLE JOINTS
- allow little or no movement

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Two Types of Joints
MOVABLE JOINTS
Make up most of the joints in the body
Allow the body to make a wide range of movements
Held together by strong connective tissue call LIGAMENTS

13.  Enable movement continued…
Two Types of Joints
CARTILAGE is a more flexible type of connective tissue that covers the ends of bones to keep them from rubbing against each other

14.  Enable movement continued…
Two Types of Joints

15. CHECK POINT Q. How are movable joints held together?
A. With strong connective tissue called ligaments

16. Why didn't the skeleton cross the road?
It didn't have the guts!
What do you call a skeleton who won't work?
Lazy bones!

17.  Enable movement continued…
Types of Movable Joints
 Enable movement continued…
Hinge Joint – allows forward and backward motion
Example: knee and elbow

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Types of Movable Joints
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Ball-and Socket Joint – allows the greatest range of motion
Example: shoulder and hips

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Types of Movable Joints
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Pivot Joint – allows one bone to rotate around another
Example: neck

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Types of Movable Joints
 Enable movement continued…
Gliding Joint – allows one bone to slide over another
Example: wrist and ankle

21. Protect the organs Bones protect most organs in the body
Example: breastbone and ribs form a cage around the heart and lungs

22. Produce blood cells
Blood cells are produced in marrow located in long bones like the legs and arms
The process is known as hematopoiesis
Produces approximately 500 billion blood cells per day

23. Store minerals and other materials until needed by the body
Stores calcium, phosphorus, and other minerals
Releases small amounts into the blood when needed

24. CHECK POINT Q. What part of the bone produces blood cells?
A. The marrow.

25. What smells the best at dinner?
Your nose!
Why is your nose in the middle of your face?
Because it is the scenter!

26. Bone Structure
Bones are complex living structures that undergo growth and development

27. Bone Structure
A thin, tough membrane covers all of the bone except the ends
Blood vessels and nerves enter and leave the bone through the outer membrane

28. Bone Structure Compact bone layer just below the membrane
Hard and dense but not solid
Contains small canals for blood vessels and nerves

29. Bone Structure Spongy bone Layer just below the compact bone
Has small spaces within it
Can also be found at the end of bones
Lightweight but strong

30. Bone Structure Marrow Soft connective tissue Two types: red and yellow
Red marrow – produces blood cells
Yellow marrow – stores fat for energy reserve

31. CHECK POINT
Q. Name three levels in bone

32. CHECK POINT
Q. What does red marrow do?
A. Produces blood cells.

33. CHECK POINT
Q. What does yellow marrow do?
A. Stores fat for energy.

34. THINK DEEPER
Q. Short bones, like those in the fingers are mostly spongy bone. Why do long bones have more compact bone?
A. Long bones have compact bone because they are used to support the body and need to be stronger.

35. Taking Care of Your Bones
Diet
Eat well-balanced diet
Exercise
Weight-bearing activities help bones grow stronger and denser

36. Osteoporosis
A condition in which the body’s bones become weak and break easily