1. The musculoskeletal system Dr. T.

2. Why are we looking at these two systems together?
It is because these two systems work together so closely.
The skeletal system gives us our shape, supports our bodies, protects vital organs, and is a reservoir of important minerals.
Muscles provide us with the power that allows us to move around.
Without a skeletal system to provide support, our muscles could not function!

3. Components of the Musculoskeletal system
Bones
Cartilage
Ligaments
Tendons
Skeletal (Striated) muscles.
Note: There are two other types of muscle tissue we will learn about, but they are not considered part of the musculoskeletal system.

4. What are muscles? Muscles consist of cells and contractile fibers.
Muscle work by shortening in length.
You have two sets(or more) of muscles attached to many of your bones which allow them to move.
There are 630 active muscles in your body.
Muscles can only pull, they can’t push.

5. The Three Types of Muscles
More on muscles.
The Three Types of Muscles
Type of Muscle Smooth Muscle Cardiac Muscle Skeletal Muscle
Appearance Smooth Striated Striated
Voluntary or
Involuntary Involuntary Involuntary Voluntary
Function Controls Controls Moves bones.
movement of contractions Work in pairs.
internal organs of the heart When one contracts
the other relaxes.
Attached to bones by tendons.

6. Check for learning.
On the paper provided, answer the following questions without referring to your worksheet.
1. What are the 5 components of the musculo-skeletal system?
2. What are the 3 types of muscle tissue?

7. Bones Like everything else in your body, your bones consist of cells.
Two types.
Osteoblasts: Cells which build bones.
Osteoclasts: Cells which break down bones
To release minerals, like calcium
How to remember the difference?
OsteoBlasts Build Bone. 3 B’s.

8. Thanks for your support.
Without a bones you’d be floppy like a beanbag.
Could you stand up? Forget about it.
Could you walk? No way, man!
Without bones you’d be a puddle of skin and guts on the floor.

9. The job of the bones. Your skeleton has several jobs.
Some bones, like your backbone, provide structure.
Other bones, like your skull and rib cage protect vital organs.
The tiniest bones in your body, in the inner ear, help to transmit sound waves to your brain.

10. So how many bones do we have?
Actually, you have less than you once did.
As a new born, you had over 300 bones.
As you grew up, many of these bones fused together.
You now have 206 elegant bones in your body.

11. So how do muscles and bones do their jobs?
With a lot of help.
Along with muscles and bones, you need joints.
Joint provided flexible connections between bones. Joints are primarily made up of tissue called ligaments.
Tendons attach bone to muscle, ligaments attach bone to bone.

12. Types of joints
Hinge joints: Like in your knee, enable bones to move back and forth.
Pivot joints: Like in your neck, enable you to turn your head around.
Ball and socket joints: Like in your shoulder, enable you to move your arms 360 degrees.
Semi-moveable joints: Like the ones between the vertebrae in your backbone.

13. Are bones alive?
Absolutely. If not, then broken arms and legs would never heal.
Like all other cells in your body, bone cells need nutrients and oxygen and they produce wastes.
When you break a bone, blood clots form to close the space between the two segements. Osteoblasts the begin the process of depositing bone to heal the fracture.

14. What is bone marrow? Many of your larger bones are hallow.
Being hallow helps to reduce the weight of your bones.
In the center of these bones, bone marrow makes new red and white blood cells.
So it turns out that your bones actually make blood! How cool is that?

15. Fun bone facts The human hand has 27 bones, your face has 14
The longest bone in your body is your femur, ¼ your height.
Humans and Giraffes have the same number of bones in their necks.

16. Check for learning II
On your answer sheet, answer the following questions. Do not refer to your worksheet.
How many different types of bone cells are there?
List three functions of your bones.
How many bones does a newborn baby have? How many bones do you have?