Welcome to GattPrep!
Hello, science explorer! 👋🏽
Take a moment to move your fingers or stand up and stretch. Every time you move, sit, or even blink—your skeletal system is in action! It’s not just a pile of bones. It’s a brilliant system that supports your body, protects your organs, and allows you to move around.
In this lesson, we’ll dive into what the skeletal system is, why it matters, and how it keeps you upright and active. You’ll also learn the major parts of the human skeleton, the types of bones and joints, and see how it all works together like a well-oiled machine.
The skeletal system is the framework of bones and cartilage that supports your body, protects internal organs, and enables movement. In adult humans, there are 206 bones.
It does more than hold you up! The skeletal system:
Protects delicate organs (like the brain and heart)
Produces blood cells in the bone marrow
Stores minerals like calcium and phosphorus
The human skeleton has two main parts:
| Part | Description | Example Bones |
|---|---|---|
| Axial Skeleton | The central part of the body | Skull, spine (vertebrae), ribs |
| Appendicular Skeleton | The limbs and girdles attached to the axial skeleton | Arms, legs, shoulders, hips |
| Function | Explanation |
|---|---|
| Support | Provides structure to the body |
| Protection | Shields vital organs (e.g., skull protects brain) |
| Movement | Bones work with muscles to enable motion |
| Blood Cell Production | Bone marrow makes red and white blood cells |
| Mineral Storage | Stores essential minerals for the body |
Joints are places where two or more bones meet. They allow movement and flexibility.
| Type of Joint | Movement | Example |
|---|---|---|
| Fixed (Immovable) | No movement | Skull bones |
| Hinge | Back-and-forth | Elbow, knee |
| Ball-and-Socket | Rotational | Shoulder, hip |
| Pivot | Rotation around an axis | Neck (between skull and spine) |
| Gliding | Sliding movements | Wrist, ankle |
Try bending your elbow. The biceps muscle contracts and pulls on the radius bone, while the triceps relaxes. This is called a muscle-bone interaction. Bones don’t move by themselves—they need muscles!
🧠 Problem: Kwame falls and breaks the bone in his forearm. His doctor says the radius bone is fractured.
Which part of the skeleton does the radius belong to?
What kind of joint connects the radius to the upper arm bone (humerus)?
Why does Kwame feel pain when he tries to rotate his wrist?
✅ Step-by-Step Solution:
Radius is part of the appendicular skeleton (the arm).
The hinge joint at the elbow allows the radius and humerus to move back and forth.
Pain during wrist rotation could be due to damage around a pivot joint at the forearm or stress on surrounding tissues and nerves.
✔️ Answer:
Appendicular skeleton
Hinge joint
Because the pivot joint and surrounding nerves are affected
(a) The ___________ skeleton includes the skull and backbone.
(b) The type of joint at the shoulder is called a __________ joint.
Answers:
(a) axial
(b) ball-and-socket
| Action | Joint Type |
|---|---|
| (i) Bending your knee | A. Ball-and-socket |
| (ii) Turning your head | B. Hinge |
| (iii) Raising your arm in a circle | C. Pivot |
Answers:
(i) → B
(ii) → C
(iii) → A
Q: Why are bones important for blood cell production?
A: Because red bone marrow in certain bones produces red and white blood cells.
Let’s review what we learned:
The skeletal system supports the body, allows movement, and protects organs.
It is made up of the axial and appendicular skeletons.
There are different types of joints like hinge, ball-and-socket, and pivot joints.
The bone marrow in certain bones produces blood cells.
Bones work with muscles to move the body.
Think about how many joints you’ve used so far today. Can you name 3 different joints you used and explain the type of joint each one is?
Write your answer in your science journal or discuss with a friend!
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