Notes For All Chapters – General Science Class 6
Our Skeletal System and the Skin
1. The Skeletal System
The skeletal system is made up of bones and cartilage.
It gives shape and support to the body.
It protects important organs like the brain, heart, and lungs.
Bones are hard and made of calcium and minerals.
Main Parts of the Skeletal System
Skull – Protects the brain.
Rib Cage – Protects the heart and lungs.
Spine (Backbone) – Made of 33 small bones called vertebrae, protects the spinal cord.
Bones of Arms and Legs – Help in movement.
2. Types of Bones
There are four types of bones in our body:
Flat bones – Example: Skull, ribs.
Small bones – Example: Fingers, toes.
Irregular bones – Example: Spine.
Long bones – Example: Arms, legs.
3. Joints in Our Body
Joints are places where two or more bones meet.
They help in movement.
Types of Joints:
Hinge Joint – Moves in one direction (Example: Knee, elbow).
Ball and Socket Joint – Moves in all directions (Example: Shoulder, hip).
Gliding Joint – Bones slide over each other (Example: Wrist, ankle).
Immovable Joints – No movement (Example: Skull bones).
4. How to Keep Bones Healthy
Eat calcium-rich food like milk, cheese, and green vegetables.
Do exercise and play sports.
Get sunlight for Vitamin D.
Avoid accidents and injuries.
5. The Skin
The skin is the outer covering of our body.
It helps us to feel touch, pain, heat, and cold.
It protects the body from heat, cold, and germs.
Layers of Skin
Epidermis – Outer layer, contains melanin (gives skin color).
Dermis – Inner layer, has blood vessels, nerves, and sweat glands.
6. Functions of the Skin
Protects internal body parts.
Keeps moisture inside the body.
Makes Vitamin D.
Releases sweat to control body temperature.
7. Importance of Melanin
- Melanin is a pigment in the skin that protects us from the sun.
- Darker skin has more melanin and is better protected from sun rays.
Leave a Reply