Bones and Muscles Notes & Questions | Class 5 Biology | Drishti OS

Bones and Muscles

What you'll learn

The skeleton — the framework of bones that gives the body shape and support.
Joints — places where two bones meet and allow movement (knee, elbow, shoulder, neck).
Muscles — tissues that contract and relax to move bones.
NCERT Looking Around 5, Chapter on Body Movements.

Key concepts

Level 1 — The skeleton

Verbal: Bones are hard and strong; together they form the skeleton that protects soft organs like the heart, lungs, and brain.

Symbolic: Skull → protects brain; Ribcage → protects heart and lungs; Backbone (spine) → protects spinal cord.

Bone/part	Protects / supports
Skull	Brain
Ribcage	Heart, lungs
Backbone	Spinal cord, gives upright posture
Limb bones	Support arms and legs, help movement

NCERT link: Body Movements — skeleton as the body's support frame.

Level 2 — Joints and muscles

Verbal: A joint is where two bones meet. Different joints allow different kinds of movement.

Real-life: Try touching your toes (hinge joint at hip/knee) or turning your neck (pivot joint).

Joint type	Example	Movement allowed
Hinge	Elbow, knee	Back and forth (like a door)
Ball and socket	Shoulder, hip	Movement in many directions
Pivot	Neck (top of spine)	Turning side to side
Fixed	Skull bones	No movement (joined firmly)

Muscles: Muscles are attached to bones. A muscle contracts (shortens) to pull a bone and move it, then relaxes back.

Worked example

Why can you bend your elbow but not your skull bones?

Step 1 — Elbow has a hinge joint that allows movement.
Step 2 — Skull bones are joined by fixed joints — no gap for movement.
Answer: Joint type decides whether movement happens.

How do muscles help you lift a bag?

Step 1 — Muscle in the arm contracts (shortens and pulls).
Step 2 — This pulls the bone connected to it, bending the elbow joint.
Answer: Muscle contraction moves bones at the joint.

Common mistakes

Mistake	Why it happens	Fix
All joints move the same way	Not observing carefully	Different joints (hinge, ball-socket, pivot, fixed) move differently
Bones move by themselves	Not knowing muscle role	Muscles pull bones to create movement
Skull has no bones joined	Confusing "fixed" with "absent"	Skull has many bones joined firmly (fixed joints)
Skeleton is only for movement	Ignoring protection role	Skeleton also protects soft organs

Quick check

Name two joints and the movement each allows.
What protects the brain?
How do muscles help move bones?
Stretch: Why do you think the skull has fixed joints instead of movable ones?

Revision tip: Move your own elbow, knee, and neck and name the joint type for each.

Open the Practice tab for graded questions on Bones and Muscles.

Bones and Muscles