Grade 3 Science (NSO): Human Body

Our wonderful body

Lets brush up on the basics first. The class 1 lessons will give a nice overview of our body.

Parts of our body that we can see.

Head, skin, arms, legs, eyes , ears , nose , tongue etc

Skin in the biggest organ of our body

Sense organs are also external organs and they comprise of Nose (smell), Eyes(sight), Ears (hearing),

Tongue (taste), Skin (touch)

Parts that are inside our body

Brain, heart, lungs, stomach etc

Brain : Helps us to think and controls our body

Heart : Pumps blood to all parts of the body

Lungs : Helps us to breathe in oxygen

Stomach : Digests the food that we eat

Humans have five vital organs that are essential for survival. These are the brain, heart, kidneys, liver and lungs

Bones give support and shape to our body

Bones join together and form a framework called skeleton

It is a framework which bends around the joints.

The skeleton protects our vital organs.

Skull protects our brain

Ribcage protects our lungs and heart

Lower part of the ribcage protects our stomach, liver etc

At birth we have 305 bones

An adult has 206 bones

Muscles help our bones to move. These are soft and lie under our skin

They join the bones and help them to move

We have around 640 skeletal muscles

Muscles are made of proteins. Protein rich food like eggs, sprouts etc help us in building healthy muscles.

We have 3 types of muscles in our body: skeletal, visceral, and cardiac

Skeletal muscles consist of striped or striated fibers.
They move the various parts of the body.
Skeletal muscles are considered “voluntary” muscles because the person controls their use.

Visceral muscles are also called smooth muscles.
These muscles are found in the stomach and intestinal walls, vein and artery walls, and in various internal organs.
They are called “involuntary” because they cannot be made to work by conscious choice, but are controlled by the autonomic nervous system.

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