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Class 5 Science Adventure

The Human Body: Working Systems

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Hi! I'm Vidi. Let's explore The Human Body: Working Systems together — wonder, read, then play the games to win a ⭐!

🌱Our Body Is a Team

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Vidi wonders: Right now, without you thinking about it, your heart beats, your lungs breathe and your stomach digests. How does it all work together?

Our body is made of tiny living building blocks called cells. Groups of cells form organs like the heart, lungs and stomach. Organs that work together to do a big job form an organ system.

  • 🍽️ The digestive system breaks down food.
  • 🫁 The respiratory system helps us breathe.
  • ❤️ The circulatory system moves blood around.
  • 🦴 The skeletal system holds us up.

All the systems work as a team to keep us alive and healthy.

BrainLungsHeartStomach

🤔 Vidi's Wonder Questions

What is a cell?

A cell is the tiniest living building block of the body. You are made of billions of them! Different cells build different parts — muscle cells, blood cells, skin cells and more.

What is an organ system?

An organ system is a group of organs that work together for one big job. For example, the mouth, stomach and intestines together form the digestive system.

🤖 Vidi's Key Points

  • The body is made of cells → organs → organ systems.
  • Each system does a big job (digesting, breathing, etc.).
  • All systems work together as a team.

🐝The Digestive System

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Vidi wonders: When you eat a roti, where does it go, and how does your body get energy from it?

The digestive system breaks food into tiny bits the body can use. Food takes a journey:

  • 👄 Mouth — teeth chew the food and saliva softens it.
  • ⬇️ Food pipe — carries food down to the stomach.
  • 🫃 Stomach — churns and breaks the food down further.
  • 🌀 Small intestine — takes the goodness (nutrients) into the blood.

The leftover waste leaves the body when we go to the toilet.

1. Mouth2. Food pipe3. Stomach4. Intestine

🤔 Vidi's Wonder Questions

Why must we chew food well?

Chewing breaks food into small pieces and mixes it with saliva. This makes it easier for the stomach to digest, so we get more goodness from our food.

Where is the food's goodness taken in?

In the small intestine. The digested nutrients pass through its walls into the blood, which carries them to every part of the body.

🤖 Vidi's Key Points

  • Digestion breaks food into tiny useful bits.
  • Path: mouth → food pipe → stomach → small intestine.
  • Nutrients pass into the blood; waste leaves the body.

☀️Breathing: The Respiratory System

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Vidi wonders: You breathe about 20,000 times a day without trying. What happens to the air inside you?

The respiratory system takes in the air we need and removes air we do not.

  • 👃 We breathe IN air through the nose.
  • 🫁 Air goes down to two lungs in the chest.
  • 💨 The lungs take in oxygen (which the body needs) and pass it to the blood.
  • ♻️ We breathe OUT a waste gas called carbon dioxide.
Air inWindpipeLungs

🤔 Vidi's Wonder Questions

Why do we breathe faster after running?

Running makes muscles work hard, so they need more oxygen. We breathe faster and deeper to take in extra oxygen and remove the extra waste gas.

What does the body do with oxygen?

The body uses oxygen to get energy from food, in every cell. Without oxygen, our cells could not make energy — which is why breathing never stops!

🤖 Vidi's Key Points

  • The respiratory system handles breathing.
  • We breathe in oxygen and breathe out carbon dioxide.
  • Air goes nose → lungs → blood.

💧The Heart and Blood

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Vidi wonders: Your heart squeezes about once every second, all day and all night, for your whole life. What is it pumping?

The circulatory system carries blood all around the body. At its centre is the heart — a strong muscle that pumps blood.

  • ❤️ The heart pumps blood through tubes called blood vessels.
  • 🩸 Blood carries oxygen and food to every part of the body.
  • ♻️ It also carries away waste.
  • 💓 You can feel your heartbeat as your pulse.
HeartBlood outBlood in

🤔 Vidi's Wonder Questions

What does blood do?

Blood is the body's delivery service! It carries oxygen and food to every cell, and takes away waste. It travels round and round, pushed by the heart.

Where can I feel my pulse?

Press two fingers gently on your wrist or the side of your neck. The little throb you feel is your pulse — your heart pumping blood with every beat!

🤖 Vidi's Key Points

  • The heart is a muscle that pumps blood.
  • Blood carries oxygen and food, and removes waste.
  • We feel the heartbeat as our pulse.

🍃Bones, Muscles and the Brain

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Vidi wonders: What holds you up, lets you move, and is the boss of your whole body?

Three more amazing systems keep us moving and thinking:

  • 🦴 Skeleton (bones) — gives the body its shape, holds it up and protects organs (the skull guards the brain).
  • 💪 Muscles — pull on bones to make us move, run and lift.
  • 🧠 Brain — the control centre. It thinks, remembers and sends messages to the whole body.
BonesMusclesBrain

🤔 Vidi's Wonder Questions

How do bones and muscles work together?

Muscles are joined to bones. When a muscle tightens, it pulls the bone and the body part moves. Bending your arm, the muscle pulls the lower arm up — try it!

Why is the skull so hard?

The skull is hard bone that protects the soft, precious brain inside, like a strong helmet. It keeps your control centre safe from bumps.

🤖 Vidi's Key Points

  • The skeleton supports and protects the body.
  • Muscles pull on bones to make us move.
  • The brain is the control centre that thinks and sends messages.

🧪 Try it at Home!

Feel your own amazing body at work — find your pulse and your breathing! 💓

🧺 You will need

  • A clock or timer with seconds
  • A notebook
  • Some space to do star jumps

👣 Steps

  1. Sit quietly. Press two fingers on your wrist or neck to find your pulse.
  2. Count how many beats you feel in 30 seconds, then write it down.
  3. Now do 20 star jumps!
  4. Quickly find your pulse again and count for 30 seconds.
  5. Compare — is your heart beating faster after exercise? Why?
👀 Watch for: After exercise your heart beats faster to send more oxygen to your busy muscles, and you breathe faster too. You just measured your body's teamwork!
🛡️ Grown-up helper: Stop if you feel dizzy or unwell. Do the jumps in a clear space, and ask a grown-up if you are unsure.

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