🫀 🦴 🧠 🫁
Lesson

Body Systems 🫀︎

Explore how the body's major systems work together — from cells to organs — to keep every living organism alive and in balance.

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Driving Question
When you sprint for a bus, what's actually happening inside your body — and how many systems kick in at once?
🔬 Learning Science Focus 🗂️ Concept Formation 🖼️ Dual Coding 💬 Elaboration 🧠 Retrieval Practice ⚖️ Load Management
📋 MA STE Standards · Grade 6 6.MS-LS1-3

From Cells to Body Systems 🔬

Life is organized in levels. Each level is built from the one below — and if any level fails, everything above it is affected.

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Organelles
Tiny structures inside a cell that each have a specific job — like the organelles of a cell are to the cell what organs are to your body.
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Cells
The basic structural and functional unit of all living things. Every living organism is made of one or more cells.
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Tissues
A group of similar cells working together to perform a specific function. Tissues are one level above cells.
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Organs
A structure made of two or more types of tissue working together to carry out a specific job in the body.
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Body Systems
A group of organs that work together to perform a major function for the whole organism. Multiple systems interact constantly to keep the body alive.
🔑 Key Idea: If cells do not function properly, the tissues, organs, and body systems that depend on them cannot function properly either. Everything starts at the cellular level.

How Systems Work Together 🔗

No body system works alone — they are constantly depending on and supporting each other. Here's a quick reference for the key interactions.

🫀Circulatory
Respiratory Blood picks up O₂ from the lungs and delivers it to every cell in the body
Digestive Blood transports absorbed nutrients from the small intestine to cells throughout the body
Excretory Blood carries metabolic waste products to excretory organs for removal
Immune Blood vessels deliver white blood cells to sites of infection anywhere in the body
💪Muscular
Digestive Smooth muscle in the digestive tract pushes food along through peristalsis
Circulatory The heart is a muscle — cardiac muscle contraction pumps blood through the entire body; skeletal muscles also help push blood back through veins
Skeletal Muscles attach to bones via tendons and pull on them to create all movement — neither system works without the other
🦴Skeletal
Muscular Muscles pull on bones via tendons to create movement at joints
Circulatory Bone marrow produces red and white blood cells for the circulatory and immune systems
🫁Respiratory
Excretory The lungs remove carbon dioxide — a gaseous waste product — from the body when we exhale
Circulatory Blood travels to the lungs to pick up oxygen and drop off CO₂ — the two systems are inseparable gas exchange partners
🫄Digestive
Immune The gut lining is one of the body's largest immune barriers — gut bacteria and immune cells work together to block pathogens from entering the bloodstream
Excretory Solid waste passes to the large intestine for elimination; the liver filters toxins from digested material before they reach general circulation
🚽Excretory
Circulatory The kidneys filter waste from the blood — receiving blood via the renal artery and returning clean blood via the renal vein
Respiratory The lungs excrete CO₂ gas — a metabolic waste product — with every exhale, working alongside the kidneys to keep blood chemistry balanced
🛡️Immune
Skeletal Red and white blood cells — including the immune system's key fighters — are produced in bone marrow inside the skeletal system
Circulatory The bloodstream carries white blood cells and antibodies to any site of infection anywhere in the body

Dive Deeper 🔍

Now that you've seen how the systems connect, go deeper — explore interactive maps or see what happens when things go wrong.

Vocabulary to Know

Every term below appeared in this lesson. Click any pill to jump to its explanation.

👆 Click any term to jump to its explanation in the lesson

Circulatory System Digestive System Respiratory System Excretory System Skeletal System Muscular System Nervous System Immune System Organelles Cells Tissues Organs Body Systems

Watch & Learn 🎬

Watch this video to reinforce the major body systems and how they interact to keep the body alive and in homeostasis.

Body Systems Quiz 📝

15 questions on the major body systems, their functions, and how they work together. Fill in your info below — your score will be sent to your teacher when you submit.

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More Learning

The lesson is just the beginning — go deeper, test your skills, or see how it all connects.