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Body Lab 3-5 / Week 05 / Wednesday
3/6
Week 05 · Lungs and Breathing

Wednesday

The breathing muscle
// Oxygen in, carbon dioxide out
⏱ about 15 min

Wednesday: The Breathing Muscle

Rocket tries to blow up his lungs like a balloon. "Grow, lungs!" he says. Nothing special happens.

Raven giggles. "What do you notice about your belly and ribs when you breathe?"

Nova floats beside Rocket. "Lungs are like sponges," she says. "Look for the muscles that move around them."

Rocket puts his hands on his ribs and takes a slow breath. "Something is moving down there!"

Lungs need help

Your lungs cannot get bigger all by themselves.

Muscles do the work. The main one is the diaphragm (DYE-uh-fram).

The diaphragm is a dome-shaped muscle below your lungs.

It sits like a floor under your chest.

Breathing in and breathing out

When you breathe in, the diaphragm tightens and moves down.

Muscles between your ribs pull your ribs up and out.

Now your chest has more space. Air rushes into your lungs.

When you breathe out, the diaphragm relaxes and moves back up.

Your chest gets smaller, and air flows out, like air leaving a balloon.

DiaphragmChest spaceAir
Breathing inTightens and moves downGets biggerFlows in
Breathing outRelaxes and moves upGets smallerFlows out
Safety first
Breathe slowly and gently. Stop if you feel dizzy.
Never hold your breath for a long time.
Sit or stand in a comfortable spot.
  1. Sit up tall in a chair.
  2. Place your hands on the sides of your ribs.
  3. Breathe in slowly through your nose. Feel your ribs move.
  4. Breathe out slowly. Feel your ribs move back.
  5. Now place one hand just below your ribs and breathe again.
BREATHING MUSCLE CHECK
  • Read the question.
  • Tap your answer.
What is the main muscle for breathing?
When you breathe in, which way does the diaphragm move?
When you breathe in, what do your ribs do?
StatementTrue or false?
Lungs can get bigger all by themselves.?
The diaphragm is below the lungs.?
When the diaphragm relaxes, you breathe out.?
More space in your chest pulls air in.?
WHY THIS EXERCISEMuscles change the space in your chest, and air flows in or out.
ONE BREATH IN
  • ?The diaphragm tightens.
  • ?The diaphragm moves down.
  • ?The chest gets bigger.
  • ?Air flows into the lungs.
WHY THIS EXERCISEThe diaphragm moves down, the chest grows and air rushes in.
What dome-shaped muscle sits below your lungs? Type one word.
WHY THIS EXERCISEThe diaphragm is the main breathing muscle.
Breathing in, the diaphragm moves ____.
Breathing out, the diaphragm moves ____.
Lungs are like ____, so muscles must move them.

Great feeling and noticing! Tomorrow we find out how air helps you talk, and why food skips the windpipe.

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