US Trends

what does each part of the illustrated lung model represent in relation to the human breathing system

Each part of a typical “bottle-and-balloons” illustrated lung model is designed to copy a real part of the human breathing system and show how breathing works.

What each part represents

Most school models use:

  • A clear plastic bottle
  • Two small balloons inside
  • A straw or tube
  • A rubber/plastic sheet pulled over the bottom (often a balloon cut in half or cling film)

Here’s what each part usually stands for in relation to the human breathing system:

  1. Plastic bottle → Rib cage & chest cavity
    • The bottle is the hard “wall” around the model lungs.
 * This represents your **rib cage and chest cavity** , which surround and protect your lungs and give them a fixed space to expand into.
  1. Two small balloons inside → Lungs
    • The small balloons act as the lungs themselves.
 * When they inflate, that shows **inhalation** (breathing in); when they deflate, that shows **exhalation** (breathing out).

 * In your body, your lungs fill with air and empty as air moves in and out through the airways.
  1. Straw or tube → Trachea (windpipe) and main bronchi
    • The straw/tube going down into the balloons works like your trachea , also called the windpipe.
 * Where the straw splits into two (if it does), that represents the **left and right bronchi** , which are the main airways that carry air into each lung.
  1. Rubber/plastic sheet at the bottom → Diaphragm
    • The flexible sheet attached to the open bottom of the bottle acts as the diaphragm , a large sheet of muscle under your lungs.
 * When you **pull the sheet down** , the space inside the bottle increases, pressure drops, and the balloons fill with air, just like when the diaphragm contracts and pulls down to help you inhale.

 * When you **push the sheet up** , the space decreases, pressure rises, and the balloons empty, like your diaphragm relaxing and moving upward when you exhale.

How this shows real breathing

In your real body:

  • Air travels through your nose or mouth → throat → larynx → trachea → bronchi → bronchioles → alveoli (air sacs).
  • The diaphragm and the muscles between your ribs change the size of the chest cavity, which pulls air in or pushes it out.

In the model:

  • The balloons show how lungs inflate and deflate.
  • The straw shows the path air takes to get into the lungs.
  • The sheet shows how movement of the diaphragm changes chest volume and air pressure, causing air to move.

What the model leaves out

Real lungs and airways are more complex than the simple model:

  • It does not show bronchioles and alveoli , where oxygen actually moves into the blood.
  • It does not show blood vessels , heart , or the nose and mouth.
  • It simplifies the rib cage and breathing muscles to just a solid bottle and one moving sheet.

Short recap (TL;DR)

  • Bottle = rib cage / chest cavity.
  • Inside balloons = lungs.
  • Straw/tube = trachea and main bronchi.
  • Bottom sheet/balloon = diaphragm.

Together, they model how changing the space in your chest (with the diaphragm) makes air move in and out of your lungs in real life.

Information gathered from public forums or data available on the internet and portrayed here.