💨 What Happens in Alveoli?
Each alveolus is surrounded by tiny blood capillaries. Here’s how oxygen and carbon dioxide are exchanged:
- Inhalation (Breathing In):
- Air enters lungs and fills alveoli.
- Oxygen in alveoli moves into the blood capillaries by diffusion.
- Blood becomes oxygen-rich.
- Exhalation (Breathing Out):
- Blood brings carbon dioxide (a waste gas) to alveoli.
- Carbon dioxide moves into the alveoli by diffusion.
- It is then breathed out.
📌 Diffusion = movement of particles from high concentration to low concentration.
🧠 Example:
Spray air freshener in one corner — soon, you smell it everywhere. That’s diffusion in action.
🔁 Summary of Airflow Pathway:
Nostrils → Nasal Cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
🧠 Recap: Why is this system important?
- Provides oxygen to every cell in the body.
- Removes carbon dioxide, a waste product.
- Helps in speech (larynx).
- Cleans and warms the air.
- Maintains balance of gases in the blood.
🫁 Mechanism of Breathing or Ventilation
🔹 What is Breathing or Ventilation?
Breathing (also called ventilation) is the process of moving air in and out of the lungs.
✅ Simple Definition:
- Inhalation (or inspiration) = taking air into the lungs.
- Exhalation (or expiration) = pushing air out of the lungs.
🧠 Real-life Example:
Think of your lungs like a balloon. When you blow air in, the balloon inflates (like inhalation). When you let it go, the air rushes out (like exhalation).
But here’s the twist: lungs don’t move on their own! They don’t have muscles to pull or push air. Instead, they depend on surrounding muscles to create pressure changes that move air in and out.