Respiratory System

body systems · breathing · oxygen · lungs

Lungs are spongy. Your lungs are filled with millions of tiny air sacs called alveoli that look like little grape clusters. These tiny sacs are where oxygen enters your blood and carbon dioxide leaves your body.

Nose filters air. When you breathe in through your nose, tiny hairs and sticky mucus trap dust and germs before air reaches your lungs. This keeps your lungs clean and healthy.

Diaphragm does the work. A big muscle under your lungs called the diaphragm pumps up and down to pull air in and push it out. You don't have to think about it because it works automatically.

Gas exchange happens fast. Oxygen zooms from your lungs into your blood in seconds, and then your blood carries it to every cell in your body. At the same time, waste carbon dioxide gets picked up and brought back to your lungs to breathe out.

Breathing speeds up. When you run or exercise, your muscles need more oxygen, so you breathe faster and deeper without even thinking about it. Your body automatically adjusts to give you exactly what you need.