🔬 What Are the Lungs?
The lungs are two large, spongy organs in your chest that allow you to breathe. They are part of the respiratory system and are located in the thoracic cavity, protected by the rib cage.
You have two lungs:
-
Right lung – larger, has 3 lobes
-
Left lung – slightly smaller (to make space for the heart), has 2 lobes
🌬️ Main Function: Gas Exchange
The lungs’ primary job is to exchange gases between your body and the air:
| Gas | Direction | Purpose |
|---|---|---|
| Oxygen (O₂) | Into the blood | Used by cells to make energy |
| Carbon dioxide (CO₂) | Out of the blood | Waste gas from metabolism, must be exhaled |
🧭 How Breathing Works (Step-by-Step)
-
Inhalation (breathing in):
-
The diaphragm (a dome-shaped muscle) contracts and flattens.
-
This creates a vacuum, pulling air into the lungs through the nose or mouth → trachea → bronchi → bronchioles → alveoli.
-
-
Gas exchange in alveoli:
-
Tiny air sacs called alveoli (over 300 million in your lungs!) are surrounded by capillaries.
-
Oxygen moves from alveoli into the blood.
-
Carbon dioxide moves from blood into alveoli.
-
-
Exhalation (breathing out):
-
The diaphragm relaxes, pushing air (with CO₂) out of the lungs.
-
🩺 What Supports Lung Function?
| Structure | Role |
|---|---|
| Diaphragm | Controls inhalation and exhalation |
| Pleura | A thin membrane that cushions lungs and reduces friction |
| Cilia & mucus | Trap and sweep out dust, bacteria, and other particles |
| Rib cage | Protects lungs from injury |
| Blood vessels | Transport gases to and from the lungs |
🌎 Real-Life Example: Oxygen and Exercise
-
During exercise, your body needs more oxygen.
-
Lungs breathe faster and deeper to supply more O₂ and remove extra CO₂.
-
This is why you breathe heavily after running or lifting weights.
⚠️ Common Lung Diseases
| Disease | Description |
|---|---|
| Asthma | Airways narrow and swell; causes wheezing, coughing |
| Pneumonia | Infection fills alveoli with fluid or pus |
| Chronic bronchitis | Long-term inflammation of airways |
| Emphysema | Damage to alveoli (often from smoking) |
| COVID-19 | Virus that may cause severe lung inflammation and damage |
| Lung cancer | Abnormal cells grow uncontrollably in lung tissue |
🧠 Cool Facts About the Lungs
-
Surface area of alveoli = about a tennis court (70–100 m²)
-
You breathe about 20,000 times per day
-
Lungs can float in water due to air inside
-
Lungs aren’t exactly the same size – left lung is smaller
-
Your lungs start working before you're born (practice breathing in womb)
🏺 Historical Notes
-
Galen (2nd century) believed lungs cooled the heart (wrong, but influential!)
-
Harvey (17th century) proved blood circulates through lungs and heart
-
Modern medicine uses spirometers to measure lung function
-
Mechanical ventilators (invented in the 20th century) saved millions of lives