What do the lungs do? (7 functions)

What do the lungs do? (7 functions)

The lungs are the centerpiece of the respiratory system, working tirelessly to ensure every cell in your body receives the oxygen it needs to survive.

Whilst their primary job is breathing, the lungs also act as a filter, a pH regulator, and even a protector of the heart.

Anatomy of the Lungs

The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax).

• The Right Lung: Slightly larger and made up of three lobes.

• The Left Lung: Slightly smaller (to make room for the heart) and made up of two lobes.

• The Alveoli: The “business end” of the lungs. These are millions of tiny air sacs where the actual exchange of gases takes place.

Primary Functions: Gas Exchange

1. Oxygenation (Inhalation)

The most vital function of the lungs is to bring oxygen into the body. When you inhale, air travels down the trachea and into the alveoli. Oxygen passes through the thin walls of the alveoli and into the bloodstream, where it is picked up by red blood cells to be delivered to tissues.

2. Carbon Dioxide Removal (Exhalation)

As your body’s cells use oxygen, they produce carbon dioxide ($CO_2$) as a waste product. The blood carries this $CO_2$ back to the lungs. It moves from the blood into the alveoli and is expelled from the body when you breathe out.

Secondary Functions: Protection and Balance

3. pH Regulation (Acid-Base Balance)

The lungs help maintain the body’s ideal pH level (around 7.4). If the blood becomes too acidic, the brain signals the lungs to breathe faster to “blow off” excess $CO_2$. This rapid adjustment is critical for preventing metabolic distress.

4. Filtration and Protection

The lungs act as a shield against the outside world.

• Mucociliary Clearance: The airways are lined with mucus and tiny hairs called cilia. These trap dust, bacteria, and pollutants, moving them upward to be coughed out or swallowed.

• Macrophages: Specialised immune cells inside the lungs “eat” harmful particles that manage to bypass the cilia.

5. Blood Reservoir

The lungs can hold a significant volume of blood. In certain physical conditions (like sudden exertion or heart failure), the lungs can act as a reservoir, adjusting the volume of blood available to the left side of the heart to maintain cardiac output.

6. Vocalisation (Speech)

While we think of speech as a function of the throat, it is entirely powered by the lungs. Controlled exhalation provides the airflow needed to vibrate the vocal cords in the larynx, allowing us to speak, sing, and shout.

7. Ciliary and Metabolic Roles

The lungs are chemically active. They convert Angiotensin I to Angiotensin II using the Angiotensin-Converting Enzyme (ACE) found in lung capillaries. This process is essential for regulating your body’s blood pressure.

Common Conditions Affecting Lung Function

When the functions above are compromised, it usually manifests as respiratory disease:

• • Asthma: Inflammation that narrows the airways.

  • COPD (Chronic Obstructive Pulmonary Disease): Damage to the alveoli usually caused by long-term smoking.

  • Pneumonia: An infection that fills the alveoli with fluid, preventing gas exchange.

Summary: Lungs at a Glance

How to Keep Your Lungs Healthy

1. Stop Smoking: This is the single most effective way to protect lung tissue.

2. Exercise: Aerobic activity improves the efficiency of your lungs and heart.

3. Monitor Air Quality: Avoid pollutants and second-hand smoke whenever possible.