Lung anatomy

The main function of lungs is to perform exchange of gases through breathing. This means taking in oxygen while breathing in and getting rid of carbon dioxide while breathing out.


Let's explore the fascinating structure of your lungs and how it keeps you alive and healthy. Knowing how they work can help you appreciate their importance and take steps to keep them healthy.

What are lungs?

Lungs are spongy, elastic structures that expand and contract with each breath. Made of millions of tiny air sacs called alveoli, the remarkable design of your lungs enables them to process large volumes of air daily, supporting essential bodily functions and maintaining respiration of cells in the body.

The lungs are part of the lower respiratory tract, which begins at the windpipe also called trachea, and branches into two bronchi. These bronchi further divide into smaller bronchioles which further divides into small segments and ends in air sacs which are called alveoli, where gas exchange occurs.

Borders of lungs

Have you ever thought about what keeps your lungs in place? Let's take a closer look at the borders of your lungs and how they function. Your lungs have three main borders that give them their shape and help keep them securely positioned in your chest:

Front Edge: This border touches your breastbone, forming the front part of your chest space. It helps define the front outline of your lungs.

Back Edge: Located next to your spine, this border forms the back part of your chest cavity. It provides support and stability to the bronchial tree.

Bottom Edge: This border rests on your diaphragm, a crucial muscle for breathing. It allows your lungs to move up and down as the diaphragm contracts and relaxes.

These borders help keep the lungs in place and allow for expansion and contraction during respiration. The diaphragm plays a vital role in breathing by contracting and relaxing, changing the pressure in the chest cavity and facilitating air movement.

Surfaces of lungs

The lungs have three main surfaces that interact with other parts of the body. The outer surface, covered by the pleura, faces the rib cage and allows for smooth movement during breathing.

The inner surface faces the middle of the chest, keeping the lungs from moving too far towards the heart and other organs. The bottom surface, also covered by the pleura, rests on the diaphragm and helps the lungs stay in place as it contracts and relaxes during breathing.

Diaphragm

Imagine the diaphragm as a flexible partition separating your chest cavity, where your lungs reside, from your abdominal cavity, housing your stomach and other organs. This muscle plays a pivotal role in the mechanics of breathing.

When you inhale, your diaphragm contracts. Think of it flattening out like a deflated balloon being stretched. This downward movement increases the volume of your chest cavity, creating a vacuum-like effect that draws air into your lungs. Your diaphragm relaxes, returning to its dome shape. This reduces the volume of your chest cavity, gently squeezing your lungs and pushing the air out.

Right lung

Your right lung is a bit bigger than your left lung, and has a more complex shape because it has an extra part called the middle lobe:

Upper lobe: This is the biggest part of your right lung and it's located at the top.

Middle lobe: This part is only found in the right lung and it's located below the upper lobe.

Lower lobe: This is the smallest part of your right lung and it's at the bottom.

Each of these parts is divided into even smaller sections called segments. Your right lung has a total of 10 segments.

The right lung is different from the left lung because it has to make room for your heart. Your heart is located slightly to the left of the centre of your chest, so your right lung has to curve around it. Your right lung holds a little bit more air than your left lung.

Left lung

It has two lobes:

Upper lobe:This is the biggest part of your left lung and it's located at the top.

Lower lobe:This is the smallest part of your left lung and it's at the bottom.

Similar to the right lung, each of these lobes is divided into even smaller sections called segments. Your left lung has a total of 8 segments.

Functions of lungs

Your lungs are multifunctional organs that play important roles in our body. Here's a detailed look at their various functions:

Gas exchange

Fresh oxygen intake

Your lungs bring fresh oxygen into your body and deliver it to your bloodstream.

Removing carbon dioxide

They also remove carbon dioxide, a waste product, and release it when you exhale.

Alveoli function

Tiny air sacs called alveoli do this important job.

pH Regulation

Lungs maintaining blood balance

Your lungs help keep your blood balanced and not too acidic.

Controlling carbon dioxide levels

They do this by controlling carbon dioxide levels, which can make your blood acidic if the level is too high.

Hormone and drug metabolism

Lungs processing hormones

Your lungs help process hormones and medications in your body.

Hormones and medications

They can turn them on or off as they pass through your lungs.

Preventing substance buildup

This helps prevent these substances from building up too much or too little in your body.

Blood pressure regulation

Lungs regulating blood pressure

Your lungs also help regulate your blood pressure.

ACE enzyme function

They do this by providing ACE (Angiotensin Converting Enzyme) for converting a hormone called “angiotensin I” into “angiotensin II”.

Effect of angiotensin II

Angiotensin II makes your blood vessels narrower, which increases your blood pressure.

Surfactant production

Surfactant in lungs

Your lungs make a special substance called surfactant. Surfactant helps your lungs inflate easily.

Importance of surfactant

Without it, breathing would be harder and you wouldn't be able to get enough oxygen.

Blood reservoir

Lungs storing blood

Your lungs store about 10% of your blood.

Blood released from lungs

This blood can be released quickly when your body needs it, like when you're exercising, or in an emergency.

Other functions

Temperature regulation

Temperature regulation: Your lungs help cool your body down by releasing heat by slowing or fasting pace of breathing.

Immune Defense

Immune Defense: Your lungs help protect your body from germs and particles in the air. They trap these things in mucus, which you can then cough up or blow out.

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