Respiratory System

What is the respiratory system?

The respiratory system, also known as the respiratory tract, is the group of organs and tissues spanning from the mouth and nose, to the lungs.

It is the system which allows gas exchange to take place in the body. This is when the oxygen you breathe in is absorbed and transported around the body to keep our cells alive; and carbon dioxide produced as waste matter by cells is removed from the body.

Breathing is an automatic reflex and the respiratory system maintains the correct amount of oxygen and carbon dioxide in our bloodstream without us even being aware of the important work it is doing. The average adult takes about 12 to 20 breaths a minute or over 700 million breaths in a lifetime.

Nose and Mouth

Air enters and exits your body through two possible openings, the nose or the mouth. These organs warm, moisten and filter the air we breathe as cold, dry air or foreign particles can irritate the lungs. Cold air can also make us more prone to respiratory infections – this is the reason that colds and flu are more frequently encountered in the winter.

The nose is the preferred route for air to enter the respiratory system. It is lined by hair and mucus which traps any dust, dirt or germs preventing them from travelling further into your respiratory tract.

The mouth is an alternative route of entry for air to get into the respiratory system. It is not as effective at warming and filtering the air as the nose is, because it does not have hair and mucous lining. This is why it is better to breathe through your nose.

However, the mouth is useful when you are suffering from a blocked nose, or need to take in larger amounts of air, such as when you are running.

Throat

The openings for the mouth and nose meet at the throat - a junction for the digestive system and the respiratory system. One tube, the oesophagus or gullet, leads off to the stomach. The other, the trachea, connects to the lungs. The throat consists of the pharynx, the larynx and the epiglottis.

• The epiglottis is a flap of cartilage which acts as a valve for food and air. At rest it sits upright allowing air into the larynx and trachea. When you swallow, the epiglottis folds back to cover the entrance of the larynx causing food to travel into the oesophagus.
• The pharynx is a channel for air and food which is about 12 cm long. When food reaches the pharynx a reflex action is initiated to cause you to swallow, propelling food into the oesophagus. The pharynx can become inflamed – a condition called pharyngitis giving rise to the main symptom of sore throat.
• The larynx is also known as the voice box, and is the structure which allows us to speak. It connects the pharynx with the trachea. The larynx can also become inflamed resulting in hoarseness or a loss of voice.

Trachea

The trachea is also called the windpipe. It is a flexible tube which in most adults it is about 10cm long, and is made of about 20 rings of cartilage. It allows air to pass to and from the lungs. The trachea is lined with mucus and small hair-like structures known as cilia. These sweep dust or foreign particles out of the respiratory system.

The trachea connects the larynx to two smaller tubes called the bronchi, one bronchus leading to each lung.

Sometimes, food goes down ‘the wrong way’ when we shallow. This is when the epiglottis has not functioned well leading to food entering the larynx and trachea. This results in bouts of coughing as the body attempts to rid itself of the foreign body.

The organs of respiration from the nose down to the trachea are known as the upper respiratory system or upper airways.

Bronchi

The bronchi are the two main tubes which lead from the trachea into the lungs. They branch into increasingly smaller tubes known as bronchioles, the smallest being less than 0.5 mm in diameter. These bring air deep into the lungs and end in sacs or balloon-like structures known as alveoli.

Inflammation of the bronchi is known as bronchitis. This is the area of the body that becomes inflamed in conditions such as bronchitis or chronic obstructive airways disease.

The bronchioles can also become inflamed as a result of infection, a condition known as bronchiolitis. They may also become inflamed and narrowed as a result of asthma.

Lungs

Each bronchiole ends in alveoli and there are about 3 million of these in each lung. They make up the main bulk of the organ we call the lung. It is through the alveoli that oxygen passes into blood and carbon dioxide is removed from blood.

The lungs are two large organs, located either side of your heart and are the main organs of the respiratory system. The left lung is slightly smaller than the right, to make room for the heart within the ribcage. They have a large surface area – estimated to be equivalent to a tennis court - so that there is plenty of space for the exchange of gases to take place.

Infection of the lungs (alveoli) is known as pneumonia.

How do I know if my respiratory system is working well?

Your respiratory system is a vital part of your body, as without it, you would not be able to breathe and stay alive. If it is working well you will:

• Feel generally fit and healthy
• Not notice you are breathing unless you are exercising hard, when your breathing may become heavier
• Not get out of breath easily
• Not be coughing regularly.

If you notice that you are panting as you walk or climb stairs, or you have a persistent cough , then it may be worth seeking medical attention.

What can I do to keep my respiratory system healthy?

There are several things you can do to keep your respiratory system happy and healthy:

• Regular exercise – this is good for improving your breathing and heart rates
• Don’t smoke – smoking is probably the worst thing you could do to your respiratory tract as it slowly and progressively destroys its delicate tissues. When you smoke, the fine cilia which trap dust particles and keep the mucous lining clean, become ineffective. This leads to contaminated mucus building up in the respiratory system.
• Keep plants – if you have plenty of living plants in your house and your office this can, surprisingly, have a strong positive impact on your respiratory system. Plants absorb the carbon dioxide which you don’t want in your body, and produce a lot of oxygen for you to breathe in
• Avoid dust or pet hair – this tends to float around the air and are inhaled into your lungs. The mucus lining your respiratory tract will trap these particles but thy can lead to irritation and inflammation
• Drink plenty of water – water is great for flushing out your system and keeping you healthy. It also prevents the mucus lining your respiratory tract becoming too thick or contaminated
• Eat a balanced diet – this is essential to keep you healthy, but it is also shown that a diet full of good nutrients and vitamins strengthens your respiratory system and keeps it working in tip top condition.