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By: Ikedi Ani-okoye

Understanding the respiratory system

The technical term for breathing is respiraton. With each breath, air enters the lungs and oxygen passes into the blood through the delicate tissues of the lung. Every cell in our bodies needs oxygen to work properly. Without oxygen, muscles cannot contract, nerves cannot send impulses, the heart stops and the brain cannot function. The end product of respiration is carbon dioxide, which leaves the blood as oxygen enters it. If the lungs did not expel carbon dioxide as we breathe out, confusion, coma and death would follow.

The breathing apparatus

The lungs form the main part of the respiratory system - two spongy organs lying within the chest cavity. They are surrounded and protected by a bony cage comprising the ribs, spine and sternum. The diaphragm is a dome-shaped muscle attached to the lower ribs lying under the lungs and is the main muscle of breathing control. Other muscles that help with breathing, especially during exercise, or in times of stress or illness, are the intercostal muscles lying between each rib.

Together these structures form an airtight, protective cage around the lungs.
Air reaches the lungs through a series Of branching airways, which become progressively more numerous and smaller, like the branches of a tree. Air enters the body through the nose and mouth, and down the throat. lt then passes the larynx, or voice box, Which contains the vocal chords. The epiglottis is a flap of cartilage that covers the larynx when we swallow food, in order to prevent food from entering the trachea, or windpipe.

The air then reaches the trachea, which soon divides into two branches called bronchi - one going to the left lung and the other to the right. These branch into smaller vessels called bronchioles. The bronchioles taper into smaller and smaller branches, until they end in tiny sacs of lung tissue called alveoli. This is where gas exchange takes place. Tiny branches of veins and arteries are wrapped around the alveoli, and through their walls, oxygen and carbon dioxide are transferred in and out of-the blood.

How do we breathe?

We breathe automatically. Apart from being able to control how fast or deeply we breathe over a short period, our breathing is beyond our voluntary control. The respiratory centre in the brain stem controls the basic rhythm of breathing. lt is from here that messages are sent to and from the nerves supplying the diaphragm and intercostal muscles. 'This leads to a continuous cycle of relaxation and contraction of the breathing muscles.

In an adult, the normal rate for breathing at rest is 13-17 breaths per minute. This rate increases during exercise, which is a normal response to the body's increased demand for oxygen. An increased rate at rest or during only mild exertion can be a sign of physical illness. Psychological problems, such as extreme anxiety end panic attacks, can also increase breathing rate.

In babies and young children, breathing rate is much higher, ranging from around 50 breaths a minute in a baby under 1 year to 30 breaths a minute in children over 5 years.

Problems with breathing

Breathing problems may be caused by:

Heart disease. Chest infection. Lung tumour or lung disease. Collapsed or punctured lung. Asthma. Smoking. Fear, panic and anxiety. . Inhalation of Fumes. Choking. * Chest injury. Head injury.

A person who develops breathing problems suddenly must be seen by a doctor without delay. While you are waiting for help to arrive, give any necessary first aid.