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Our cells need oxygen to survive
One of the waste products produced by cells is another gas called carbon dioxide. The respiratory system takes up oxygen from the air we breathe and expels the unwanted carbon dioxide.
The main organ of the respiratory system is the lungs
Other respiratory organs include the nose, the trachea and the breathing muscles (the diaphragm and the intercostal muscles). Breathing in through the nose warms and humidifies the air that is breathed in.
Nose hairs help to trap any particles of dust
The warmed air enters the lungs through the windpipe, or trachea. The trachea is a hollow tube bolstered by rings of cartilage to prevent it from collapsing. The lungs are inside the chest, protected by the ribcage and wrapped in a membrane called the pleura.
The lungs look like giant sponges
They are filled with thousands of tubes, branching smaller and smaller. The smallest components of all are the air sacs, called ‘alveoli’.
Each one has a fine mesh of capillaries
This is where the exchange of oxygen and carbon dioxide takes place.
To stay inflated, the lungs rely on a vacuum inside the chest. The diaphragm is a sheet of muscle slung underneath the lungs.
When we breathe, the diaphragm contracts and relaxes
This change in air pressure means that air is ‘sucked’ into the lungs on inhalation and ‘pushed’ out of the lungs on exhalation. The intercostal muscles between the ribs help to change the internal pressure by lifting and relaxing the ribcage in rhythm with the diaphragm. Blood containing carbon dioxide enters the capillaries lining the alveoli.
The gas moves from the blood across a thin film of moisture and into the air sac.
The carbon dioxide is then breathed out
On inhalation, oxygen is drawn down into the alveoli where it passes into the blood using the same film of moisture.
The respiratory system also allows us to talk
Exhaled air runs over the vocal cords inside the throat. The sound of the voice depends on: how much air is being exhaled. Some common problems of the respiratory system include: – infection of the lung.
The nose and trachea The lungs The breathing muscles The exchange of gas Speech and the respiratory system the tension and length of the vocal cords the shape of the chest Problems of the respiratory system asthma – wheezing and breathlessness caused by a narrowing of the airways bronchitis – inflammation of the lung’s larger airways emphysema – disease of the alveoli (air sacs) of the lungs hay fever – an allergic reaction to pollen, dust or other irritants influenza – caused by viruses laryngitis – inflammation of the voice box (larynx) pneumonia Where to get help Your GP (doctor) Lung Foundation United States 1800 654 301.
Key Points
- main organ of the respiratory system is the lungs
- trachea is a hollow tube bolstered by rings of cartilage to prevent it from collapsing
- Some common problems of the respiratory system include: – infection of the lung