Respiratory system

What does the respiratory system do?

The respiratory system provides oxygen to the body, and removes the waste gas carbon dioxide.

As well as needing lungs and airways to breathe, we also need a well-functioning nervous system (brain and spinal cord) and breathing muscles (the diaphragm and the muscles between the ribs, the intercostals).

Problems with the respiratory system

There are a few different reasons why someone may have problems breathing normally. Abnormal or inadequate breathing can happen as a result of:

  • a problem with the nervous system, for example from a head injury or a spinal injury
  • oxygen not being absorbed properly, for example from fluid in the lungs
  • an obstruction to the flow of air when breathing in or out, for example from asthma
  • damage to the rib cage, for example from a car accident
  • pain, which makes taking a normal breath difficult.

Respiratory failure

Some medical conditions can result in respiratory failure. People with respiratory failure need intensive treatment and so need to be admitted to the intensive care unit (ICU), where they can be closely monitored and treated.

Intensive treatment provided by the ICU includes ventilation support (help with breathing), through the use of oxygen masks, continuous positive airway pressure (CPAP) or via a breathing tube (endotracheal tube) and ventilator (breathing machine). (See Breathing support and Equipment.)


The information on this page is general in nature and cannot reflect individual patient variation. It reflects Australian intensive care practice, which may differ from that in other countries. It is intended as a supplement to the more specific information provided by the doctors and nurses caring for your loved one. ICNSW attests to the accuracy of the information contained here but takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.