Blood and the respiratory system
Blood and the respiratory system

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Blood and the respiratory system

1 Respiratory structures and ventilation

Oxygen (O2) is a critical component for human life and is needed for the homeostatic maintenance of all the body’s tissues and organs.

Cellular respiration, the process by which energy is made, is dependent on a constant supply of O2. At the same time, this process generates the waste product carbon dioxide (CO2), which must be continuously removed. The process by which O2 and CO2 are exchanged between the body and the environment is termed external respiration. On average, an adult takes between 12 and 18 breaths a minute at rest, exchanging more than 8000 litres of air per day.

Using the glossary

This course includes a glossary, as demonstrated by the terms ‘cellular respiration’ and ‘external respiration’ highlighted in the paragraph above. You can hover over these for a preview, and click on the words to be taken to the full definition in the glossary.

Over the course of this section, you will learn how physical forces such as pressure, surface tension, resistance and compliance determine the amount of airflow through the respiratory and conduction zones of the respiratory system.


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