Breathing and Respiration


The Big Idea – Organisms are organised on a cellular basis and require a supply of energy or materials.

In this topic we look at the breathing system and how it works with the circulatory system to exchange gases for respiration. Do not confuse breathing with respiration. Breathing using lungs to exchange gases between the alveoli and blood. Oxygen is transported from the lungs to cells for respiration (the process of producing energy) and waste carbon dioxide is carried back and exhaled from the lungs. Plants and microorganisms do not require lungs to exchange gases for respiration. The gases can travel directly to and from the cells for respiration. 


The Essentials

You need to learn the parts of the breathing system and that breathing is controlled by the diaphragm moving up and down. As it moves down it decreases the pressure (more space for the air to fill) and air rushes into the lungs to fill the extra space. As the diaphragm move up the opposite happens

Breathing system

The alveoli are tiny sacs of lung tissue that connect the lungs to the blood supply. Alveoli are adapted to help exchange gases by having a LARGE SURFACE AREA and a THIN CELL WALL. Their function is to exchange the gases needed for and produced by RESPIRATION


Respiration is the process used by cells to provide energy.

Aerobic respiration uses oxygen and glucose (from the digestive system) to make energy and waste Carbon Dioxide which is transported back to the lungs.

In Humans we can make energy for short periods of time without oxygen. This is anaerobic respiration but this produces lactic acid which causes us pain ( a stitch when running) and we must switch back to using oxygen.

Some microbes such as yeast can use anaerobic respiration all the time and produce alcohol.

100% sheet Breathing

Deeper Understanding


Other Links

BBC Bitesize – Respiration and gas exchange

Crash Course – Breathing and Respiration

Review and Rate your Understanding

Can you…?

Explain the difference between breathing and Respiration

Explain the difference between aerobic and anaerobic respiration

List the parts of the breathing system in order

Name the gases exchanged by the alveoli

Have you learnt all the facts on the 100% sheet?

Have you completed the BBC Bitesize tutorial?

Have you been able to complete all the questions on the 100% sheet?

Let us know how you feel about this topic in the comments section below. Any questions you have, just ask.


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