GCSE Biology B5 Gas Exchange

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2.38 Understand the role of diffusion in gas exchange

In humans, gas exchange occurs in the lungs, Oxygen is DIFFUSED from the alveoli into the blood, and Carbon dioxide is diffused out of the blood into the alveoli which is then exhaled.

Exhaling is a form of excretion 

2.44 Describe the structure of the thorax, including the ribs, intercostal muscles , diaphragm, trachea, bronchi, bronchioles, alveoli and pleuralmembranes


2.45 Understand the role of intercostal muscles and the diaphragm, in ventilation.

During Inhalation :

Your diaphragm contracts and flattens making a larger surface area 

Your external intercostal muscles contract whereas your internal intercostal muscles relax

Your ribs move upward and outwards

The volume of your thoracic cavity increases

The expansion of your lungs causes low…


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