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WalesBiologyQuick questions
Unit 1: Respiration and circulation
Quick questions on The respiratory system and gas exchange - WJEC GCSE Biology (Unit 1)
2short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is inhalation?Show answer
The diaphragm contracts and flattens (moves down), and the external intercostal muscles contract, pulling the rib cage up and out. This increases the volume of the chest, which lowers the pressure inside the lungs below the outside air pressure, so air moves into the lungs.
What is exhalation?Show answer
The diaphragm relaxes and domes upward, and the intercostal muscles relax so the rib cage moves down and in. This decreases the volume of the chest, which raises the pressure inside the lungs, so air moves out.
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