Inhaling and exhaling 0.0 / 5 ? BiologyCellular processes and structureASOCR Created by: Steff06Created on: 11-04-16 11:36 What is the 1st step in inhalation? Diaphragm contracts to become flatter and pushes digestive organs down. 1 of 10 What happens after the diaphragm contracts? External intercostal muscles contract to raise ribs. 2 of 10 What happens after ribs are raised? Volume of chest cavity increases. 3 of 10 What is the next stage after the volume of chest cavity increases? Pressure in chest cavity drops below atmospheric pressure. 4 of 10 What happens after the pressure drops? Air moves into the lungs. 5 of 10 What is the 1st stage in exhalation? Diaphragm relaxes and is pushed up by displaced organs underneath. 6 of 10 What happens after the diaphragm relaxes? External intercostal muscles relax and ribs fall. 7 of 10 What happens after intercostal muscles relax? Volume of chest cavity decreases. 8 of 10 What is the next stage after the volume of chest cavity decreases? Pressure in lungs increases and rises above atmospheric pressure. 9 of 10 What happens after the pressure in the lungs increases? Air moves out of the lungs. 10 of 10
Gaseous exchange occurs across the walls of the alveoli. Explain why they contain elastic fibres. 0.0 / 5
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