*During Inspiration, the pressure within the [[Pleural cavity and membranes - Anatomy & Physiology|Pleural Cavity]] drops to less that the pressure of the external environment.
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*During Inspiration, the pressure within the [[Pleural cavity and membranes - Anatomy & Physiology|Pleural Cavity]] drops to less than the pressure of the external environment.
*This is achieved by increasing the [[Lungs - Anatomy & Physiology|lung]] volume, brought about by the Inspiratory Muscles:
*This is achieved by increasing the [[Lungs - Anatomy & Physiology|lung]] volume, brought about by the Inspiratory Muscles:
**[[Diaphragm - Anatomy & Physiology|Diaphragm]] - contracts - causing the dome to flatten and moe caudally.
**[[Diaphragm - Anatomy & Physiology|Diaphragm]] - contracts - causing the dome to flatten and moe caudally.