Changes

==Inspiration==

==Inspiration==

*During Inspiration, the pressure within the [[Pleural cavity and membranes - Anatomy & Physiology|Pleural Cavity]] drops to less than the pressure of the external environment.  

*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 move caudally.

**[[Diaphragm - Anatomy & Physiology|Diaphragm]] - contracts - causing the dome to flatten and move caudally.

==Expiration==

==Expiration==

During Expiration, the pressure within the [[Pleural cavity and membranes - Anatomy & Physiology|Pleural Cavity]] increases to greater than that of the external environment, in order to expel air from the [[Lungs - Anatomy & Physiology|lungs]]. This is achieved by decreasing the lung volume, and is brought about by relaxation of Inspiratory Muscles:

During Expiration, the pressure within the [[Pleural Cavity and Membranes - Anatomy & Physiology|Pleural Cavity]] increases to greater than that of the external environment, in order to expel air from the [[Lungs - Anatomy & Physiology|lungs]]. This is achieved by decreasing the lung volume, and is brought about by relaxation of Inspiratory Muscles:

**Dome of the [[Diaphragm - Anatomy & Physiology|Diaphragm]] is pushed back by the intrathoracic pressure.

**Dome of the [[Diaphragm - Anatomy & Physiology|Diaphragm]] is pushed back by the intrathoracic pressure.

**[[Ribs and Sternum - Anatomy & Physiology|Ribs]] recoil back to their original position.

**[[Ribs and Sternum - Anatomy & Physiology|Ribs]] recoil back to their original position.