Changes

*Cranially the Costal and Mediastinal Pleura adjoin to form a 'dome' of pleura which extends cranially to the thoracic inlet. This is known as the '''Cupulae Pleurae'''. This region is only protected by soft tissue, and thus is vulnerable to injury.

*Cranially the Costal and Mediastinal Pleura adjoin to form a 'dome' of pleura which extends cranially to the thoracic inlet. This is known as the '''Cupulae Pleurae'''. This region is only protected by soft tissue, and thus is vulnerable to injury.

*Within the pleural sac encasing the right [[Lungs - Anatomy & Physiology|lung]], there is a fold which encases the Vena Cava. It is known as the '''Plica Venae Cavae'''.

*Within the pleural sac encasing the right [[Lungs - Anatomy & Physiology|lung]], there is a fold which encases the Vena Cava. It is known as the '''Plica Venae Cavae'''.

*The Pleural Membranes are larger than the [[Lungs - Anatomy & Physiology|lungs]] which they encase, thus there are areas where the facing surfaces of parietal pleura touch eachother. These are known as '''Pleural Recesses'''. One example is the '''Costodiaphragmatic Recess''', the space between the costal and [[Diaphragm - Anatomy & Physiology|diaphragm]]atic pleura. The volume of the recess varies to a point due to the phase of [[Ventilation - Anatomy & Physiology#Inspiration|inspiration]]/[[Ventilation - Anatomy & Physiology#Expiration|expiration]].

*The Pleural Membranes are larger than the [[Lungs - Anatomy & Physiology|lungs]] which they encase, thus there are areas where the facing surfaces of parietal pleura touch each other. These are known as '''Pleural Recesses'''. One example is the '''Costodiaphragmatic Recess''', the space between the costal and [[Diaphragm - Anatomy & Physiology|diaphragm]]atic pleura. The volume of the recess varies to a point due to the phase of [[Ventilation - Anatomy & Physiology#Inspiration|inspiration]]/[[Ventilation - Anatomy & Physiology#Expiration|expiration]].

===Pleural Membrane Function===

===Pleural Membrane Function===

*The Pleural Cavity is filled with a small amount of serous fluid which forms a thin film of liquid between the pleural layers. This is vital in that it prevents separation of the two pleural layers and lubricates the surface, so the [[Lungs - Anatomy & Physiology|lungs]] can move easily within the thoracic cavity.

*The Pleural Cavity is filled with a small amount of serous fluid which forms a thin film of liquid between the pleural layers. This is vital in that it prevents separation of the two pleural layers and lubricates the surface, so the [[Lungs - Anatomy & Physiology|lungs]] can move easily within the thoracic cavity.

*The Pleural Fluid also provides surface tension, keeping the [[Lungs - Anatomy & Physiology|lung]] suitably close to the wall of the thorax, despite the the lungs not being directly fixed to it. The pleurae thus allow the volume of the [[Lungs - Anatomy & Physiology|lungs]] to change with the volume of the thoracic cavity, enabling [[Ventilation - Anatomy & Physiology|Ventilation]].

*The Pleural Fluid also provides surface tension, keeping the [[Lungs - Anatomy & Physiology|lung]] suitably close to the wall of the thorax, despite the the lungs not being directly fixed to it. The pleurae thus allow the volume of the [[Lungs - Anatomy & Physiology|lungs]] to change with the volume of the thoracic cavity, enabling [[Ventilation - Anatomy & Physiology|ventilation]].

*The left and right pleural sacs are separate so that in the event of one being punctured, the other [[Lungs - Anatomy & Physiology|lung]] can continue to function effectively.

*The left and right pleural sacs are separate so that in the event of one being punctured, the other [[Lungs - Anatomy & Physiology|lung]] can continue to function effectively.

==Species Differences==

==Species Differences==

[[Image:Dogthorax1.jpg|right|thumb|350px|''The mediastinum is visible in this dog dissection, left lung removed. ©RVC 2008]]

[[Image:Dogthorax1.jpg|right|thumb|350px|''The mediastinum is visible in this dog dissection, left lung removed. ©RVC 2008]]

*In '''Cattle''' the [[Mediastinum - Anatomy & Physiology|Mediastinum]] is a tough membrane, in contrast to '''Horses, Dogs''' and '''Cats''' where it is rather thin and more delicate.

*In '''cattle''' the [[Mediastinum - Anatomy & Physiology|Mediastinum]] is a tough membrane, in contrast to '''horses, dogs''' and '''cats''' where it is rather thin and more delicate.

*Birds do not have a pleural cavity as [[Avian Respiration - Anatomy & Physiology|Avian lungs]] do not have the capacity to inflate.

*Birds do not have a pleural cavity as [[Avian Respiration - Anatomy & Physiology|Avian lungs]] do not have the capacity to inflate.

*The [[Respiration in Non-Homeotherms - Anatomy & Physiology|Respiratory Systems of non-Homeotherms]] are also very different to that of mammals.

*The [[Respiration in Non-Homeotherms - Anatomy & Physiology|Respiratory Systems of non-Homeotherms]] are also very different to that of mammals.