Changes

==Structure==

==Structure==

[[Image:Nasal Cavities.jpg|thumb|right|150px|Nasal Cavities - Copyright David Bainbridge]]

[[Image:Nasal Cavities.jpg|thumb|right|250px|Nasal Cavities - Copyright David Bainbridge]]

*The nose consists of the external nares with nasal cartilages, the nasal cavity (including the nasal meatus and conchae), and the paranasal sinuses.

The nose consists of the external nares with nasal cartilages, the nasal cavity (including the nasal meatus and conchae), and the paranasal sinuses.

*Borders of the nasal cavity:

The borders of the nasal cavity are as follows:

- ''Caudal'': cribrifrom plate of the ethmoid bone

'''Caudal''': The cribrifrom plate of the ethmoid bone.

- ''Ventral'': continuous with the nasopharynx

'''Ventral''': Continuous with the nasopharynx.

- ''Dorsal'': the maxilla and the palatine processes of the incisive bones

'''Dorsal''': The maxilla and the palatine processes of the incisive bones.

*Rostrally, the median septum is a continuation of the ethmoid bone. The median septum is made up of hyaline cartilage, and divides the nasal cavity into left and right halves.

Rostrally, the median septum is a continuation of the ethmoid bone. The median septum is made up of hyaline cartilage, and divides the nasal cavity into left and right halves.

- '''Middle nasal meatus''': between the dorsal and ventral conchae, and communicates with the paranasal sinuses

Nasal conchae are turbinate bones that project into the nasal cavity. Their purpose is to increase the respiratory surface area, and to create turbulence within the passing air. This helps to filtrate and warm or cool the air that passes through. They are cartilagenous or ossified scrolls that are covered with mucous membrane, under which is a layer of anastomosing blood vessels.

- '''Ventral nasal meatus''': the main pathway for airflow leading to the pharynx, and is positioned between the ventral nasal concha and the floor of the nasal cavity

The nasal conchae are more complex in animals with a better sense of smell, as they increase the surface area further. There are dorsal and ventral conchae, the dorsal concha extending further into the nasal cavity. The conchae divide the nasal cavity into meatuses, which branch out from a common nasal meatus which is adjacent to the nasal septum. There are three nasal meatuses which branch from the common nasal meatus: '''dorsal''', '''middle''' and '''ventral''':

- '''Common nasal meatus''': the longitudinal space on either side of the nasal septum

'''Dorsal nasal meatus''': The passage between the roof of the nasal cavity and the dorsal nasal concha.

*The [[Paranasal Sinuses - Anatomy & Physiology|Paranasal Sinuses]] are extensions of the nasal cavity.

 

 

 

The [[Paranasal Sinuses - Anatomy & Physiology|paranasal sinuses]] are extensions of the nasal cavity.

==Function==

==Function==