Changes

The respiratory tract begins with the ''nose'' which includes the external nose, internal nasal cavities and [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]].

The respiratory tract begins with the ''nose'' which includes the external nose, internal nasal cavities and [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]].

As well as being vital for transport of gases to the [[Cardiorespiratory System - Anatomy & Physiology#Lower Respiratory Tract|lower respiratory tract]], the nasal cavity is also the site for one of the special senses - [[Special Senses - Olfactory - Anatomy & Physiology|''Olfaction'']].

As well as being vital for transport of gases to the [[Cardiorespiratory System - Anatomy & Physiology#Lower Respiratory Tract|lower respiratory tract]], the nasal cavity is also the site for one of the special senses - [[Nose - Anatomy & Physiology|''Olfaction'']].

==Structure==

==Structure==

[[Image:DogHeadDissection.jpg|right|thumb|200px|The nasal cavity can be seen filled with conchae in this photograph of a canine head. ©Nottingham 2008]]

[[Image:DogHeadDissection.jpg|right|thumb|200px|The nasal cavity can be seen filled with conchae in this photograph of a canine head. ©Nottingham 2008]]

*The nasal cavity is occupied to a large extent by '''''Nasal conchae'''''. These are turbinate bones which project into the nasal cavity with the purpose of supporting the [[Special Senses - Olfactory - Anatomy & Physiology|olfactory]] mucus membranes and increasing the respiratory surface area, creating turbulence within the passing air. This helps to filter, warm or cool the air that passes through.  

*The nasal cavity is occupied to a large extent by '''''Nasal conchae'''''. These are turbinate bones which project into the nasal cavity with the purpose of supporting the [[Nose - Anatomy & Physiology|olfactory]] mucus membranes and increasing the respiratory surface area, creating turbulence within the passing air. This helps to filter, warm or cool the air that passes through.  

*The Conchae are [[Bones and Cartilage - Anatomy & Physiology#Types of Cartilage|cartilage]]nous or ossified scrolls which arise from the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale|''ethmoid bone'']]. They are covered with mucous membrane, under which is a layer of anastomosing blood vessels.

*The Conchae are [[Bones and Cartilage - Anatomy & Physiology#Types of Cartilage|cartilage]]nous or ossified scrolls which arise from the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale|''ethmoid bone'']]. They are covered with mucous membrane, under which is a layer of anastomosing blood vessels.

The nasal conchae are more complex in animals with a better sense of smell, as they increase the surface area of the [[Special Senses - Olfactory - Anatomy & Physiology|Olfactory]] region, further.

The nasal conchae are more complex in animals with a better sense of smell, as they increase the surface area of the [[Nose - Anatomy & Physiology|Olfactory]] region, further.

*There are dorsal and ventral conchae, the dorsal concha originating from the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale)|ethmoid bone]] and attaching to the maxilla, and the vental conchae originating from the [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilla]] and extending further into the nasal cavity.

*There are dorsal and ventral conchae, the dorsal concha originating from the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale)|ethmoid bone]] and attaching to the maxilla, and the vental conchae originating from the [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilla]] and extending further into the nasal cavity.

==Function==

==Function==

*In addition to [[Special Senses - Olfactory - Anatomy & Physiology|Olfaction,]] the function of the nasal cavity is to modify the incoming air before is is transported further down the respiratory tract.  

*In addition to [[Nose - Anatomy & Physiology|Olfaction,]] the function of the nasal cavity is to modify the incoming air before is is transported further down the respiratory tract.  

*Air is warmed as it passes over the highly vascularised mucosal surfaces of the conchae, humidified by the evaporation from nasal secretion and cleaned as it contacts the secretion from mucus glands within the nasal cavity. The mucus secreted from the glands traps particles and cilia transport them down to the pharynx for swallowing, this process is known as the [[Respiratory Epithelium - Anatomy & Physiology#Mucociliary Escalator|Mucociliary Escalator]].

*Air is warmed as it passes over the highly vascularised mucosal surfaces of the conchae, humidified by the evaporation from nasal secretion and cleaned as it contacts the secretion from mucus glands within the nasal cavity. The mucus secreted from the glands traps particles and cilia transport them down to the pharynx for swallowing, this process is known as the [[Respiratory Epithelium - Anatomy & Physiology#Mucociliary Escalator|Mucociliary Escalator]].

*The nasal cavity offers further protection via the Sneezing reflex .

*The nasal cavity offers further protection via the Sneezing reflex .