Difference between revisions of "Nasal Cavity - Anatomy & Physiology"

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[[Image:Nasal Cavities.jpg|thumb|right|300px|Nasal Cavities - Copyright David Bainbridge]]
 
==Introduction==
 
==Introduction==
[[Image:Nasal Cavities.jpg|thumb|right|300px|Nasal Cavities - Copyright David Bainbridge]]
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The respiratory tract begins with the ''nose'' which includes the external nose, internal nasal cavities and [[Paranasal Sinuses - Anatomy & Physiology|paranasal sinuses]].
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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 Overview - 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'']].
+
As well as being vital for transport of gases to the [[Cardiorespiratory System - Anatomy & Physiology#Lower Respiratory Tract|lower respiratory tract]], the nose is also the site for one of the special senses - [[Special Senses - Olfactory - Anatomy & Physiology|''Olfaction'']].
  
 
==Structure==
 
==Structure==
  
The nose consists of the external nares with nasal [[Cartilage - Anatomy & Physiology#Structure and Function of Cartilage|cartilages]], the nasal cavity (including the nasal meatus and conchae), and the [[Paranasal Sinuses - Anatomy & Physiology|paranasal sinuses]].
 
  
===Nasal cavity===
 
The nasal cavity is essentially a tube with a wall established by several [[Skull and Facial Muscles - Anatomy & Physiology#Bones of the Skull|bones of the skull]]. The borders of the nasal cavity are as follows:
 
  
'''Caudal''': The cribrifrom plate of the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale)|ethmoid bone]].
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*The nose consists of the external nares with nasal [[Bones and Cartilage - Anatomy & Physiology#Structure and Function of Cartilage|cartilages]], the nasal cavity (including the nasal meatus and conchae), and the [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]].
  
'''Ventral''': Continuous with the nasopharynx.
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*The nasal cavity is essentially a tube with a wall established by several [[Skull and Facial Muscles - Anatomy & Physiology#Bones of the Skull|bones of the skull]]. The borders of the nasal cavity are as follows:
  
'''Dorsal''': The maxilla and the palatine processes of the [[Skull and Facial Muscles - Anatomy & Physiology#Incisive Bone (os incisivium)|incisive bone]].
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- ''Caudal'': cribrifrom plate of the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale)|ethmoid bone]]
  
Rostrally, the median septum is a continuation of the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale)|ethmoid bone]]. The median septum is made up of [[Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]], and divides the nasal cavity into left and right halves.
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- ''Ventral'': continuous with the nasopharynx
  
[[Image:DogHeadDissection.jpg|right|thumb|250px|The nasal cavity can be seen filled with conchae in this photograph of a canine head. ©Nottingham 2008]]
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- ''Dorsal'': the maxilla and the palatine processes of the [[Skull and Facial Muscles - Anatomy & Physiology#Incisive Bone (os incisivium)|incisive bone]]
  
===Nasal conchae===
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*Rostrally, the median septum is a continuation of the [[Skull and Facial Muscles - Anatomy & Physiology#Ethmoid Bone (os ethmoidale)|ethmoid bone]]. The median septum is made up of [[Bones and Cartilage - Anatomy & Physiology#Hyaline Cartilage|hyaline cartilage]], and divides the nasal cavity into left and right halves.
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 and warm or cool the air that passes through.  
 
  
The conchae are [[Cartilage - Anatomy & Physiology#Types of Cartilage|cartilage]] 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 olfactory region, further.
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[[Image:DogHeadDissection.jpg|right|thumb|200px|The nasal cavity can be seen filled with conchae in this photograph of a canine head. ©Nottingham 2008]]
  
There are '''dorsal''' and '''ventral conchae''', the dorsal concha originating from the ethmoid bone and attaching to the maxilla, and the ventral conchae originating from the [[Skull and Facial Muscles - Anatomy & Physiology#Maxilla|maxilla]] and extending further into the nasal cavity. The conchae divide the nasal cavity into nasal ducts or '''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''':
+
*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 filtrate and warm or cool the air that passes through.  
  
'''Dorsal nasal meatus'''
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*The Conchae are cartilagenous or ossified scrolls which arise from the ''ethmoid bone''. They are covered with mucous membrane, under which is a layer of anastomosing blood vessels.
The passage between the roof of the nasal cavity and the dorsal nasal concha.  
+
The nasal conchae are more complex in animals with a better sense of smell, as they increase the surface area further.
  
'''Middle nasal meatus'''
+
*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.
Between the dorsal and ventral conchae, it communicates with the [[Paranasal Sinuses - Anatomy & Physiology|paranasal sinuses]].
 
  
'''Ventral nasal meatus'''
+
*The conchae divide the nasal cavity into nasal ducts or ''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:
The main pathway for airflow leading to the pharynx, it is positioned between the ventral nasal concha and the floor of the nasal cavity.
 
  
'''Common nasal meatus'''
+
- '''Dorsal nasal meatus''': the passage between the roof of the nasal cavity and the dorsal nasal concha
The longitudinal space on either side of the nasal septum.
 
  
The [[Paranasal Sinuses - Anatomy & Physiology|paranasal sinuses]] are extensions of the nasal cavity.
+
- '''Middle nasal meatus''': between the dorsal and ventral conchae, and communicates with the [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]].
  
==Function==
+
- '''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.
  
In addition to [[Nose - Anatomy & Physiology|olfaction]], the function of the nasal cavity is to modify the incoming air before it 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]]. The nasal cavity offers further protection via the sneezing reflex .
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- '''Common nasal meatus''': the longitudinal space on either side of the nasal septum.
  
==Species Differences==
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*The [[Paranasal sinuses - Anatomy & Physiology|Paranasal Sinuses]] are extensions of the nasal cavity.
  
The nasal cavity in the '''sheep''' is highly vascularised, with any damage to the epithelium resulting in severe [[Haemorrhage|haemorrhage]]. '''Cattle''' have a smaller nasal cavity compared to the horse. There are many variations to the entire [[Avian Respiration - Anatomy & Physiology|'''avian''' respiratory tract]]. The [[Respiration in Non-Homeotherms - Anatomy & Physiology|respiratory systems of non-homeotherms]] are also very different to that of mammals.
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==Function==
  
==Links==
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*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.
 +
*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.
 +
*The nasal cavity offer further protection via the Sneezing reflex .
  
Click here for information on [[Nasal Cavity - Pathology|pathology of the nasal cavity]].
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==Species Differences==
  
{{Template:Learning
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*The nasal cavity in the '''sheep''' is highly vascularised, with any damage to the epithelium resulting in severe [[General Pathology - Haemorrhage|haemorrhage]].
|dragster = [[Canine Head Radiographical Anatomy Resources (IV & V)|Canine Skull Anatomy - Nasal Chambers (V)]]
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*'''Cattle''' have a smaller nasal cavity compared to the horse.
|videos = [[Video: Equine head (sagittal section) potcast|Equine head (sagittal section) potcast]]<br>[[Video: Lateral surface of the head of the dog potcast 6|Lateral surface of the head of the dog potcast 6]]<br>[[Video: Lateral surface and sagittal section of the head of a sheep|Lateral surface and sagittal section of the head of a sheep]]
 
|Vetstream = [https://www.vetstream.com/canis/search?s=respiratory Respiratory diseases]
 
}}
 
  
{{review}}
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==References==
  
==Webinars==
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*{{citation|initiallast = Dyce|initialfirst = K.M|2last = Sack|2first = W.O|finallast = Wensing|finalfirst = C.J.G|year = 2002|title = Textbook of Veterinary Anatomy|ed =3rd|city = Philadelphia|pub = Saunders}}
<rss max="10" highlight="none">https://www.thewebinarvet.com/respiratory/webinars/feed</rss>
 
[[Category:Respiratory System - Anatomy & Physiology]]
 
[[Category:A&P Done]]
 

Revision as of 16:44, 14 August 2008

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Nasal Cavities - Copyright David Bainbridge

Introduction

The respiratory tract begins with the nose which includes the external nose, internal nasal cavities and paranasal sinuses. As well as being vital for transport of gases to the lower respiratory tract, the nose is also the site for one of the special senses - Olfaction.

Structure

  • The nose consists of the external nares with nasal cartilages, the nasal cavity (including the nasal meatus and conchae), and the paranasal sinuses.
  • The nasal cavity is essentially a tube with a wall established by several bones of the skull. The borders of the nasal cavity are as follows:

- Caudal: cribrifrom plate of the ethmoid bone

- Ventral: continuous with the nasopharynx

- Dorsal: the maxilla and the palatine processes of the incisive bone

  • 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.
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 olfactory mucus membranes and increasing the respiratory surface area, creating turbulence within the passing air. This helps to filtrate and warm or cool the air that passes through.
  • The Conchae are cartilagenous or ossified scrolls which arise from the 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 further.

  • There are dorsal and ventral conchae, the dorsal concha originating from the ethmoid bone and attaching to the maxilla, and the vental conchae originating from the maxilla and extending further into the nasal cavity.
  • The conchae divide the nasal cavity into nasal ducts or 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:

- Dorsal nasal meatus: the passage between the roof of the nasal cavity and the dorsal nasal concha

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

- 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.

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

Function

  • In addition to 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.
  • The nasal cavity offer further protection via the Sneezing reflex .

Species Differences

  • The nasal cavity in the sheep is highly vascularised, with any damage to the epithelium resulting in severe haemorrhage.
  • Cattle have a smaller nasal cavity compared to the horse.

References

  • Dyce, K.M., Sack, W.O. and Wensing, C.J.G. (2002) Textbook of Veterinary Anatomy. 3rd ed. Philadelphia: Saunders.