Nose - Anatomy & Physiology - Revision history

Bara at 15:13, 28 June 2012

2012-06-28T15:13:06Z

Bara at 15:51, 10 January 2011

2011-01-10T15:51:45Z

Aimee.e.hicks: /* Links */

2010-12-23T16:35:58Z

Links

Aimee.e.hicks: /* Species Differences */

2010-12-23T16:34:53Z

Species Differences

Aimee.e.hicks: /* Histology */

2010-12-23T16:34:40Z

Histology

Aimee.e.hicks: /* Vomeronasal Organ */

2010-12-23T16:32:07Z

Vomeronasal Organ

Aimee.e.hicks: /* Central Olfactory Pathways */

2010-12-23T16:31:26Z

Central Olfactory Pathways

Aimee.e.hicks: /* Innervation */

2010-12-23T16:30:08Z

Innervation

Aimee.e.hicks: /* Vasculature */

2010-12-23T16:29:17Z

Vasculature

Aimee.e.hicks: /* Function */

2010-12-23T16:28:06Z

Function

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 ==Introduction==
 Olfaction is the sense of smell, which is the ability to perceive and distinguish odours. Most '''mammals''' have a good sense of smell, but most '''birds''' generally do not. The sense of smell is well-developed in '''carnivores''' (predators) and '''ungulates''' (prey). '''Fish''' also have a fairly well-developed sense of smell. Olfactory and gustatory receptors can combine to contribute to flavour.
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+{{OpenPages}}
 [[Category:Respiratory System - Anatomy & Physiology]]
 [[Category:Special Senses - Anatomy & Physiology]]
 [[Category:A&P Done]]

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 '''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.
+'''Ventral nasal meatus''': The main pathway for airflow leading to the [[Pharynx - Anatomy & Physiology|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.
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 ==Links==
-Click here for more information on the [[Nasal Cavity - Anatomy & Physiology|nasal Cavity]].
+Click here for more information on the [[Nasal Cavity - Anatomy & Physiology|Nasal Cavity]].
 Click here for more information on [[Diseases of the nasal cavity and sinuses|diseases of the nasal cavity and sinuses]].
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 [[Category:Respiratory System - Anatomy & Physiology]]
 [[Category:Special Senses - Anatomy & Physiology]]
-[[Category:Image Review]]
+[[Category:A&P Done]]

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 ==Links==
-[[Nasal Cavity - Anatomy & Physiology|Nasal Cavity]]
+Click here for more information on the [[Nasal Cavity - Anatomy & Physiology|nasal Cavity]].
-[[Diseases of the nasal cavity and sinuses|Diseases of the nasal cavity and sinuses]]
+Click here for more information on [[Diseases of the nasal cavity and sinuses|diseases of the nasal cavity and sinuses]].
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 [[Category:Special Senses - Anatomy & Physiology]]
 [[Category:Image Review]]
-[[Category:To Do - A&P]]
+[[Category:To Do - AimeeHicks]][[Category:To Do - Review]]

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 ==Species Differences==
-*Those animals with a better sense of smell have a greater vascular supply to the mucosa of the dorsal nasal conchae.
+Those animals with a better sense of smell have a greater vascular supply to the mucosa of the dorsal nasal conchae.
 ==Links==

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 ==Histology==
-*Olfactory epithelium is made up of olfactory cells, sustentacular cells and basal cells. The olfactory axons  and olfactory glands are present in the lamina propria.
+Olfactory epithelium is made up of '''olfactory cells''', '''sustentacular cells''' and '''basal cells'''. The olfactory axons  and olfactory glands are present in the lamina propria. The first part of the nasal cavity, from the nostrils, is lined by keratinised stratified squamous epithelium. Sebaceous glands and hairs are also present in this region. The hairs function to keep dust out of the nasal cavity. The upper part of the nasal cavity is also lined by stratified squamous epithelium, but it is no longer keratinised. The epithelium then becomes pseudostratified columnar, and is ciliated. This is typical of the respiratory system, so this type of epithelium may also be known as respiratory epithelium. Goblet cells, which produce mucous, are present in this region of the nasal cavity. Mucous and serous glands are present in the connective tissue, the lamina propria, which lies underneath the epithelium that covers the nasal conchae. The olfactory region of the nasal cavity is formed by the membrane covering the dorsal nasal conchae. Cilia in this region are formed from olfactory cells, although they are non-motile. It is the membrane that covers these cilia that contains the olfactory receptors that are sensitive to smell, after the odours have been dissolved in the serous membrane covering the epithelium. The axons of these receptors bundle together within the lamina propria. The olfactory cells gain mechanical and metabolic support from the sustentacular cells.
 ==Species Differences==

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 The olfactory receptors are embedded in the mucous membrane within the nasal cavity. They are bipolar neurones, and are covered with cilia (non-motile). It is thought that these cilia contain the active sites for the olfactory transduction process. The axons from the olfactory receptors join together and become the olfactory nerve ([[Cranial Nerves - Anatomy & Physiology|CN I]]). The axons pass through the perforations in the cribriform plate of the ethmoid bone, and enter the olfactory bulb. Once the axons have entered the olfactory bulb, the olfactory nerve synapses on mitral cells. The axons from these cells then project into the olfactory cortex of the cerebral hemispheres, via the olfactory tract. The olfactory cortex is the only region within the cerebral hemispheres that receives direct sensory input without any information first passing through the thalamus. This is because the olfactory system evolved before the thalamus.
-==[[Vomeronasal Organ]]==
+==Vomeronasal Organ==
 ==Histology==

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 ==Central Olfactory Pathways==
-[[Image:Central Olfactory Pathways.jpg|thumb|right|150px|Central Olfactory Pathways - Copyright David Bainbridge]]
+[[Image:Central Olfactory Pathways.jpg|thumb|right|250px|Central Olfactory Pathways - Copyright David Bainbridge]]
-*The olfactory receptors are embedded in the mucous membrane within the nasal cavity. They are bipolar neurones, and are covered with cilia (non-motile).
+The olfactory receptors are embedded in the mucous membrane within the nasal cavity. They are bipolar neurones, and are covered with cilia (non-motile). It is thought that these cilia contain the active sites for the olfactory transduction process. The axons from the olfactory receptors join together and become the olfactory nerve ([[Cranial Nerves - Anatomy & Physiology|CN I]]). The axons pass through the perforations in the cribriform plate of the ethmoid bone, and enter the olfactory bulb. Once the axons have entered the olfactory bulb, the olfactory nerve synapses on mitral cells. The axons from these cells then project into the olfactory cortex of the cerebral hemispheres, via the olfactory tract. The olfactory cortex is the only region within the cerebral hemispheres that receives direct sensory input without any information first passing through the thalamus. This is because the olfactory system evolved before the thalamus.
 ==[[Vomeronasal Organ]]==

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 ==Innervation==
-*Sensory innervation is provided by the olfactory nerve ([[Cranial Nerves - Anatomy & Physiology|CN I]]).
+Sensory innervation is provided by the '''olfactory nerve''' ([[Cranial Nerves - Anatomy & Physiology|CN I]]).
 ==Central Olfactory Pathways==

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 ==Vasculature==
-*There is a dense network of blood vessels supplying the nasal mucosa.
+There is a dense network of blood vessels supplying the nasal mucosa. The '''sphenopalatine artery''' supplies the nasal cavity. The lateral and dorsal '''nasal arteries''', which are branches of the facial artery, itself a branch of the '''external carotid artery''', supply the nose. The '''infraorbital artery''' also supplies the nose.
 ==Innervation==

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 ==Function==
-[[Image:Olfactory Epithelium.jpg|thumb|right|150px|Olfactory Epithelium - Copyright David Bainbridge]]
+[[Image:Olfactory Epithelium.jpg|thumb|right|250px|Olfactory Epithelium - Copyright David Bainbridge]]
-*Olfactory sensory neurones are present in the olfactory epithelium.
+The '''olfactory sensory neurones''' are present in the olfactory epithelium. Those animals with a better sense of smell have more highly innervated olfactory epithelium. It is the mucous membrane of the dorsal nasal conchae that is sensitive to smell. Here, odourants dissolve in the mucous membrane, and it is these odourants that are recognised by the olfactory sensory receptors. '''Sensory cilia''', that are present on the surface of the olfactory receptors, project into the film of mucous. The mucous also contains antibodies, to prevent infection. This is because the olfactory neurones provide a direct passage, via the olfactory nerve ([[Cranial Nerves - Anatomy & Physiology|CN I]]), to the brain.
 ==Vasculature==