Changes

Click here for information on the [[Vomeronasal Organ]].

Click here for information on the [[Vomeronasal Organ]].

==Histology==

===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. The first part of the [[Equine Upper Respiratory Tract - Horse Anatomy#Nasal Cavity|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 [[Equine Upper Respiratory Tract - Horse Anatomy#Nasal Cavity|nasal cavity]]. The upper part of the [[Equine Upper Respiratory Tract - Horse Anatomy#Nasal Cavity|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.

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 [[Equine Upper Respiratory Tract - Horse Anatomy#Nasal Cavity|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 [[Equine Upper Respiratory Tract - Horse Anatomy#Nasal Cavity|nasal cavity]]. The upper part of the [[Equine Upper Respiratory Tract - Horse Anatomy#Nasal Cavity|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.