Changes

===Guttural pouch===

===Guttural pouch===

**Horses

*Horses

***Diverticulum of the eustachian tube with a thin slit-like opening at the rostroventral aspect into the pharynx.

**Diverticulum of the eustachian tube with a thin slit-like opening at the rostroventral aspect into the pharynx.

***Mucous secretions drain out of the pouch when the horse lowers its head

**Mucous secretions drain out of the pouch when the horse lowers its head

***Lined by respiratory epithelium

**Lined by respiratory epithelium

***Bordered by glossopharyngeal, vagus, accessory and hypoglossal nerves; sympathetic trunk; internal and external carotid arteries

**Bordered by glossopharyngeal, vagus, accessory and hypoglossal nerves; sympathetic trunk; internal and external carotid arteries

**Pathology

*Pathology

***Mycotic infections eg: Aspergillus fumigatus

**Mycotic infections eg: Aspergillus fumigatus

****Bacterial infections eg: Streptococcus equi var. equi ('Strangles') or S.equi var zooepidemicus

***Bacterial infections eg: Streptococcus equi var. equi ('Strangles') or S.equi var zooepidemicus

***Tympany - associated with dysfunction of the pharyngotubal opening resulting from thickening (oedema, inflammation) or obstruction by a mucosal fold (eg: foals)

**Tympany - associated with dysfunction of the pharyngotubal opening resulting from thickening (oedema, inflammation) or obstruction by a mucosal fold (eg: foals)

==Defense mechanisms==

==Defense mechanisms==