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[[Image:Vestibular Receptors and Balance.jpg|thumb|right|150px|Vestibular Receptors and Balance - Copyright David Bainbridge]]
 
[[Image:Vestibular Receptors and Balance.jpg|thumb|right|150px|Vestibular Receptors and Balance - Copyright David Bainbridge]]
 
The vestibular sense is rather more unconscious than that of hearing. The '''vestibular labyrinth''', that is contained within the '''bony labyrinth''' of the '''inner ear''' is the part of the ear that is involved with the vestibular sense - balance. The vestibular labyrinth contains the '''saccule''', the '''utricle''' and the '''semicircular ducts''' - the semicircular ducts being housed within the semicircular canals.  There are sensory hair cells within the vestibular labyrinth, similar to those in the other regions of the inner ear, which detect movement. However, these sensory hair cells are lodged in the '''ampullary cupulae''' or in '''otoliths''' (minute calcareous particles), rather than in the tectorial membrane as in the rest of the ear. The '''ampulla''' is a swelling at the base of the semicircular ducts. The sensory hair cells project upwards from the ampulla into the '''cupula''', which is a gelatinous mass. The ampullary cupulae detect flow around the semicircular canals, which are filled with '''endolymph''', and there is an inertia of fluid for detection of '''angular acceleration'''. Angular acceleration is the detection of motion of the head in any direction.  '''Otoliths''' are denser than endolymph - they are calcareous and crystalline. They are contained within the '''maculae''', and detect '''gravity and linear acceleration'''. Linear acceleration is the detection of motion along a line, for example when the horse leans to one side. Movement of the sensory hair cells triggers impulses, which are carried by the vestibular portion of the vestibulocochlear nerve ([[Equine Cranial Nerves - Horse Anatomy#Vestibulocochlear Nerve (VIII)|CN VIII]]).
 
The vestibular sense is rather more unconscious than that of hearing. The '''vestibular labyrinth''', that is contained within the '''bony labyrinth''' of the '''inner ear''' is the part of the ear that is involved with the vestibular sense - balance. The vestibular labyrinth contains the '''saccule''', the '''utricle''' and the '''semicircular ducts''' - the semicircular ducts being housed within the semicircular canals.  There are sensory hair cells within the vestibular labyrinth, similar to those in the other regions of the inner ear, which detect movement. However, these sensory hair cells are lodged in the '''ampullary cupulae''' or in '''otoliths''' (minute calcareous particles), rather than in the tectorial membrane as in the rest of the ear. The '''ampulla''' is a swelling at the base of the semicircular ducts. The sensory hair cells project upwards from the ampulla into the '''cupula''', which is a gelatinous mass. The ampullary cupulae detect flow around the semicircular canals, which are filled with '''endolymph''', and there is an inertia of fluid for detection of '''angular acceleration'''. Angular acceleration is the detection of motion of the head in any direction.  '''Otoliths''' are denser than endolymph - they are calcareous and crystalline. They are contained within the '''maculae''', and detect '''gravity and linear acceleration'''. Linear acceleration is the detection of motion along a line, for example when the horse leans to one side. Movement of the sensory hair cells triggers impulses, which are carried by the vestibular portion of the vestibulocochlear nerve ([[Equine Cranial Nerves - Horse Anatomy#Vestibulocochlear Nerve (VIII)|CN VIII]]).
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===Central Vestibular Pathways===
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[[Image:Central Vestibular Pathways.jpg|thumb|right|150px|Central Vestibular Pathways - Copyright David Bainbridge]]
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The sensory hair cells produce signals, which are carried by the vestibulocochlear nerve ([[Equine Cranial Nerves - Horse Anatomy#Vestibulocochlear Nerve (VIII)|CN VIII]]) first of all through the '''bipolar vestibular ganglion cells'''. Most nerve fibres that have come from the hair cells terminate in the '''vestibular nuclei''', which are located in the fourth ventricle of the [[Equine Brain - Horse Anatomy#Forebrain|cerebral cortex]]. After entering the vestibular nuclei, some of the processes of the nerve fibres divide into '''ascending and descending branches'''. Some processes pass directly into the [[Equine Brain - Horse Anatomy#Hindbrain|cerebellum]].
    
==Gustatory System==
 
==Gustatory System==
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