Changes

==Central Auditory Pathways==

==Central Auditory Pathways==

[[Image:Central Auditory Pathway.jpg|thumb|right|150px|Central Auditory Pathway - Copyright David Bainbridge]]

[[Image:Central Auditory Pathway.jpg|thumb|right|150px|Central Auditory Pathway - Copyright David Bainbridge]]

*The signal that has been created from the sound waves that were picked up by the ear, is carried to the brain by the vestibulocochlear nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VIII]]), which synapses in the cochlear nucleus.

*The signal that has been created from the sound waves that were picked up by the ear, is carried to the brain by the vestibulocochlear nerve ([[Cranial Nerves - Anatomy & Physiology|CN VIII]]), which synapses in the cochlear nucleus.

*From here, the auditory information is then split.

*From here, the auditory information is then split.

*Those nerve fibres that travel to the ventral cochlear nuclear synapse on their target cells. The ventral cochlear nuclear cells then project to a group of cells within the medulla, called the superior olive nucleus. It is here that the timing and loudness of the sound that was picked up in each ear is compared, allowing determination of the direction that the sound came from. This information is then transferred via the lateral lemniscus to the inferior colliculus.

*Those nerve fibres that travel to the ventral cochlear nuclear synapse on their target cells. The ventral cochlear nuclear cells then project to a group of cells within the medulla, called the superior olive nucleus. It is here that the timing and loudness of the sound that was picked up in each ear is compared, allowing determination of the direction that the sound came from. This information is then transferred via the lateral lemniscus to the inferior colliculus.

*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.

*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 you lean to one side.

*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 you lean to one side.

*Movement of the sensory hair cells triggers impulses, which are carried by the vestibular portion of the vestibulocochlear nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VIII]]).

*Movement of the sensory hair cells triggers impulses, which are carried by the vestibular portion of the vestibulocochlear nerve ([[Cranial Nerves - Anatomy & Physiology|CN VIII]]).

==Central Vestibular Pathways==

==Central Vestibular Pathways==

[[Image:Central Vestibular Pathways.jpg|thumb|right|150px|Central Vestibular Pathways - Copyright David Bainbridge]]

[[Image:Central Vestibular Pathways.jpg|thumb|right|150px|Central Vestibular Pathways - Copyright David Bainbridge]]

*The sensory hair cells produce signals, which are carried by the vestibulocochlear nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VIII]]) first of all through the bipolar vestibular ganglion cells.

*The sensory hair cells produce signals, which are carried by the vestibulocochlear nerve ([[Cranial Nerves - Anatomy & Physiology|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 cerebral cortex.

*Most nerve fibres that have come from the hair cells terminate in the vestibular nuclei, which are located in the fourth ventricle of the 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 cerbellum.

*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 cerbellum.

Sensory innervation to the outer ear:

Sensory innervation to the outer ear:

*Ce2 (second cervical spinal nerve) to medial pinna

*Ce2 (second cervical spinal nerve) to medial pinna

*Auriculopalpebral branch of trigeminal nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN V]]) to most of the lateral pinna

*Auriculopalpebral branch of trigeminal nerve ([[Cranial Nerves - Anatomy & Physiology|CN V]]) to most of the lateral pinna

*Facial ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VII]]) and vagus nerves ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN X]]) via small auricular branches to pinna

*Facial ([[Cranial Nerves - Anatomy & Physiology|CN VII]]) and vagus nerves ([[Cranial Nerves - Anatomy & Physiology|CN X]]) via small auricular branches to pinna

Sensory innervation to the inner parts of the ear is provided by the vestibulocochlear nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VIII]]).

Sensory innervation to the inner parts of the ear is provided by the vestibulocochlear nerve ([[Cranial Nerves - Anatomy & Physiology|CN VIII]]).

Innervation to the muscles of the middle ear:

Innervation to the muscles of the middle ear:

*The tensor tympani muscle is innervated by the pterygoid nerve, which is a branch of the mandibular nerve, itself being the third branch of the trigeminal nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN V]]).

*The tensor tympani muscle is innervated by the pterygoid nerve, which is a branch of the mandibular nerve, itself being the third branch of the trigeminal nerve ([[Cranial Nerves - Anatomy & Physiology|CN V]]).

*The stapedius muscle is innervated by the facial nerve ([[Nervous System - CNS - Anatomy & Physiology#Innervation - Cranial Nerves|CN VII]]).

*The stapedius muscle is innervated by the facial nerve ([[Cranial Nerves - Anatomy & Physiology|CN VII]]).

==Equine Guttural Pouch==

==Equine Guttural Pouch==