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Cranial Nerves - Anatomy & Physiology (view source)
Revision as of 10:55, 11 August 2011
, 10:55, 11 August 2011→Vestibulocochlear (III)
The optic nerve can be examined clinically via a menace response and anopsia (loss of vision) can be seen in injury.
The optic nerve can be examined clinically via a menace response and anopsia (loss of vision) can be seen in injury.
===Vestibulocochlear (III)===
===Oculomotor nerve (III)===
The oculomotor nerve is part of the group of cranial nerves responsible for innervating the muscles of the head. The nerves originate from the ventral [[Midbrain_-_Anatomy_%26_Physiology|midbrain]] and is a motor nerve. It is composed of '''general somatic efferent fibres''' and '''general visceral efferent fibres'''. The general somatic efferent fibres of the oculomotor nerve are responsible for the motor function of four of the six external muscles of the eyeball; the 'dorsal rectus', 'medial rectus', 'ventral rectus', 'ventral oblique' and 'levator of the upper eyelid'. The general visceral efferent fibres of the oculomotor nerve are responsible for the control of pupil diameter and therefore control the 'spincter pupillae' muscle and the 'ciliaris' muscle.
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The oculomotor nerve has a pre-ganglionic nucleus in the midbrain and the nerve passes through the '''orbital fissure''', along with the trochlear, abducens and opthalmic branch (V1) of the trigeminal nerve. It synapses in the ciliary ganglion of the eye. During a clinical examination, horizontal eye movements (strabismus) or an abscent pupillary light reflex (PLR) may indicate a problem.
===Trochlear nerve (IV)===
===Vestibulocochlear nerve (VIII)===
The vestibulocochlear nerve is part of the special senses group of cranial nerves and is made up of two components; the vestibular nerve and the cochlear nerve. The vestibular nerve is responsible for balance whilst the cochlear nerve is responsible for hearing. The nerves send impulses from the inner ear which contains the [[Ear_-_Anatomy_%26_Physiology#Vestibular_Receptors_and_Balance|vestibular apparatus]] and [[Ear_-_Anatomy_%26_Physiology#The_Cochlea|cochlear]]. The vestibulocochlear nerve is a sensory nerve made up of '''special somatic afferent fibres'''. It passes through the '''internal acoustic meatus''' and into the '''petrosal bone'''. The facial nerve also takes this route.
The vestibulocochlear nerve is part of the special senses group of cranial nerves and is made up of two components; the vestibular nerve and the cochlear nerve. The vestibular nerve is responsible for balance whilst the cochlear nerve is responsible for hearing. The nerves send impulses from the inner ear which contains the [[Ear_-_Anatomy_%26_Physiology#Vestibular_Receptors_and_Balance|vestibular apparatus]] and [[Ear_-_Anatomy_%26_Physiology#The_Cochlea|cochlear]]. The vestibulocochlear nerve is a sensory nerve made up of '''special somatic afferent fibres'''. It passes through the '''internal acoustic meatus''' and into the '''petrosal bone'''. The facial nerve also takes this route.
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