Flashcards
cranial nerves 2005
Cards in this deck (20)
- 1summary of cranial nerves- all cranial nerves apart from the optic nerve are part of the PNS
- CNs are numbered in rostro-caudal sequence of their origins from the brain
- Arise from the brainstem (with the exception of the olfactory and optic nerves)
- arise from anterior (basal) surface of the brain (with the exception of the trochlear nerve) - 2Afferent sensory fibres - INPUT- General somatic afferent (GSA): similar to information carried in the dorsal roots of the spinal cord (touch, pain, temp, itch)
- Special somatic afferent (SSA): special senses - vision, hearing, balance
- General visceral afferent (GVA): sensory feedback from organs or glands
- Special Visceral afferent (SVA): found in organs of special chemical sensing (taste and olfaction) - 3Efferent motor fibres - OUTPUT- General somatic efferent (GSE): like ventral roots, motor fibres that innervate skeletal muscle of the head and neck
- General visceral efferent (GVE): fibres that belong to the autonomic NS and supply the parasympathetic ganglia
- Special visceral efferent (SVE): motor fibres that supply muscles of the pharyngeal arches, also referred to sometimes are branchial efferents - 412 cranial nerves in order 1-12olfactory
optic
occulomotor
trochlear
trigeminal
abducens
facial
vestibulocochlear
glossopharyngeal
vagus
accessory
hypoglossal - 5only 4 cranial nerves contain parasympathetic fibres GVEIII, VII, IX, X
occulomotor, facial, glossopharyngeal, and vagus
Fibres from these nuclei synapse on parasympathetic head ganglia - 6describe the olfactory nerve- centrally projecting nerve fibres originate from the nasal olfactory epithelium
- olfactory nerve fibres project through the cribriform plate and synapse on the olfactory bulb
- second order neurones in the olfactory bulb connect via the olfactory tract to the uncus, which contains the primary olfactory cortex
- there is no thalamic relay in olfaction
- the two olfactory bulbs are connected by the anterior commissure - 7Describe the occulomotor nerve- a motor nerve that originates in the midbrain
- innervates most extraocular eye muscles, an upper eyelid muscle and 2 smooth intrinsic eye muscles (ciliary muscle and circular sphincter pupillae)
Damage results in opthalomoplegia with eye deviated down and out - 8the trochlear nerve- a motor nerve
- the only nerve to originate from the dorsal part of the midbrain
- innervates the superior oblique eye muscles, moving the eye down and out
- damage results in an inability to rotate the eye inferolaterally, and gaze is up and in - 9the Trigeminal nerve- is both a sensory and motor nerve
- originates in the pons
- three major branches are the opthalmic, maxillary, and mandibular nerves
- it is the general sensory nerve of the face, rostral tongue, all teeth and bony skull, and most of the dura mater
- motor component it supplies all muscles of mastication - 10describe division 1 (the opthalmic nerve) of the trigeminal nerve- sensory only
- supplies the skin of the forehead, eyelids, eyebrow and nose. The eye and afferent sensory component of the corneal/blink reflex. And the mucous membrane of the upper nasal cavity
- branches into the frontal, nasociliary and lacrimal nerves in the orbit - 11describe division 2 ( the maxillary nerve) of the trigeminal nerve- sensory only
- supplies the skin of the middle face and teeth of upper jaw and maxillary sinus - 12describe division 3 (the mandibular nerve) of the trigeminal nerve- a MIXED nerve:
- sensory: skin of lower face, teeth of lower jaw, general sensation of anterior 2/3 of tongue NOT TASTE
- Motor: muscles of mastication, middle ear, oral diaphragm, and palate - 13describe the abducens nerve- is a motor nerve
- originates on border of pons and medulla
- innervates lateral rectus eye muscle which abducts the eye - 14describe the facial nerve- a mixed nerve
- motor: muscles of facial expression and muscles of scalp, post. belly of digrastric, stylohyoid and stapedius. Also contributes to corneal/blink reflex. has 5 major branches supplying muscles of facial expression (buccal, cervical, marginal mandibular, temporal, zygomatic)
- special visceral afferents: taste from anterior 2/3 of tongue
- parasympathetic: tears and saliva - 15describe the vestibulocochlear nerve- vestibular nerve = position of head in relation to movement and gravity
- cochlear nerve = hearing
- the vestibular nerve receives input from 3 semicircular canals, the utricle and the sacule
- utricle and saccule detect gravity and linear acceleration
- semicircular canals detect angular acceleration - 16the auditory pathway- 3 relay nuclei prior to thalamic target: cochlear nucleus, superior olivary complex, inferior colliculus
- the superior olivary complex aids with spatial localisation of incoming sounds from the horizontal plane by comparing differences in the timing or stimulus intensity between the L and R ears - 17the glossopharyngeal nerve- a mixed nerve originating in the medulla
- special sensation: taste in dorsal 1/3 tongue
- general sensation: intra oral, pharynx, dorsal 1/3 tongue
- motor: supplies stylopharyngeus
- parasympathetic: inferior salivary nucleus to parotid salivary gland
- carries afferent (sensory) component of the pharyngeal gag reflex - 18the vagus nerve- the only cranial nerve that extends beyond the head and neck
- a mixed nerve
- general visceral sensory: receptors in the walls of the viscera
- special visceral sensory: taste from pharyngeal area
- motor: muscles of the larynx, pharynx, upper esophagus
- parasympathetic: all visceral organs of the neck, thorax, upper abdomen nd parts of the intestine that are derived from the foregut and midgut
- carries the efferent (motor) component of the pharyngeal gag reflex - 19the accessory nerve- a pure motor nerve with 2 structural parts
- the cranial part merges with the vagus
- a spinal part
- innervates trapezius and sternocleidomastoid
- damage results in ipsilateral shoulder sags and cannot be raised (trap) head movement to the opposite side is limited (sterno) - 20the hypoglossal nerve- fibres from the medulla
- pure motor nerve that innervates all muscles of the tongue except for palatoglossus (important for poking out the tongue)
- when damaged the tip of the tongue deviates to the affected side. The tongue becomes wrinkled and flaccid
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- 2005 Flashcards on cranial nerves 2005, created by Soph B on 17/09/2019.
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