Cranial nerves Flashcards
(14 cards)
Cranial nerves
12 bilaterally paired nerves, which carry both afferent and efferent fibres between the brain and peripheral structures, principally of the head and neck. CN I and II attach directly to the forebrain, while CN III-XII connect to cranial nerve nuclei within the brainstem.
Cranial nerve nuclei
Groups of cell bodies of 10 of the cranial nerves, located within the brainstem.
CN I
Olfactory nerve; responsible for olfaction (sense of smell)
-special sensory afferent neurones innervate the olfactory epithelium in the nasal cavity
CN II
Optic nerve; responsible for vision and the pupillary light reflex
-special sensory afferent neurones innervate the retina
CN III
Oculomotor nerve; responsible for movement of the eyeball, elevation of the upper eyelid. pupillary constriction and lens accomodation
- motor neurones innervate 4 of the 6 extraocular muscles (sup., med., inf. rectus, inf. oblique) and the levator palpebrae superioris
- parasympathetic neurones innervate the sphincter pupillae and ciliary muscle
CN IV
Trochlear nerve; responsible for movement of the eyeball
-motor neurones innervate 1 of the extraocular muscles (sup. oblique)
CN V
Trigeminal nerve; composed of opthalmic, maxillary and mandibular nerves, responsible for general sensation, mastication, dampening loud noises, and events during swallowing
- sensory neurones innervate the face, scalp, cornea, nasal and oral cavities, cranial dura mater
- motor neurones innervate the muscles of mastication, tensor tympani, and tensor veli palitini
CN VI
Abducens nerve; responsible for movement of the eyeball
-motor neurones innervate 1 of the extraocular muscles (lat. rectus)
CN VII
Facial nerve; responsible for facial movement, swallowing, jaw movement, dampening loud noises, taste, lacrimation, mucous secretion and salivation
- motor neurones innervate the muscles of facial expression and stapedius muscle
- special sensory afferent neurones innervate the anterior 2/3 of the tongue
- parasympathetic neurones innervate the lacrimal glands, mucous glands of the nose, palate and sinuses, sublingual and submandibular salivary glands
CN VIII
Vestibulocochlear nerve; responsible for hearing, equilibration (balance) and vestibular sensation (position and movement of the head)
-special sensory afferent neurones innervate the vestibular apparatus and cochlea
CN IX
Glossopharyngeal nerve; responsible for general sensation, taste, baroreception, chemoreception, swallowing and salivation
- sensory neurones innervate the pharynx, posterior 1/3 of the tongue, Eustachian tube and middle ear
- special sensory afferent neurones innervate the posterior 1/3 of the tongue, carotid sinus and carotid body
- motor neurones innervate the stylopharyngeus muscle
- parasympathetic neurones innervate the parotid salivary gland
CN X
Vagus nerve; responsible for general sensation, visceral sensation, chemoreception, baroreception, taste, speech, swallowing, innervation of cardiac muscle, innervation of smooth muscle and glands of cardiovascular ssystem, respiratory and GI tracts
- sensory neurones innervate the pharynx, larynx, trachea, oesophagus and external ear
- special sensory afferent neurones innervate the thoracic and abdominal viscera, aortic bodies, aortic arch and epiglottis
- motor neurones innervate the soft palate, pharynx, larynx and upper oesophagus
- parasympathetic neurones innervate the thoracic and abdominal viscera
CN XI
Accessory nerve; responsible for the movement of the head and shoulder
-motor neurones innervate the sternomastoid and trapezius muscles
CN XII
Hypoglossal nerve; responsible for the movement of the tongue, speech and swallowing
-motor neurones innervate the extrinsic and intrinsic muscles of the tongue
