01/21 Cranial Nerves Flashcards
(26 cards)
What are the sensory-only cranial nerves?
CN I - olfactory
CN II - optic
CN VIII - vestibulocochlear/acoustovestibular
What are the motor-only cranial nerves?
CN IV - abducens
CN VI - trochlear
CN XI - accessory spinal
CN XI - hypoglossal
What are the sensory/motor cranial nerves?
CN III - oculomotor CN V - trigeminal CN VII - facial CN IX - glossopharyngeal CN X - vagus
What are the functions of the oculomotor nerve?
Motor innervation to four eyeball muscles and levator palpebrae superioris
Parasympathetic innervation to the ciliary ganglion - contraction of the pupil
What are two prominent clinical findings when a patient has a damaged oculomotor nerve?
Fixed and dilated pupil
Ptosis of the upper eyelid
What are the functions of the trigeminal nerve?
Sensory innervation from the face, cornea, mouth, nose, and temporomandibular joint
Motor innervation to the muscles of mastication
What are the functions of the facial nerve?
Sensory innervation from the anterior 2/3 of the tongue
Motor innervation to the muscles of facial expression
Parasympathetic innervation to sublingual, submandibular, and lacrimal glands
What are the resulting symptoms of damage to the facial nerve?
Facial droop
Dry eyes
Dry mouth
What are the functions of the glossopharyngeal nerve?
Sensory innervation from the posterior 1/3 of the tongue, auditory tube, and pharynx
Parasympathetic innervation to the parotid gland
What are the functions of the vagus nerve?
Sensory innervation from the larynx and pharynx
Motor innervation to the larynx and pharynx
Parasympathetic innervation to organs of the chest and abdomen
What are the functions of the outer and middle ear?
To collect and amplify sound waves
What is the function of the hearing portion of the inner ear? What are its parts?
Transmits sound waves into mechanical movements and nerve impulses
Cochlea and hair cells
Trace the path of the vestibulocochlear nerve to the auditory cortex
1) Vestibulocochlear nerve
2) Dorsal and ventral cochlear nuclei (in the medulla)
3) Inferior colliculus via the lateral lemniscus
4) Medial geniculate nucleus (in the thalamus)
5) Primary auditory cortex - superior temporal lobe (Brodmann areas 41 and 42)
Axons from which visual field cross to the other side at the optic chiasm?
Temporal visual field
Trace the path of the optic nerve from the eye to the primary visual cortex
1) Optic nerve
2) Optic chiasm
3) Optic tract
4) Lateral geniculate nucleus
5) Optic radiations
6) Primary visual cortex - calcarine fissure in occipital lobe (Brodmann area 17)
What is the result of a lesion in one eye or one optic nerve?
Right or left anopsia (single-eye blindness)
What is the result of a lesion to the optic chiasm?
Bitemporal hemianopsia (tunnel vision)
What is the result of an injury to the optic tract, optic radiations, or optic visual cortex?
Homonymous hemianopsia (blindness in either the right or left visual field)
Trace the path of the olfactory nerve starting from the sensory receptors in the nasal mucosa
1) Bipolar receptor neurons in nasal mucosa
2) Impulses sent via the olfactory bulb and tract
4) Anterior perforated substance
* Also connections with the entorhinal cortex, amygdala, hippocampus, fornix, and mammillary bodies
What system is intimately related with the olfactory system?
Limbic system
What functions are regulated by the hypothalamus?
Sleep Body temperature Water balance Blood pressure Hunger Pituitary hormone secretion Sympathetic and parasympathetic balance
What are the functions of the descending reticular system?
Projects to autonomic nervous system (sympathetic and parasympathetic)
Relays extrapyramidal output to the voluntary muscles via the pontine tegmentum
What are the functions of the ascending reticular activating system?
Provides input from all sensory organs to the thalamus and cortex
Important for arousal from sleep by stimuli
Which cranial nerve nuclei are located in the midbrain?
Oculomotor (III)
Trochlear (IV)
