Cranial Nerves, Vison, Audition, and Equilibrium Flashcards
Cranial Nerve I
Name, Type, and Function
- Olfactory
- sensory
- conveys sense of smell
- Damage = distortion to smell and taste
Cranial Nerve II
Name, Type, and Function
- Optic
- Sensory
- vision
- Damage = various vision impairments
Cranial Nerve III
Name, Type, and Function
- Oculomotor
- Motor
- Moves 4/6 extraocular nerves
- Parasympathetic NS
- Accomodation of the lens
- Pupillary constriction
- eyeball convergence
- Damage = diplopia, strabismus (incoordination of eyes), ptosis (eyelid drooping) and mydriasis (pupil dilation), inability to open eye, copensatory head tilting
Cranial Nerve IV
Name, Type, and Function
- Trochlear
- Motor
- moves superior oblique extraocular muscle
- Damage = diplopia
- affected eye adducted and elevated
- eye cannot move downwards properly
Cranial Nerve V
Name, Type, and Function
- Trigeminal nerve (three parts)
- Sensory
- brings in sensory information from the face and jaw
- Motor
- moves the muscles of mastication (masseter)
- Damage = trigeminal neuralgia (pain), cluster headache, trigeminal zoster
Cranial Nerve VI
Name, Type, and Function
- Abducens nerve
- Motor
- moves the lateral rectus extraocular muscle
- Damage = diplopia
- eye is pulled towards the nose
Cranial Nerve VII
Name, Type, and Function
- Facial nerve
- Sensory
- taste from anterior 2/3 of tongue
- Motor
- moves all muscles of facial expression
- Parasympathetic NS
- stimulates salivation and lacrimal glands
- Damage = facial palsy, Bell’s palsy
- drooping of affected side of face
Cranial Nerve VIII
Name, Type, and Function
- Vestibulocochlear
- Sensory
- brings auditory (hearing) information from the cochlea
- Brings in angular acceleration (balance) info from semicircular canals
- Brings in static acceleration (balance) info from vestibule
- Damage = sensation of spinning, loss of hearing
Cranial Nerve IX
Name, Type, and Function
- Glossopharyngeal nerve
- Sensory
- taste in the posterior 1/3 of the tongue
- Motor
- stimulates skeletal muscle in pharynx ad larynx for swallowing
- Parasympathetic NS
- Brings in cardiovascular sensory info from carotid sinus
- [blood pressure (baroreceptors) and blood chemistry chemoreceptors)}
- Stimulates salivation of the parotid salivation gland
- Damage = absence of gag reflex, deviation of uvula
Cranial Nerve X
Name, Type, and Function
- Vagus Nerve
- Sensory
- brings in taste from the base of the tongue and oropharynx
- Motor
- stimulates skeletal muscles in the pharynx and larynx in swallowing
- Parasympathetic NS
- sensory and motor for most of the viscera; control stopes at the level of the colon
- Damage = increase BP, increase HR, difficulties in swallowing
Cranial Nerve XI
Name, Type, and Function
- Accessory
- Motor
- stimulates skeletal muscle in the pharynx and larynx for swallowing
- Stimulates the sternocleidomastoid muscle
- Stimulates the trapezius muscle
- Damage = ipsilateral weakness of the trapezius, inability to raise the scapula, weakness of sternocleidomastoid muscle
Cranial Nerve XII
Name, Type, and Function
- Hypoglossal
- Motor
- stimulates the tongue
- Damage = tongue deviates to the side of damage
Nerves that control eye movement
CN III - oculomotor -
CN IV - trochlear -
CN VI - abducens -
Nerves that control taste
- VII - facial - anterior 2/3
- IX - glossopharyngeal - posterior 1/3
- X - vagus - base/oropharynx
Nerves that control salivation
- VII - (facial) sublingual, submandibular
- IX - (Glossopharyngeal) parotid
Nerves that control swallowing
- involuntary phase
- IX - glossopharyngeal
- X - vagus
- XI - accesory
- voluntary phase
- XII - hypoglossal
Nerves that control the parasympathetic NS
- III - occularmotor - close vision
- VII - facial - salivation; lacrimal
- IX - glossopharyngeal - sensory in: CV pressure/chemistry salivation
- X - vagus - rest and digest
Exteroreceptors
- by which one perceives the outside world
- skin, mucus membranes, special senses
Interoreceptors
- by which one perceives pain, hunger, etc., and the movement of internal organs
- Proprioceptors in muscle spindles, golgi tendon organ, joint capsules, and inner ear
- Visceroceptors (in organs or passageways): baroreceptors, stretch receptors, chemoreceptors
The attributs of sensation are
- Modality
- Quality of the modality
- Quantity
- Localization of projection
Modality is
the type of sensory information, including exteroceptive, proprioceptive or visceroceptive
Quality of modality refers to
the exact kind and depth of modality
i.e. with touch it can be temperature, light touch, deep pressure, vibration.
Quality is carried to the brain on a specific tract called labeled line coding.
The sensation attribute of quantity is
the intensity of a threshold potential as coded by frequency of the action potentials; either by population coding or labeled line coding
The attribute of sensation, localization of projection is
- the stimulus affects a receptive field.
- Info from the receptive field is then carried to a specific region of the primary sensory area of the parietal lobe in the brain (post central gyrus) providing awareness of stimulation
What is the law of specific nerve energies
- All receptors will respond to a very strong stimulus
- regardless of type or strength of stimulaus to a given receptor, the receptor will always respond the same.
- eg: application of pressure to the eyeball will result in a visual sensation event of “seeing light”
The Law of adequate stimulus
aka optimal stimulus, unique stimulus to which a particular receptor responds and is most sensitive
eg: light is the most optimal stimulus for the retina