nervous system

• nervous system - the center of mental activity including thought, learning, and memory
• cranial nerves - 12-paired nerves that originate in the brain and the brainstem (carry impulses/signals)
• I (olfactory) - sense of smell
• II (optic) - sense of sight
• III (oculomotor) - controls eye movement, pupil size, and eye position
• IV (trochlear) - controls one muscle that turns eyes downward and outward
• V (trigeminal) - sensory nerve to face; motor control over chewing muscles
• VI (abducens) - moves lateral rectus muscle which allows us to look sideways
• VII (facial) - controls face movements and expressions
• VIII (acoustic/vestibulocochlear) - responsible for hearing and balance
• IX (glossopharyngeal) - swallowing, taste, and sensation of the mouth and pharynx
• X (vagus) - parasympathetic nerve responsible for heart rate and digestion
• XI (accessory) - provides motor function to two muscles essential to neck and shoulder movement
• XII (hypoglossal) - responsible for tongue movement
• sensation - the perception of stimuli by the sensory receptors in the body
• main senses:

  sight (vision)

  hearing (audition)

  smell (olfaction)

  taste (gustation)

  touch (tactile perception)
• 12-paired cranial nerves:

  I olfactory

  II optic

  III oculomotor

  IV trochlear

  V trigeminal

  VI abducens

  VII facial

  VIII acoustic (vestibulocochlear)

  IX glossopharyngeal

  X vagus

  XI accessory

  XII hypoglossal
• smell: I olfactory

  sight: II optic

  eye movement and pupil reflex: III oculomotor

  eye movement: IV trochlear

  face sensation and chewing: V trigeminal

  eye movement: VI abducens

  face movement and taste: VII facial

  hearing and balance: VIII acoustic (vestibulocochlear)

  throat sensation, taste, and swallowing: IX glossopharyngeal

  heart rate, digestion: X vagus

  neck movement: XI accessory

  tongue movement: XII hypoglossal