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The Cranial Nerves are nerves that originate from the brain stem.

Are very specialized and important set of nerves.

There are 12 overall and they control a variety of functions both motor or sensory

Motor is the movement of a muscle [Efferent]

Sensory is the sight, touch or smells of the senses that are transmitted to the brain  [Afferent]

Many cranial nerves are either Motor  [Efferent] or Sensory [Afferent] but a some are both

Cranial Nerves:

I  Olfactory or smell  [Afferent]

• Transmits sense of smell

II  Optic or vision [Afferent]

• Transmits visual information from eye to brain

III  Oculomotor or movement of eyeball  [Efferent]

• Innervates levator palprebrae of the eye
• Innervates superior rectus of the eye
• Innervates medial rectus of the eye
• Innervates inferior rectus of the eye
• Innervates inferior oblique of the eye
• Affects the majority of eye movement
• The exceptions are with Cranial nerves IV and VI

IV  Trochlear or muscles of eyeball  [Efferent]

• Innervates superior oblique muscle of the eye
• Allows for movements of eye including: lateral, depresses, and intorts

V  Trigeminal   [Afferent]  and  [Efferent]

• V1 – opthalmic [Afferent]
• V2 – maxillary  [Afferent]
• V3 – mandibular  [Afferent] and [Efferent]
• Receives sensation from the face.
• Innervates facial muscles for mastication [chewing]

VI   Abducens or muscles of eyeball  [Efferent]

• Innervates the lateral rectus of the eye
• Affects the abduction of the eye

VII   Facial   [Afferent] and  [Efferent]

• Motor innervation to the muscles of the face
• Allows for facial expressions
• Receives senses of taste from the anterior 2/3 of the tongue
• Affects secretion of the salivary glands [except parotid]

VIII   Vestibulocochlear  [Afferent]

• Senses Gravity
• Senses Sound
• Senses Rotation
• Essential for balance and movement

IX   Glossopharyngeal  [Afferent]  and  [Efferent]

• Receives taste from the posterior 1/3 of the tongue
• Affects secretion of the Parotid gland
• Affects some sensation of the Tonsils

X   Vagus [Afferent]  and  [Efferent]

• Supplies motor innervation to most laryngeal and all pharyngeal muscles
  
• Controls muscles for voice
• Helps control soft palate

XI   Accessory or spinal   [Efferent]

• Controls sternocleidomastoid
  
• Controls trapezius muscles
• Helps with shrugging shoulders

XII   Hypoglossal or tongue  [Efferent]

• Provides motor innervation to the muscles of the tongue
• Important for Speech
• Important for Swallowing

Below is a Video of the Cranial Nerve Examination