speech and hearing related cranial nerves (functions)

• CN V - Trigeminal Nerve

• Functions

  • Sensation of the face, teeth, gums, and anterior 2/3 of the tongue

  • Flattenting and tensing the soft palate and for opening the eustachian tube.

  • Assist in the upward and anterior movement of the larynx

• CN VII - Facial Nerve

• Functions

  • Responsible for all movements of facial expressions like eyes, nose, mouth, and external auditory canal which allow:

    • Wrinkle your forehead

    • Close your eyes tightly

    • Close your mouth

    • Pull back the corners of your mouth and tense your cheeks

    • Pull down the corners of your mouth and tense your anterior neck muscles

  • Assists in lifting the larynx up and back through the belly of digastric muscle

  • Provides motor innervation to the sublingual and sub maxillary salivary glands

  • Stapedius muscle in the middle ear, which dampens excessive movement of the ossicles in the presence of loud sounds

• CN VIII - Acoustic-Vestibular

• Functions

  • Takes afferent information form the inner ear to the central nervous system

  • Responsible for sound sensitivity

  • Innervates the utricle and saccule of the inner ear, which are sensitive to static changes in equilibrium

  • Innervated the semicircular canals, and controls sensitivity to dynamic changes in equilibrium.

• CN IX - Glossopharyngeal Nerve

• Functions

  • Dilates the pharynx laterally contributing to the elevation of the pharynx and larynx. Thus helps clear the pharynx and larynx for swallowing

  • Parotid gland's production of saliva 

  • Sensory fibers cry taste information from the posterior third of the tongue

  • Mediated the sensory portion of the pharyngeal gag

• CN X - Vagus Nerve

• Function

  • Efferent nerve for pharyngeal constrictors and is afferent to the middle and inferior portions of the pharynx

  • Mediates sensation of the epiglottis

  • Innervated muscles of the pharynx

• CN XI - Spinal Accessory Nerve

• Function

  • Motor innervation to the sternocleidomastoid muscles to help turn, tilt, and thrust the head forward or raise the sternum and clavicle if the head is in a fixed position.

  • Innervated the trapezius muscle, responsible for shrugging the shoulders

• CN XII - Hypoglossal Nerve

• Function

  • Innervates the muscles responsible for tongue movement

  • 4 intrinsic muscle of the tongue control - shortening, concaving, narrowing, elongating, and flattening

  • Extrinsic muscles of the tongue control - protrusion (genioglossus) draw the tongue upward and backward (styloglossus), and retract and depress the tongue (hyoglossus) 

how many cranial nerves related to speech an hearing

7/12