Nervous System V

Question 1

Describe the olfactory nerve

Answer 1

Special afferent
-sense of smell

• Axons of sensory receptors pass through the cribiform plate of the ethmoid bone
• Terminate in the olfactory bulbs
• Anosmia= loss of sense of smell

Question 2

Describe the optic nerve

Answer 2

Special afferent
-sense of vision

Axons of ganglion cells form the optic nerve

Optic nerve passes through the optic chiasm

Anopia = loss of sense of vision

Question 3

Where do abducens, trochlear and Oculomotor pass through?

Answer 3

The superior orbital fissure

Question 4

Describe the Oculomotor nerve (III)

Answer 4

General somatic afferent

• motor to extraocular muscles
• Superior rectus.
• legatos palpebrae superioris
• medial rectus
• inferior rectus
• inferior oblique

General visceral efferent

• Ciliary ganglion
• Parasympathetic to intrinsic smooth muscles of the eye
  
  • Ciliary muscle
    
    • accommodation
  • Sphincter pupillae of iris
    
    • constriction

Question 5

Describe trochlear(IV) nerve

Answer 5

General somatic efferent

• motor to extraocular muscle
  
  • superior oblique

Question 6

Describe the abducens(VI)

Answer 6

General somatic efferent

• motor to extraocular muscle
  
  • lateral rectus

Question 7

What are the actions of the Oculomotor nerve?

Answer 7

Look laterally and upward- superior rectus

Look laterally and downward- inferior rectus

• look medial- medial rectus
• look medically and upward-inferior oblique

Question 8

WHat is the function of the CNIV trochlear ?

Answer 8

Look medically and downward -superior oblique

Question 9

What are the functions of CN VI (abducens)?

Answer 9

Superior oblique-look medically and downward

Question 10

What is the. Function of the V1-ophthalmic branch of the trigeminal nerve ?

Answer 10

• superior orbital fissure
• general somatic afferent
  
  • sensory to skin over eye, cornea, lacrimal gland and superior nasal cavity

Question 11

What is the function of the maxillary branch (V2) of the trigeminal branch?

Answer 11

Foramen rotundum

• general somatic afferent
  
  • sensory to skin of lower eyelid, upper lid, lower nasal cavity, palate, upper teeth

Question 12

What is the function of the mandibular branch(V3)?

Answer 12

Foramen ovale
General somatic afferent
-sensory to anterior 2/3 of tongue, mandible, lower teeth, cheek, chin

Branchial efferent

• Motor to muscles of mastication
  
  • medial & lateral pterygoid
  • temporalis
  • masseter

Question 13

What is the function of the facial nerve(VII)?

Answer 13

Sensory sensory and motor

Special afferent
-sense of taste to anterior 2/3 tongue

General visceral efferent

• parasympathetic to lacrimal gland
  
  • Pterygopalantine ganglia
• Parasympathetic to submandibular and sublingual salivary glands
  
  • submandibular ganglia
• exits cranial cavity through internal acoustic meatus
• exits the skull through stylomastoid foramen

Question 14

What are the functions of the vestibulocochlear nerve(VIII)?

Answer 14

Special afferent

• vestibular branch
  - sense of equilibrium
• Cochlear branch
  • sense of hearing

Exits cranial cavity through the internal acoustic meatus

Question 15

What is the function of the glossopharyngeal nerve(IX) ?

Answer 15

Special afferent-special taste to posterior 1/3 of the tongue

General somatic afferent- posterior 1/3 tongue, oropharynx

General visceral &afferent- carotid sinus & body

Branchial efferent- motor to stylopharyngeas muscle

General visceral efferent-parasympathetic to parotid salivary gland -optic ganglia

Exits the cranial cavity through the jugular foramen

Question 16

What is the function of the vagus nerve(X)?

Answer 16

-General somatic afferent-laryngopharynx afferent

• General visceral afferent
  
  • Chemoreceptors of aortic afferent
  • Baroreceptors of aortic arch
• Special afferent
  
  • Sense of taste to epiglottis & pharynx
• General visceral efferent
  
  • Parasympathetic to pharynx, larynx, thoracic viscera, abdominal viscera of foregut & midgut
• Branchial efferent
  
  • Motor to palatoglossus, muscles of soft palate, pharynx & larynx

-Exits the cranial cavity through the jugular foramen

Question 17

What is the function of the accessory (XI) nerve?

Answer 17

• General somatic efferent
  
  • Motor to sternocleidomastoid & trapezius
• Enters the cranial cavity through the foramen magnum
• Exits through the jugular foramen

Question 18

What is the function of the hypoglossal nerve (XII)?

Answer 18

General somatic efferent
-motor to all intrinsic & most extrinsic muscles of the tongue

-Exits cranial cavity through the hypoglossal cranial

Question 19

What are the cranial nerve reflexes?

Answer 19

Corneal(blink) reflex

• Afferent
  
  • trigeminal (V1)
• efferent
  
  • facial(VII)

Gag reflex

• afferent(glossopharangeal)(IX)
• efferent vagus (X)

Pupillary reflex

• Afferent- optic(II)
• efferent- oculomotor (III)