Cranial nerves

Question 1

the first cranial nerve arises from?

Answer 1

Telencephalon

Question 2

the second cranial nerve arises from?

Answer 2

Diencephalon

Question 3

The Third and Fourth cranial nerve arises from?

Answer 3

Mesencephalon

Question 4

The Fifth through 12th cranial nerves arises from?

Answer 4

Rhombencephalon

Question 5

the trochlear nerve is unique in that it arises from the?

Answer 5

anterior (basal) surface of the brain

Question 6

all cranial nerves are part of?

Answer 6

the Peripheral nervous system

Question 7

list the cranial nerves in order

Answer 7

Olfactory (I); Optic (II); Oculomotor(III); Trochlear(IV); Trigeminal (V); Abducens(VI); Facial (VII); Vestibulocochlear(VIII); Glossopharyngeal(IX); Vagus (X); Accessory (XI); Hypoglossal (XII)

Question 8

Cranial nerves are composed of what kind of fibbers?

Answer 8

Heterogeneous nerves (motor sensory or a mix of both)

Question 9

the olfactory nerve arises from? And passes Through?

Answer 9

Arises from the olfactory epithelium and passes through the cribriform plate of the ethmoid bone

Question 10

Fibbers from the olfactory nerve synapse with?

Answer 10

Fibbers end in the olfactory bulb and synapse with interneurons and mitral nerve cells

Question 11

the olfactory nerve is the only nerve whose fibbers do not pass through? And is the only nerve capable of?

Answer 11

Is the only nerve whose fibbers do not pass through the thalamus (an exception); is the only nerve (olfactory nerve) capable of regeneration (an exception)

Question 12

the optic nerve passes through the?

Answer 12

Optic canal

Question 13

Rods and cones are absent on the?

Answer 13

Optic disk

Question 14

The retina contains what two types of photoreceptors? What are they used for?

Answer 14

The retina contains two types of photoreceptors; rods and cones; Rods are for night vision; cones for daylight and colour

Question 15

light passes through what before reaching the photoreceptors?

Answer 15

Light passes through all layers of the retina before reaching
the photoreceptors

Question 16

what are the three retina neuronal cell layers?

Answer 16

Photoreceptor cell layer (rods and cones); Interneuron cell layer (horizontal bipolar and amacrine); Ganglionic cell lay

Question 17

Axons from the retinal ganglion cells form the? They exit the retinal at the?

Answer 17

Optic nerve; Optic disk

Question 18

information from the right visual field is processed in the? Information from the left visual field?

Answer 18

Right visual field -> Left visual cortex; Left visual field -> Right visual cortex

Question 19

what are the four eye muscles (not smooth) innervated by the Oculomotor nerve?

Answer 19

Superior medial and inferior rectus and the inferior oblique

Question 20

what are the two smooth eye muscles innervated by the Oculomotor nerve?

Answer 20

ciliary muscle (CM) and sphincter pupillae (SP)

Question 21

What is the Path of the Oculomotor nerve?

Answer 21

originates from the midbrain; passes through the superior orbital fissure

Question 22

describe the pupillary light reflex

Answer 22

When bright light enters one eye; the pupils of both eyes become smaller

Question 23

the trochlear nerve passes through the? It innervates what muscle

Answer 23

Passes through the superior orbital fissure; Innervates the superior oblique muscle of the eye (is a motor nerve)

Question 24

what it the trochlea?

Answer 24

the tendon of the superior oblique muscle passes through a cartilaginous sling; called trochlea

Question 25

the trigeminal nerve is the? What are the three major branches?

Answer 25

The trigeminal nerve is the largest of all cranial nerves; It has three major branches (trigeminal = three twins) which can be identified at the trigeminal ganglion: the ophthalmic nerve (V1); the maxillary nerve (V2) and the mandibular nerve (V3)

Question 26

what is the path of the ophthalmic nerve? It carries what?

Answer 26

passes through superior orbital fissure; carries only sensory fibres that supply: (skin of the forehead eyelids eyebrow and nose; the eye (e.g. Pain sensation of the cornea &
conjunctiva); mucous membrane of the upper nasal cavity)

Question 27

what is the maxillary nerve path? What does it carry?

Answer 27

passes through foramen rotundum; carries only sensory fibres that supply: skin of the mid-face; all upper teeth (maxillary teeth) and the maxillary bone [hence the name maxillary nerve]; mucous membrane of the lower nasal cavity; paranasal air sinuses; palate (hard & soft)

Question 28

what is the mandibular nerve path? What does it carry?

Answer 28

passes through oval foramen; mixed nerve (sensory & motor fibres) that supply: Sensory: skin of the lower face; all lower teeth (teeth of the mandible); mandibular bone; anterior 2/3 of the tongue (not taste!!!); Motor: muscles of mastication (e.g. masseter; temporalis; pterygoids); middle ear muscles (tensor tympani); muscles of the oral diaphragm

Question 29

what is the path Abducens nerve? What does it innervate?

Answer 29

originates from the anterior border of the pons and medulla oblongata; Passes through the superior orbital fissure; Innervates the lateral rectus muscle of the eye (is a motor nerve) which abducts the eye

Question 30

what is the path of the facial nerve; what does it carry?

Answer 30

travels through internal acoustic meatus and emerges through stylomastoid foramen; mixed nerve:

• motor component: for muscles of facial expression
• Special sensory component: for taste anterior 2/3 of the tongue
• Parasympathetic component: tear gland; salivary glands (submandibular and lingual); & nasal glands

Question 31

what is the path of the Vestibulocochlear nerve; what does it innervate?

Answer 31

Fibbers arise from the vestibular apparatus (balance) and cochlea (hearing) of the inner ear; travel through the internal acoustic meatus; and enter the brainstem at the pons-medulla border; Vestibular nerve carries information concerned with the position of the head in relation to movement
of the head and gravity; cochlear nerve is concerned with hearing

Question 32

what is the path of the Glossopharyngeal nerve? What does the nerve carry?

Answer 32

Fibbers emerge from the medulla and exit via the jugular foramen; Is a mixed nerve:

• Special sensory component: taste sensation from dorsal 1/3 of the tongue
• General sensory component: pharynx and dorsal 1/3 of the tongue
• Motor component: some muscles of the pharynx
• Parasympathetic component: parotid salivary gland

Question 33

what is the path of the Vagus nerve? What does the nerve carry?

Answer 33

Fibbers emerge from the medulla and exit via the jugular foramen; Is a mixed nerve:
- Special sensory component: taste sensation
- General sensory component: larynx; external ear
- Motor component: some muscles of the pharynx as well as
oesophagus; and all muscles of the larynx
- Parasympathetic component: all organs of the neck; thorax;
upper abdomen; and most parts of the intestine

Question 34

what are the components of the Accessory nerve? What does the nerve innervate?

Answer 34

is a pure motor nerve with two structural parts:
- Cranial part originates from the brain stem and merges with Vagus nerve (hence accessory nerve)
- Spinal part emerges from spinal cord; enters the skull via foramen magnum; merges with its cranial counterpart; and both leave the skull through the jugular foramen
It innervates two muscles of the neck (trapezius and sternocleidomastoid)

Question 35

what is the path of the Hypoglossal nerve? What does the nerve innervate?

Answer 35

Fibbers arise from the medulla and exit the skull via the hypoglossal canal; The only cranial nerve to exist most anteriorly from the medulla (between pyramids and olives); Is a motor nerve that innervates all muscles of the tongue