Cranial nerves Flashcards
the first cranial nerve arises from?
Telencephalon
the second cranial nerve arises from?
Diencephalon
The Third and Fourth cranial nerve arises from?
Mesencephalon
The Fifth through 12th cranial nerves arises from?
Rhombencephalon
the trochlear nerve is unique in that it arises from the?
anterior (basal) surface of the brain
all cranial nerves are part of?
the Peripheral nervous system
list the cranial nerves in order
Olfactory (I); Optic (II); Oculomotor(III); Trochlear(IV); Trigeminal (V); Abducens(VI); Facial (VII); Vestibulocochlear(VIII); Glossopharyngeal(IX); Vagus (X); Accessory (XI); Hypoglossal (XII)
Cranial nerves are composed of what kind of fibbers?
Heterogeneous nerves (motor sensory or a mix of both)
the olfactory nerve arises from? And passes Through?
Arises from the olfactory epithelium and passes through the cribriform plate of the ethmoid bone
Fibbers from the olfactory nerve synapse with?
Fibbers end in the olfactory bulb and synapse with interneurons and mitral nerve cells
the olfactory nerve is the only nerve whose fibbers do not pass through? And is the only nerve capable of?
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)
the optic nerve passes through the?
Optic canal
Rods and cones are absent on the?
Optic disk
The retina contains what two types of photoreceptors? What are they used for?
The retina contains two types of photoreceptors; rods and cones; Rods are for night vision; cones for daylight and colour
light passes through what before reaching the photoreceptors?
Light passes through all layers of the retina before reaching
the photoreceptors
what are the three retina neuronal cell layers?
Photoreceptor cell layer (rods and cones); Interneuron cell layer (horizontal bipolar and amacrine); Ganglionic cell lay
Axons from the retinal ganglion cells form the? They exit the retinal at the?
Optic nerve; Optic disk
information from the right visual field is processed in the? Information from the left visual field?
Right visual field -> Left visual cortex; Left visual field -> Right visual cortex
what are the four eye muscles (not smooth) innervated by the Oculomotor nerve?
Superior medial and inferior rectus and the inferior oblique
what are the two smooth eye muscles innervated by the Oculomotor nerve?
ciliary muscle (CM) and sphincter pupillae (SP)
What is the Path of the Oculomotor nerve?
originates from the midbrain; passes through the superior orbital fissure
describe the pupillary light reflex
When bright light enters one eye; the pupils of both eyes become smaller
the trochlear nerve passes through the? It innervates what muscle
Passes through the superior orbital fissure; Innervates the superior oblique muscle of the eye (is a motor nerve)
what it the trochlea?
the tendon of the superior oblique muscle passes through a cartilaginous sling; called trochlea
the trigeminal nerve is the? What are the three major branches?
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)
what is the path of the ophthalmic nerve? It carries what?
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)
what is the maxillary nerve path? What does it carry?
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)
what is the mandibular nerve path? What does it carry?
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
what is the path Abducens nerve? What does it innervate?
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
what is the path of the facial nerve; what does it carry?
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
what is the path of the Vestibulocochlear nerve; what does it innervate?
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
what is the path of the Glossopharyngeal nerve? What does the nerve carry?
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
what is the path of the Vagus nerve? What does the nerve carry?
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
what are the components of the Accessory nerve? What does the nerve innervate?
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)
what is the path of the Hypoglossal nerve? What does the nerve innervate?
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
