Week 8 Cranial nerves Flashcards
How many cranial nerves are there?
12 pairs
How are the cranial nerves named?
By roman numerals in reference to their attachment to the brain in an anterior to posterior direction
They are named as cranial nerves as they emerge through the foramina or fissures in the cranium/ skull
What are the cranial nerves covered in?
Sheaths formed by the cranial meninges
Where do most of the cranial nerves arise?
Mainly off the brain stem
What portion of the brain stem do the cranial nerves arise?
The medulla, pons and midbrain
What is the brain stem?
The connecting link between the remainder of the brain and the spinal cord
What are the main functional components of cranial nerves?
motor: Somatic motor (efferent) Visceral motor (efferent) Sensory: General sensory (touch, pain and temperature) Visceral sensory (afferent) Special sensory
What do the cranial nerves innervate?
Structures in the head and neck and visceral organs of the trunk
What kind of nerve is the olfactory nerve and where does it originate and end?
Cranial nerve 1
Special sensory
Begins at the mucosa of the nasal cavity and ends at the olfactory bulb in the cerebral cortex
What is the olfactory nerve composed of and what do they respond to?
Both neurons and receptors
Respond to volatile chemicals
Where does the olfactory nerve run?
Through the foramina of the cribirform plate
pierce dura and arachnoid mata
enter olfactory bulb
then becomes the olfactory tract
What is the function of the olfactory nerve?
Sense of smell
Arousal of emotions
induce visceral responses through ANS
What kind of nerve is the optic nerve?
Cranial nerve 2
Special sensory
What is the optic nerves claim to fame?
The largest (thickest) cranial nerve
Where is visual information relayed to?
visual coriticies of the occipital lobes
What nerve fibres does the occulomotor nerve recieve?
Both parasympathetic and sympathetic fibres.
Where does the occulomotor nerve begin and end?
Cranial nerve 3
originates in the midbrain
it then leaves the cranial cavity
then enters the orbit through the superior orbital fissure
What are the functions of the occulomotor nerve?
Provides motor function to 4 extraocular muscles
motor supply to the upper eyelid
Supplies parasympathetics to the sphincter of the pupil and cillary muscle of the lens
Where does the trochlea nerve originate?
Cranial nerve 4
The midbrain, it emerges from its dorsally from the brainstem
What is the trochlea nerves claim to fame?
Longest intracranial course
What is the function of the trochlea nerve?
somatic motor nerve to one of the extraocular muscles and proprioception