Cranial Nerves Flashcards
Whats the similarity of spinal nerves? Whereas cranial nerves….
They all do the same job, jus in different locations! Whereas cranial nerves have very individual, specialised functions
The cranial nerves all come off the….
Brainstem!
Whats the saying to describe if the cranial nerve is Sensory, motor or both?
Where do the cranial nerves originate from in the brain??
1: Allocortex/limbus
2-3: Midbrain
4-6: Pons
7-12: medulla
Ordered from the front of the brain to the back.
Whats special about the accessory nerve #11
It reality should be labelled as a spinal nerve, is far more similar similar in function, but due to location it’s a CN
What is the housing ‘powerhouse’ of the cranial nerves and how does this affect it structurally
The Pons, and this causes it to be signifcantly enlarged in order to carry all the cranial nuclei
What is the reason for having such a large area within the Midbrain crus cerebri, for the corticobulber (facial) tract?
Because pretty much all of these nerves have info coming both too and from the face, so most of the info coming through this tract comes in/out in this region, and goes no further (why the spinal cord is so much skinnier)
What is Cranial Nerve 1?
Olfactory Nerve: fibres come down from olfactory bulb/tract to the nasal region, to the cribiform plate of ethmoid surrounded by mucous membrane. So if you put your finger up your nose you should be mm away from it
What is special about each Olfacotry nerve fibre ?
Each fibre detects a specific smell, so overall they detect everything we smell!
We get regenration of nerve cells in the olfactory bulb and the fibres coming from the bulb!
What is unique about the Olfactory Nerve?
- Only nerve to originate from the Allocortex.
- Only cranial nerve to not have much input from the thalamus
- The nerve fibres are the only nerves to be exposed to the outside environment via the Cribiform plate
Where’s the first place patients develop Parkinson’s and Alhziemers, and what does this mean they lose first?
The Olfactory Bulb, therefore patients first symptoms will be a loss of smell!
Why is the Olfactory bulb so important to our fight or flight response?
Because it feeds into the Limbic System (involved in fight/flight response) and is the only input into the Limbic system. You need this quick response, eg; you smell somthing burning → fight/flight response is engaged!
Cranial Nerve #2 is?
The Optic Nerve.
Carries info from the Retina → Lateral geniculate nucleus of the thalamus → fibres then project back via optic radiations → Visual Cortex.
There are areas of the cortex that deal solely with info, and others that process the info
What are the cranial nerves 3, 4 and 6 and how do the work together?
3: Occulomotor nucleus
4: Trochlear Nuclei
6: Abducer Nucleus
These all have a very similar function, to ensure smooth movement to follow/tract objects. These nerves each control a specific muscle of the eye to contract
LR 6, SO 4, 3
What eye muscles does the Occulomotor nerve control and what movement does this cause.
Controls the superior, medial and inferior rectus muscles to move the eye up, down and medially.
Also controls the inferior oblique muscle that pulls the eye up and medially
What eye muscle does the Troclhear nerve #4 control and what effect does this have?
Acts on the superior oblique to act as a ‘pulley’ to move your eyes inferiorally and medially.
Nerves go into very specific ______, which are mostly located in the ________.
Nerves go into very specific foramen, which are mostly located in the Sphenoid bone, between the middle and anterior fossa.
V1 Trigeminal Nerve covers?
Takes sensory info from Opthalamic Division
V2 Trigeminal Nerve infor
Takes info from the Maxillary division
Complete the summary diagram of the cranial Nerves
Sensory or motor
Function
Foramen
