Week 6: Cranial Nerves Flashcards
What are the “special sense” nerves?
- Cranial nerve 1 = Olfactory nerve (I)
- Cranial nerve 2 = Optic nerve (II)
- Cranial nerve 8 = Vestibular nerve (VIII)
What are the Somatic motor nerves in the eye?
- Cranial nerve 3 = Oculomotor nerve (III)
- Cranial nerve 4 = Trochlear nerve (IV)
- Cranial nerve 6 = Abducens nerve (VI)
What are the somatic motor nerves of the tongue?
- Cranial nerve 12 = hypoglossal nerve
- speech
What are the rest of the body nerves?
- Cranial nerve 9 = Glossopharyngeal nerve (IX) , swallowing
- Cranial nerve 10 = Vagus nerve (X) , heartbeat/digestion/metabolism
- Cranial nerve 11 = Spinal nerve (XI)
Face and jaws nerves?
- Cranial nerve 7 = Facial nerve (VII) (smile, close eyes forcefully)
- Cranial nerve 5 = Trigeminal (V) (sensory and jaw)
What are cranial nerves?
Nerves that come from the brainstem in brain and pass through the skull to destination origin that they’re concerned with, relate to the foramen of the skull, 12 in total
What are the somatic motor nerves and their target muscle (that they’re attached to)?
Cranial nerve 4 - trochlear nerve - superior oblique (exit is the superior orbital fissure / sphenoid, keyhole in skull cavity)
Cranial nerve 6 - Abducens nerve - Lateral rectus
Cranial nerve 3 - superior, medial and inferior rectus, inferior oblique, Levator palpebrae superioris
Parasympathetic nerve blood supply which controls pupil and accommodation which controls pupillary muscle (sympathetic system will make pupil dilated so can let in more light and see clearly / parasympathetic nerve system makes ciliary body and pupil contract so can focus on small details)
What is the olfactory bulb?
N. Of cells underneath the frontal cortex of the brain which pick up smells coming though sinuses so thats the smell area and one on each side of the head and they’re going to help you with smell
What eye does the right oculomotor nerve from the brain?
The left eye
Look at picture : View of cranial nerves as they emerge from brainstem
Idk
Where does the 3rd cranial nerve start and go to? (And parasympathetic motor fibres)
- ocularmotor nerve
- starts in the midbrain and inside nucleus is command centre for OM nerve
- When nerve comes out of brainstem and gets to superior orbital fissure, nerve splits in 2 branches; Inferior division & Superior division
- superior division goes up to eyelid and superior rectus
- Inferior division goes towards medial rectus and down towards inferior rectus and inferior oblique
- Parasympathetic motor fibres which are going towards the ciliary body and head towards the pupil
Where do all the signals from the 3rd cranial nerve start?
Oculomotor nucleus where signals and command start, cushioned by neural tissue. However if there was a bleed or tumour in this region, px will also present with some external signs that indicate their is something wrong in the brainstem.
- might see this in px who has cancer or tumour, they get tremors in one side of body and will also have problems moving their eyes in all directions
- might have hemiplegia which is one half of the body is paralysed because red nucleus is responsible for sending signals out to body for movement so if damages, will get combo of eye that cant move in some directions plus might be unsteady on their feet and tremor with hands e.c.t.
What is the circle of Willis?
- round structure, key point where lots of blood coming up and all the vessels are all going to different parts
- post cerebral artery + carotid artery + basilar artery
Why is pituitary gland important?
Maintaining hormonal control, problems here can affect vision in different ways
What is the PCA and role?
Posterior communicating artery, allows blood to transfer from the front of the Willis to the back the Willis
Prone to aneurisms which is when you get blooming or swelling in this area, it starts to compress on the third cranial nerve (Oculomotor nerve) then all signals passing through eye will be blocked and eye will stop moving properly.
-these px will present with a pupil that is dilated, vision might be okay but cant move eye in many directions, which is emergency cause aneurism, and if it bursts then person will die
Why is it an emergency if you see a px with eye that cant move up/down/left/right and dilated pupil?
They have an aneurism and if it bursts they will die