cranial nerves 2 Flashcards
1
Q
what is the name of cranial nerve 2 and what is its special sensory
A
- optic nerve
- eyes
2
Q
what is the origin and destination of optic nerve
A
- origin - retina of eye
- destination - optic chiasm
3
Q
what is the route of optic nerve
A
- optic nerve exits the orbit via optic canals
- soon after reunite forming optic chiasm
- nasal retinal axons cross on opposite sides
- temporal retinal axon remains on same side
- axons divide again and continue as optic tracts
- terminating in lateral geniculate nucleus
- post synaptic fibres from lateral geniculate synapse in visual cortex of occipital lobe of brain
4
Q
what does damage to optic nerve before the chiasm cause
A
- blindess in eye
5
Q
what does damage to chiasm cause
A
- loss of temporal fields
6
Q
what does damage to optic tracts cause
A
- complex visual losses
7
Q
what is the clinical test
A
- shellen chart [measures visual acuity]
