ON Flashcards
On is extension of what part of the brain
Diencephalon
Neuro retinal rim tissue
Optic disc
Contains the retinal ganglion cells that constitute the neurosensory retina coalescing at the ON
Optics disc
The absence of retinal nerve fiber cells
Optic cup
Common C/D ratios
0.2-0.4
Midget cells
Parvocellular pathway
What it is
Finer resolution
Midget cells project to the ___ and connect with ____
LGN
Connect w midget bipolar cells that connect with few, photoreceptors
80% (most) of retinal ganglion cells are
Midget cells (what it is pathway)
Parasol cells
Magnocellular pathway
Where it is
Motion detection
Need to communicate with many receptors for their function
Parasol cells because of the larger area of reference
What RGC are preferentially prone to glaucoma damage?
Parasol cells
30% of >1 million RGCs are reserved solely for
The central 8 degrees of the macula around the fovea
Papillomacular nerve fiber bundles
Include fovea & macula areas, straight horizontal
Arcuate nerve fibers
Located superior and inferior temporally in the retina coursing around the fovea delineated by the horizontal Raphe
Nasal nerve fibers
Radial course for the vast temporal fields of our peripheral vision
Glaucoma respects
Horizontal
Lamina cribosa is a threshold of fenestrations found
Posteriorly where RGC axons and astrocytes binder to carry into to CNS
Site of CRA and CRV entering the optics nerve
Lamina cribosa
Where does myelination begin in lamina cribosa
Posteriorly
Trans lamina cribrosa pressure
Difference on IOP and ICP
Norm is <5mmHg
SVP is only seen when
Trans laminar pressure is overall normal
True papilledema etiology stems from
Increased CSF
High ICP can be from retrobulbar increase in CSF or introrbital/cranial space lesion can result in
Swollen/elevated ONH
Papilledema
This portion of the optic nerve is surrounded by myelination at the micro level of the axons and meninges at the macro level of the nerve
Retro lamina intraorbital
