Flashcards in Midterm 1 Deck (282)
Visual pathway order
retina, ON. chiasm, tract, lgn, radiations, striate cortex
- photon strikes photopigment
-photopigment splits- chemical rxn produce message
(between PR and Gang)
axons (optic nerve) --> optic chiasm --> optic tract
axon --> optic radiations
which part of the ON is the longest?
what part of the sphenoid does the ON go through?
list the parts of the ON from shortest to longer
intraocular < intracanalicular < intracranial < intraorbitll
how many fibers does the ON have
what is the horizontal diameter of ONH
1.5 mm (1500um)
what is the prelaminar part of the intraocular nerve
fascicles: sheats of astrocytes bundle ~1000 fibers per fascicle
what is the laminar part of the intraocular nerve
within the lamina cribosa
pathway of ganglion cells
ganglion cells from retina to LGN then become optic radiations
what is the lamina cribosa
network of sclera fibers where the ON exits the eye
- if IOP goes up --> damage to the perforated nerve fibers that are in the sclera
intraorbital portion of the ON diameter
intraorbital portion of the ON postlaminar
Fascicles acquire a connective tissue sheath and become myelinated by oligodendrocytes
-surrounded by EOMs
what is longer: globe or intraorbital
intraorbital is loner than the apex-apex measurement of the globe
what is between the fascicle in the post laminar part of the ONH
glial tissue is between the fascicle
why is the infraorbital portion of ON so long?
need wiggle room to look around
where is myelination only located?
increases CSF affect on ON
push on it and it swells
which layer of the meningeal sheath has a lot of BV
PIa- helps profuse parts of the ON
what does glial tissue in the ON do
separates the nerve form the retina, choroid, sclera
Intermediary tissue (of Kuhnt)
Glial tissue separating the retina
Border tissue (of Jacoby)
Glial tissue separating the choroid
Marginal tissue (of Elschnig)
Connective tissue continuous with the sclera
what is the ON inferior to?
olfactory tract and anterior cerebral artery
what is the ON superior and medial to?
what is the ON lateral to?