Flashcards in Special Sense Organs Part 2 Deck (33)
What coat/tunic of the eye is an outgrowth of the diencephalon and can be considered a specialized portion of the brain?
nervous tunic or retina
What is the retina in contact with externally? internally?
vitreous body internally
What are the 10 layers of the retina from external to internal?
Pigmented layer (cementing layer), Photosensitive layer (rods and cones), External limiting membrane, Outer nuclear layer, Outer plexiform layer, Inner nuclear layer, Inner plexiform layer, Ganglion cell layer, Nerve fiber layer, and Internal limiting membrane.
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What are the 5 cells involved in the vision pathway?
Rod/Cone, Bipolar, Ganglionic, Multipolar, and cells in Broadman area 17
What do rods and cones synapse with?
Inner nuclear layer
What do bipolar cells from the inner nuclear layer synapse with?
ganglionic cell layer cells
From the Ganglionic cell layer, where do multipolar cells carry info to?
Lateral geniculate body
From where do axons form the optic radiation? where do they synapse?
lateral geniculate body; synapse in BA 17 of occipital lobe
What retinal structures are visible upon funduscopic exam?
optic disc and macula lutea
T/F: the optic disc is the point where the optic nerve attaches to the eyeball, appears white or yellowish, and contains many photoreceptors.
False; contains no photoreceptors
Where do major blood vessels enter the eyeball?
What is the darker area in the center of the fundus?
Where is the fovea centralis?
in the middle of the maculae lutea
Where is the area of clearest vision?
What photoreceptors are found in the macula lutea?
What are the refractory components of the eyeball?
Cornea, Aqueous humor, Lens, and Vitreous body
What refractory component of the eyeball is the most anterior and also the primary refractory structure?
What is the clear fluid secreted by the ciliary processes on the posterior aspect of the ciliary body?
T/F: aqueous humor is secreted into the anterior chamber.
False; secreted into the posterior chamber of the anterior segment (posterior to the iris)
After passing through the pupil into the anterior chamber and then travelling laterally, where does the aqueous humor ultimately leave the eyeball?
through the scleral venous sinus
What results from increased pressure within the anterior segment of the eyeball?
glaucoma which can lead to blindness
Which refractory component of the eyeball is transparent, biconvex, and avascular?
What does increasing the convexity of the lens allow for?
What separates the anterior segment of the eye from the posterior segment?
What is presbyopia?
lens gets harder with age resulting in more difficult near vision
What forms when the lens becomes less and less transparent?
What refractory component of the eye fills the posterior segment, is gelatinous and transparent, and contains a vestigial structure connecting the optic nerve and posterior aspect of the lens? what is this vestigial structure called?
What did the hyaloid canal contain during development and what is its functional purpose in the adult?
fetal hyaloid artery;
serves no purpose in the adult
What are the 3 accessory structures of the eye?
extraocular muscles, lacrimal apparatus, and tarsal glands