Flashcards in Anatomy-The Orbit Deck (205)
In the orbit, the medial walls are (blank) to each other and the lateral walls are (blank) to each other
What is the outpocketing of the forebrain that induces a thickening of the surface ectoderm which will form the lens placode or vesicle?
What do we consider CN 1 and CN2?
not true cranial nerves
Where do columns stop?
in the midbrain, therefore there are no columns in the forebrain
What is the cornea formed by?
the surface ectoderm
What does the visual retina do?
absorbs light and reduces the amount of bounding around of light
What does the diencephalon form first before forming all the layers of the retina as well as the retinal pigment epithelium and parts of the iris and ciliary body?
the optic cup
What does the optic cup form?
all the layers of the retina as well as the RPE and parts of the iris and ciliary body
What is the muscle of the ciliary body formed by?
mesenchyme that invades the optic cup
What all does the mesenchyme of the eye form?
ciliary muscles, sclera and choroid
The (blank) is the white of the eye, is the opaque, fibrous, protective, outer layer of the eye containing collagen and elastic fiber
The (blank) is the vascular layer of the eye, containing connective tissue, and lying between the retina and the sclera.
When the dura reaches the back of the orbit it separates into 2 layers; what are they?
meningeal and periosteal
Which layer of the dura goes to the undersurface of the bone of the top of the orbit?
What happens to the meningeal layer of the dura when it reaches the orbit?
it follows the optic nerve and then is continuous with the sclera
Where does the cornea come from?
surface ectoderm and underlying infiltrating mesenchyme
Lens arises from the (blank)
What all does the optic cup give rise to?
most of the eye, retina, iris
(blank) invading the area of the optic cup forms smooth muscle, sclera and choroid.
Cornea comes from (blank)
Most severe eye defects are associated with malformation of the (blank)
brain or cranial cavity
(blank) is a relatively common defect associated with incomplete closure of the choroid fissure, a groove that develops for the invaginating hyaloid artery which later regresses and only remains in the optic nerve as the central artery.
What is the hyaloid artery and what happens to it?
it runs from within the optic nerve to the lens to provide nutrition to the lens in the fetus, but regresses before birth to form the central artery of the optic nerve.
What does the hyaloid artery run through?
The choroid fissure. This is what will remain in colomboma because it fails to close resulting in an abnormality.
Each orbit has what kind of shape?
Where is the orbital margin?
Where is the apex of the orbit?
at the base
the optic canal
THe medial walls of the orbit are parallel while the lateral walls of the orbit are at right angles to each other, what does this mean?
this means that the your orbits are facing at angles while your globe is facing straight ahead which means that your optic nerve will be entering medially in your orbit and the fovea will be more lateral
Most of the muscles to the eyeball, will arise from where and attach where and what does this mean?
the back of the orbit, and attach medially. They will be adductors!
What are the bones of the orbit?