eyes - anatomy and embryology Flashcards
what embryological structure does the eye develop from?
optic vesicles of the neural tube
what is the lens placode?
structure formed from thickening of the surface endoderm when the optic vesicles reach said endoderm
what happens when the lens placode starts to invaginate?
the optic vesicle and lens placode forms an optic cup
how many layers does the optic cup have?
2
what is the choroid fissure?
fissure in the inferior wall of the optic cup which allows blood vessels to pass through said cup
what is formed when the choroid fissure doesnt disappear as it normally does?
a gap in tissues develops around it which is called a coloboma
what is formed from the surface ectoderm?
eyelids
conjunctiva
corneal epithelium
what is formed from the mesenchyme?
choroid
stroma of cornea
sclera and extraocular muscles
what forms the lens fibres?
epithelium of lens vesicle
what can happen if the walls of the bony orbit fracture?
contents can herniate into surrounding sinuses
why is orbital fat important?
it cushions the globe and is key in supporting the contents
what forms the fibrous coat of the eye?
cornea
sclera
aqueous humor
what forms the vascular coat of the eye?
iris
ciliary body
choroid
what forms the sensory coat of the eye?
retina
what is the cornea?
the anterior sixth of the eye which is transparent and is a window to allow light rays to enter the eyeball
what is the sclera?
the opaque posterior 5/6 of the eye which gives attachment to the muscles moving the eyeball
what type of epithelium is present in the cornea?
stratified squamous non keratinised?
what is bowmans membrane?
basement membrane of corneal epithelium
what is the stroma of the cornea?
regularly arranged collagen - no blood vessels