Eye Embryo Flashcards
Neuroectoderm Derivatives (6)
Optic Cup Retina Iris Smooth Muscle Iris Pigmented Epithelium Ciliary Body Epithelium Optic Nerve
Surface Ectoderm Derivatives (2)
Lens
Cornea Epithelium
Neural Crest/Mesoderm Derivatives (8)
Sclera Cornea Stroma Choroid Iris Stroma Ciliary Body Stroma Ciliary Muscle Eye Vasculature Extraocular Muscles
Primordial Eye Structures
Eye comes from diencephalon
External called Optic Vesicle
Internal called Optic Sulcus connected to brain via Optic Stalk
Sulcus forms Optic Cup (ectoderm)
Optic Cup Parts (3) and Derivatives
Inner Layer: Neural retina
Outer Layer: Pigmented retina
Rim: Iris pigmented epithelium/muscle and ciliary body epithelium
Iris Structures (3) and Origin
Epithelium and Dilator/Constrictor Pupillae Ms from Neural Ectoderm
Stroma from Neural Crest
Ciliary Body Structures (3) and Origin
Epithelium from Neural Ectoderm
Ciliary Muscle and Stroma from Neural Crest
Aniridia
Cause and Presentation
Caused by Pax6 gene mutation that arrests optic cup rim development
Presents with lack of iris tissue
Lens Formation
Starts when optic cup touches surface ectoderm
Lens placode invaginates to form Lens Pit
Pit separates from ectoderm to form Lens Vesicle
Cornea Parts (2) and Origin
Epithelium from Surface Ectoderm
Stroma from Neural Crest
Lens Cell Types (3)
Anterior Lens Epithelium are cuboidal
Primary Lens fibers are tall columnar cells without nuclei
Secondary Lens fibers are cuboidal and surround lens
Congenital Cataracts
Description and Causes (4)
Opaque lens
Caused by genetics, maternal rubella, maternal radiation or Congenital Galactosemia
Cornea Development
Lens vesicle induces surface ectoderm to form epithelium
Neural Crest cells form corneal stroma
Aqueous Chambers
Location and Humor Supply/Function
Anterior Chamber between iris and cornea
Posterior Chamber between iris and lens
Aqueous Humor comes from ciliary body to nourish lens
Eye Blood Vessels (3)
Germ Layer, Development and Supplied Structures
Vessels come from mesoderm/neural crest
Ventral Hyaloid A supplies inner optic cup, optic cup mesenchyme and lens vesicle
Central Retinal A comes from Distal Hyaloid A
Choroidal Vessels come from Ciliary As.
Extraocular Muscles
Development with Germ Layer
Prechordal mesenchyme forms pre-otic myotomes
Pre-otic myotomes form muscles from mesoderm
Optic Nerve
Germ Layer, Development and Associated Structures
From Neural Ectoderm
Neuroblasts form rods, cones and ganglion cells
Optic stalk forms template for nerve
Axons from ganglion cells invade stalk to form nerve
Nerve grows around distal Hyaloid A/V to form Central Retinal A/V
Congenital Glaucoma
Cause and Effects
CYP1B1 gene mutation or maternal rubella causing abnormal neural crest development
Leads to poor aqueous humor drainage and increased intraocular pressure
Coloboma
Incomplete optic fissure closure causing incomplete iris
Retinal Detachment
Cause and Associated Conditions
Caused by incomplete fusion of optic cup inner/outer layers
Associated with Down’s Syndrome and Marfan’s Syndrome
