Eye Embryo

Question 1

Neuroectoderm Derivatives (6)

Answer 1

Optic Cup
   Retina
   Iris Smooth Muscle
   Iris Pigmented Epithelium
   Ciliary Body Epithelium
Optic Nerve

Question 2

Surface Ectoderm Derivatives (2)

Answer 2

Lens

Cornea Epithelium

Question 3

Neural Crest/Mesoderm Derivatives (8)

Answer 3

Sclera
Cornea Stroma
Choroid 
Iris Stroma
Ciliary Body Stroma
Ciliary Muscle
Eye Vasculature
Extraocular Muscles

Question 4

Primordial Eye Structures

Answer 4

Eye comes from diencephalon

External called Optic Vesicle
Internal called Optic Sulcus connected to brain via Optic Stalk
Sulcus forms Optic Cup (ectoderm)

Question 5

Optic Cup Parts (3) and Derivatives

Answer 5

Inner Layer: Neural retina

Outer Layer: Pigmented retina

Rim: Iris pigmented epithelium/muscle and ciliary body epithelium

Question 6

Iris Structures (3) and Origin

Answer 6

Epithelium and Dilator/Constrictor Pupillae Ms from Neural Ectoderm

Stroma from Neural Crest

Question 7

Ciliary Body Structures (3) and Origin

Answer 7

Epithelium from Neural Ectoderm

Ciliary Muscle and Stroma from Neural Crest

Question 8

Aniridia

Cause and Presentation

Answer 8

Caused by Pax6 gene mutation that arrests optic cup rim development

Presents with lack of iris tissue

Question 9

Lens Formation

Answer 9

Starts when optic cup touches surface ectoderm
Lens placode invaginates to form Lens Pit
Pit separates from ectoderm to form Lens Vesicle

Question 10

Cornea Parts (2) and Origin

Answer 10

Epithelium from Surface Ectoderm

Stroma from Neural Crest

Question 11

Lens Cell Types (3)

Answer 11

Anterior Lens Epithelium are cuboidal

Primary Lens fibers are tall columnar cells without nuclei

Secondary Lens fibers are cuboidal and surround lens

Question 12

Congenital Cataracts

Description and Causes (4)

Answer 12

Opaque lens

Caused by genetics, maternal rubella, maternal radiation or Congenital Galactosemia

Question 13

Cornea Development

Answer 13

Lens vesicle induces surface ectoderm to form epithelium

Neural Crest cells form corneal stroma

Question 14

Aqueous Chambers

Location and Humor Supply/Function

Answer 14

Anterior Chamber between iris and cornea
Posterior Chamber between iris and lens

Aqueous Humor comes from ciliary body to nourish lens

Question 15

Eye Blood Vessels (3)

Germ Layer, Development and Supplied Structures

Answer 15

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.

Question 16

Extraocular Muscles

Development with Germ Layer

Answer 16

Prechordal mesenchyme forms pre-otic myotomes

Pre-otic myotomes form muscles from mesoderm

Question 17

Optic Nerve

Germ Layer, Development and Associated Structures

Answer 17

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

Question 18

Congenital Glaucoma

Cause and Effects

Answer 18

CYP1B1 gene mutation or maternal rubella causing abnormal neural crest development
Leads to poor aqueous humor drainage and increased intraocular pressure

Question 19

Coloboma

Answer 19

Incomplete optic fissure closure causing incomplete iris

Question 20

Retinal Detachment

Cause and Associated Conditions

Answer 20

Caused by incomplete fusion of optic cup inner/outer layers

Associated with Down’s Syndrome and Marfan’s Syndrome