Development Of The Eye Flashcards
What is the first step of eye development?
The optic vesicle develops and makes contact with the ectoderm
What do the optic vesicles develop from?
The optic grooves
What do the signals from the optic vesicles bring about?
Thickening of the ectoderm to form the lens placode
What happens in week 5 of eye development?
The optic vesicle invaginate along with the placode
What has happened at week 5 of eye development?
The optic grooves have formed as outgrowths of the diencephalon and grow into the overlying ectoderm. The optic grooves expand to form the optic vesicles. These vesicles send signals that thicken the ectoderm to form the lens placode. The optic vesicles invaginate with the placode.
What has happened by 6.5 weeks of eye development?
The optic cup invagination has given two layers - outer and inner. The lens has fully embedded underneath the ectoderm. The lens is hollow.
What does the outer layer of of the optic cup give?
The pigmented layer of the retina
What does the inner layer of the optic cup give?
The neural layer of the retina
What does the anterior firth of the neural retina become?
The pars ceca retinae
What does the pars ceca retinae give?
The ciliary body and iris
What cell layer do the ciliary muscles develop from?
Mesoderm
Where are the ciliary muscles found?
Overlying the ciliary processes
What is the function of the ciliary muscles?
To act on the ciliary processes to impact the shape of the lens. Tighten or loosen suspensory ligaments to allow focus light on the retina.
What does the mesenchyme that overlies the iris do?
Form the sphincter pupillae and dilator pupillae to change the chape and size of the iris
Where are the light receptors and axons for the optic nerve found?
In the posterior 4/5ths of the pars optica retinae
What is the function of the pigmented layer of the retina?
To absorb excess light for focus
In what layer of the retina are the cell bodies of the neurons found?
Outer nuclear layer
What is found in the inner cell layer of the retina?
Bipolar cells that send signals to the ganglion cell layer
How is the optic cup formed?
By invagination of the optic vesicle
What is the invagination along the optic stalk?
Choroid fissure
How does mesenchyme invade the optic cup and what does it form?
Via choroid fissure. Forms network fibres with vitreous humour between
What does the formation of the choroid fissure allow for?
Allows the hyaline artery to access the optic cup. Then extend a branch to the lens vesicle
What happens to the artery before birth?
It breaks down and stops supplying the lens and only supplies the neuroretina
What does the choroid layer of the eyeball develop from?
The deep layer of undifferentiated mesenchyme
What is the sclera?
The outer coating of the eyeball in commutation with the dura matter
How is the anterior chambers of the eyeball formed?
Mesenchyme vacuolization
Where is the posterior chamber?
Between the iris and suspensory ligaments
How does the cornea develop?
The anterior chamber maintains part of its mesenchyme that differentiates and forms the cornea
What does the optic stalk become?
The optic nerve
How does the optic nerve develop?
The optic stalk grows from the diencephalon. The axons start to grow and push into the lumen so it is lost. The edges of the optic stalk fuse and the hyaloid artery becomes trapped inside. The hyaline artery runs through the centre of the optic nerve with axons surrounding it.
