Applied Anatomy and Physiology of the Orbit and the Eye Flashcards
What are the 3 coats of the eye ball?
Fibrous coat
Vascular coat
Sensory coat
What are the different layers in the histology of the cornea?
1) Epithelium
2) Bowman’s membrane
3) Stroma
4) Descemet’s layer
5) Endothelium
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What is the classification of the epithelium of the cornea?
Stratified squamous non-keritinised
What is the Bowman’s membrane?
Basement membrane of corneal epithelium
What is the stroma?
Regularly arranged collagen
Are there any blood vessels in the stroma?
No blood vessels
How many layers form the endothelium of the cornea?
Single layer (normally 2500 cells/mm2)
How is transparency maintained in the cornea?
Histologically by the regular arrangement of collagen in stroma
No blood vessels
Endothelium layer having a pump that actively keeps the aqueous humor out
What is the advantage of the cornea having no blood vessels for a corneal graft?
Lesser chance of foreign antigens being recognised by the recipient so lesser chance of the graft being rejected
What is Schlemm’s canal?
Circular lymphatic like vessel in the eye that collects aqueous humor from the anterior chamber and delivers it into the episcleral blood vessels
What is the trabecular meshwork in the eyeball responsible for?
Responsible for draining the aqueous humor from the eye via the anterior chamber
What is the histology of the retina (and choroid)?
1) Pigment epithelial layer
2) Layer of rods and cones
3) Outer limiting membrane
4) Outer nuclear layer
5) Outer plexiform layer
6) Inner nuclear layer
7) Inner plexiform layer
8) Ganglion cell layer
9) Nerve fibre layer
10) Inner limiting membrane
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What is the choroid?
Vascular layer of the eye lying between the retina and sclera
What is the choroid made up of?
Fenestrated blood vessels of varying diameter which supply the outer layers of retina with blood by diffusion (inner layers get blood from branches of central retinal artery)
How do the inner and outer layers of the retina get blood?
Inner - branches of central retinal artery
Outer - Diffusion from choroid