Cornea

Question 1

Definition

Answer 1

Cornea is a transparent, avascular, watch-glass like structure

Question 2

Histology (6layers)

Answer 2

Epithelium 
Bowman's membrane
Corneal storma
Dua's layer
Descemet's membrane
Endothelium

Question 3

Blood supply

Answer 3

Avascular

Question 4

Nerve supply

Answer 4

Anterior ciliary arteries- ophthalmic division of the 5th cranial nerve

Question 5

Primary physiological functions of cornea

Answer 5

To act as a major refracting medium

To protect the Intraocular contents

Question 6

Corneal transparency

Answer 6

Peculiar arrangement of corneal lamellae
Peculiar refractive index of corneal lamellae with variation less that 200 micrometer
Avascularity of cornea
Relative state of dehydration which is maintained by the barrier effects of epithelium and endothelium and the active Na-K ATPase pump of the endothelium
Swelling pressure of the storms which counters the imbibition effect of IOP
Corneal crystallins i.e. Water soluble proteins of keratocytes

Question 7

Metabolism of cornea

Answer 7

Epithelium and endothelium

Question 8

Source of nutrients

Answer 8

Solutes enter the cornea by either simple diffusion or active transport through aq humour and by diffusion from the perilimbal capillaries

Oxygen derived directly from air through the tear film.

Question 9

Respiratory quotient

Answer 9

1%