biochemistry of eye in health and disease

Question 1

sclera

Answer 1

• tough elastic white outer layer of connective tissue
• collagen forms 75% dry eight of sclera tissue
• elastin 2%

Question 2

conjunctiva

Answer 2

• semi transparent membrane that covers surface of sclera
• small blood vessels within conjunctiva deliver blood to ocular surface
• secretes sticky mucins
• lubrication
• layer of epithelial cells form mucous membranes

Question 3

functions of aq humour

Answer 3

• continuously produced by cillary body
  to work correctly production must balance with drainage
• transports vit c to anterior eye as antioxidant
• protection against dust

Question 4

cornea

Answer 4

. a vascular
. 02 required for respiration of epithelial cells, diffuse into tissue from blood vessels of conjunctiva and aqueous humor
. oxygen also comes from air when eye is open or from vessels when eye is closed.

Question 5

cornea deficiency

Answer 5

vitamin A deficiency causes :
- xerophthalmia, dryness if conjuctiva and cornea
- night blindness

Question 6

iris

Answer 6

regulates amount of light entering pupil
pupil reduces when circular fibres contract and dilated when radial muscle contracts

Question 7

how much of lens is protein

Answer 7

35%

Question 8

lens
cortical cartaract

Answer 8

protein decrease with age

Question 9

lens
nuclear cataract

Answer 9

water balance remains normal no decrease in protein but increase in protein

Question 10

lens
denaturation due to

Answer 10

unfolding of protein
causes smoking free radicals

Question 11

most common primary malignant intraocular tumour

Answer 11

choroidal melanoma

Question 12

neurotransmission
functions in eye
and outside eye

Answer 12

mitosis
generation of iop
tear secretion

movement
blinking
lid closure

Question 13

transmission of nervous signals by

Answer 13

transport of cations through membranes- action potentials

diffusion of neurotransmitters from one neurons to the next