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Flashcards in Metabolic profile of the eye Deck (35):
1

function of the cornea

ion transport, energy production and an antioxidant system

2

where does mitosis occur in the corneal epitheium

basal epithelial cells

3

what is the critical component in the composition of the cornea ?

water (78% of the composition of the cornea)

4

what counter-acts the uptake of water into the cornea ?

active transport of bicarbonate out into aqueous humor

5

the aqueous humor is

hypertonic with respect to the cornea and maintains corneal transparency

6

prolonged wearing of contacts causes hypoxia which results in

increased lactate production, decreased corneal pH and corneal swelling

7

(t/f) the cornea has the HIGHEST rate of flux through the PPP of any tissue (this supports the anti-oxidant system)

True

8

aqueous humor is secreted by

ciliary processes into the posterior chamber

9

where does the aqueous humor drain into

the canal of schlemm

10

function of aqueous humor

brings nutrients to the cornea and the lens and removes metabolic end products from the cornea and the lens

11

increased intraocular pressure results in ?

glaucoma and damage to the optic nerve

12

what causes primary open angle glaucoma

blockage of the drainage canal

13

what causes angle closure glaucoma (narrow angle glaucoma)

outer edge of the iris blocks entrance to canals there are both chronic and acute forms

14

what causes normal tension glaucoma

optic nerve damage depite normal IOP

15

function of the vitreous humor

support function, metabolic carrier for the retina fibrillar network of proteoglycans

16

holds the proteoglycan bridges apart maintaining sparse meshwork

hyaluronic acid

17

symptoms include flashing lights or floaters

posterior vitreous detachment (PVD)

18

PVD is due to

shrinkage and collapse of the vitreous

19

what are to high content molecules in the lens ?

glutathione and cholesterol

20

________is crucial to lens transparency

water

21

energy production in the lens is mainly

anaerobic glycolysis

22

sorbital pathway is important in

lens (metabolizes high glucose and reduces NADPH levels)

23

10% of glucose metabolism in the lens is via

HMP shunt

24

at high glucose concentrations, glucose is converted to

sorbitol

25

the conversion of glucose to sorbitol depletes

NADPH

26

loss of transparency of the lens and aggregation of proteins is charactertici of

cataract formation

27

mechanism of cataract formation

osmotic uptake of water causes crystallins to aggregate increasing light-scattering

28

cataract formation via oxidative damage ?

oxidaation of sugars to dicarbonyl compounds that may cause oxidation of glutathione, protein SH grps, and inhibition of PPP, oxidation of mem. lipids and may impair membraine transport and permeability

29

mechanism of cataract formation via ionizing radiation

decreased glutathionine, increased calcium which promotes 43Kd protein binding to PM, and crystallins bind to protein forming light scattering aggregates

30

senile cataract mechanism

reduced glutathionine levels
modifcation of lens permeability
modification of lens proteins

31

where are the mitochondria lacking

in the greatest area of visual acuity

32

the retina has a high requirement for

protein and phosphilipid biosynthesis (retina is constantly renewed)

33

macular degeneration is associated with what part of the eye

retina

34

dry AMD

slow progression
cells of macula break down (deposits of drusen)

35

wet AMD

rapid progression
blood vessels grow beneath macula-fragile and leak