Ocular: Retina And Lens Metabolism Flashcards
(15 cards)
Are the GLUT transporter present in the retina tissues insulin dependent? Why?
No, if they were insulin dependent you would go blind during a fast
Which GLUT transporter IS insulin sensitive?
GLUT4 (in adipose and muscle tissue)
What conditions could promote anaerobic glycolysis in the retina?
-contact lens wear
-sleeping
-dry eye
Which health conditions can decrease the blood oxygen level?
COPD, heart/cardiovascular disease, cystic fibrosis
Why are anaerobic conditions detrimental to the retina?
Because the retina needs high energy for optimal function
What does ascorbic acid (vitamin C) do for the retina?
-absorb the UV to protect retina from UV damage
-scavenge free radicals to protect from oxidative damage
What happens in the retina if there is not enough O2?
Lactic acid is produced which can lead to edema
What is the primary energy molecule in the lens?
Glucose -> other sugars can be metabolized but glucose is the best
Do lens cells “slough” or turn over?
No, they remain throughout life
What is required to minimize oxidative damage to the lens?
Tight metabolic regulation to maintain lens clarity
Where are the older fibers located in the lens generally?
More towards the center
Lens cells primary metabolism:
Glycolysis and HMP shunt
What metabolism does the lens epithelium utilize?
MAINLY glycolysis and HMP shunt BUT can also use some TCA and ETC in order to utilize lactic acid production in non-epithelium lens cells
Does the lens have blood flow or circulating fluids?
No
How are lens cells connected and how do they distribute nutrients?
A network of low resistance gap junctions
