Eye biochem.txt

Glucose

• Vitamin A deficiency
• ultimate lack of mucous so there is more keratin synthesis and deposition in the eye

HMP shunt (due to need for NADPH)

Old lens cells that have been compressed together

α,β,γ-crystallines

• γ-crystallines are sensitive to cold and will aggregate together.
• **Can be resolved upon heating up

Loss of near vision

Aqueous humor (since it is not vascularized)

• Increased glucose in serum enters eye
• Glucose reacts with high Km Aldose Reductase
• Production of Sorbitol
• Increase in eye pressure due to water intake
• **aggregation of lens crystallins

• Age
• **your eyes continually grow throughout your life, so the crystallines have more chances of aggregation

• 1) Pressure for globe-like structure
• 2) nutrients for avascular structures

ciliary processes

• When there is less drainage of aqueous humor fluid with high production of the fluid
• Increased pressure in the eye cuts off blood supply

Decrease production of carbonic anhydrase to not produce more aqueous humor (HCO₃^-)

• Mitochondria (in inner layers)
• Vasculature

Rhodopsin

Red, Blue, Green

Night vision/peripheral vision

Color/acute vision

• 1) Protan = red
• 2) Deuteran = green
• 3) Tritan = blue

Destruction of rods and then cones. Starts with peripheral/night vision and goes to loss of acute/color vision.

dark (due to higher Ca²⁺) in the cell from the cGMP that is open in the outer layer of the rods and cones

• cGMP gates close and stop any more Na⁺ and Ca2+ from entering the outer layer
• Na⁺/K⁺ ATPase stays open in inner layer and hyperpolarizes the cells to -65

Metarhodopsin (all-trans-retinal)

Light-Rhodopsin = Metarhodopsin-Transducin = GDP-GTP = Alpha subunit dissociates from Beta and Gamma = t-Alpha GTP dissociates two gammas from PDE = PDE hydrolyzes cGMP to 5'GMP which closes cGMP channels = HYPERPOLARIZATION!

• Sensitive = macula
• Most congested = fovea centralis

Intake L and Z molecules in the diet