Seidler's Lecture Flashcards Preview

Neuro 2 exam > Seidler's Lecture > Flashcards

Flashcards in Seidler's Lecture Deck (20):
1

Where to find rhodopsin

photoreceptor in rods

2

Structure of rhodopsin

seven transmembrane
protein opsin linked to 11-cis-retinal

3

Resting State of rhodopsin

Schiff base if protonated

4

Maximum absorption for rhodopsin

500 nm which means Schiff base if protonated

5

Schiff base linkage

retinal linked to lysine 296

6

Signal transduction

light comes in --> rhodopsin --> transducin --> cGMP phosphodiesterase --> allow Na+ in to induce signal

7

Rods

rhodopsin for night vision
high sensitivity and low spatial resolution
*most active in dim light*

8

Cones

for color detection
Three opsins
low sensitivity and high spatial resolution

9

Three opsins

red, green, blue

10

Rod Cell Retinoid Cycle

light induced change from 11-cis to all trans
release of all trans from opsin
reduction from trans-retinal to trans RETINOL
exportation of all trans retinol

11

Cone cycle

Processing proteins at extremely high rates
1 to 1 relationship between cone and ganglion cell

12

Vitamin A deficiencies

Night blindness, Xerophthalmia, keratinization of epithelium in Gi, respiratory and genitourinary tract, skin becomes dry and scaly

13

What controls the body's vitamin A?

beta-carotene

14

Night blindness

vitmamin A deficiency
hurts the rods- so can't see in the dark

15

Xerophthalmia

vitamin A deficiency
abnormal dryness of conjunctiva and cornea of the eye
can't produce tears

16

Macular degeneration- The perfect storm

High respiratory quotient, high lipid content, UV rays
- gets worse with age

17

Macular carotenoids

Lutein and Zeaxanthin

18

Dietary sources of macular carotenoids

green leafy vegetables

19

3 opsins for color detection

red, green, blue

20

What causes color blindness

recombination pathways
rearrangements that may lead to loss of visual pigment