Lecture 3- How We See 2 Flashcards Preview

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Flashcards in Lecture 3- How We See 2 Deck (9)
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1
Q

What is phototransduction

A

Conversion of light energy to an electrochemical response by the photoreceptors (rods and cones)

2
Q

What do the phtotransduced rods and cones activate

A

Optic nerve cells to generate and action potential

3
Q

Where are the rods and cones located

A

Deep in the retina

4
Q

What is more present cones or rods

A

Rods

5
Q

What is integrated into the cell membrane of the lamellae that surrounds rods and cones

A

Visual pigment- Rhodopsin in rods

Opsins in cones

6
Q

What happen when light rays hit rods

A

The vitamin A compound reacts to from an isomer (from 11-cis to all trans retinal)
Because it goes from bent to straight it cannot fit and rhodopsin splits and bleaches purple
It then activates a cascade or reaction which closes the sodium channel and leads to hyper polarisation and becomes an action potential directed to the brain

7
Q

What is Rhodopsin made of

A

Opsin + 11-cis Retinal

8
Q

What happens to the remaining trans-retinal

A

Converted to cis-retinol and used with opsin to reform Rhodopsin

9
Q

What type of deficiency can affect vision

A

Vitamin A
Night blindness
Abnormal conjunctiva and corneal epithelium

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