the eye

Question 1

travel of light through the eye

Answer 1

light enters through the pupil which controls how much light enters. the lens focuses the light rays onto the retina and the retina contains rods and cones

Question 2

visual acuity

Answer 2

ability to tell apart 2 points that are close together

Question 3

retina convergence

Answer 3

several rods connected to each bipolar neurone

Question 4

cones (colour or b/w?, sensitive to?, distributed?, acuity?, types? bipolar connections?)

Answer 4

see in colour, sensitive to iodopsin and bright light, distributed on fovea, high acuity, 3 types, one bipolar connection

Question 5

rods (colour or b/w?, sensitive to?, distributed?, acuity?, types? bipolar connections?)

Answer 5

see in black and white, sensitive to rhodopsin and low light, distributed on peripheral parts, low acuity, 1 type, multiple bipolar connections

Question 6

impulses

Answer 6

• light that hits photoreceptors is absorbed by photo-sensitive pigments
• pigments are bleached and this causes a change in membrane permeability to sodium ions
• generator potential created which causes an action potential if threshold reached
• impulse sent along bipolar neurone to brain

Question 7

what are the three types of cones

Answer 7

blue sensitive cones, red sensitive cones, green sensitive cones - all absorb different wavelengths of light