14.6 - Photoreceptors Flashcards
How light enters the eye and reaches the photoreceptors How light is converted into an electrical signal by photoreceptors The key features of rods and cones
What is the pupil?
- Adjustable opening
- lets light into the eye
What is the iris?
Coloured part around pupil that adjusts its size
What is the lens?
Clear part that focuses light onto the retina
What is the retina?
Inner lining at back of eye
What are photoreceptors?
Cells that detect light
What is the fovea?
Area in retina full of cone cells for sharp vision
What is the optic nerve?
Nerve sending signals from retina to brain
How is light converted into an electrical impulse?
Light hits photopigments
What pigment do rods contain?
Rhodopsin
What pigment do cones contain?
Iodopsin
What type of vision do rods provide?
Black-and-white
What type of vision do cones provide?
Colour
Where are rods located?
Peripheral retina
Where are cones located?
Fovea
How are rods connected to neurones?
Many rods converge on one bipolar neurone
How are cones connected to neurones?
Each cone has its own bipolar neurone
What is the light sensitivity of rods?
Very light sensitive
What is the light sensitivity of cones?
Less sensitive than rods
What is the visual acuity of rods?
Low
What is the visual acuity of cones?
High
What is visual acuity?
Sharpness of vision and ability to distinguish details
