the retina Flashcards
retina is lined with rows and rows of photoreceptors
these pick up and process light
what are the two main types of photo receptor?
rods and cones
what do rod cells do?
detects light across the middle of the visible light spectrum (blue-green), absorbs less light at the extremities (purple and red)
rod cells are more sensitive to…
low light intensities
which pigment do rod cells use to detect light?
rhodopsin (a protein)
what pigment does cone cells use?
iodopsin
why are there three types of cone cell?
respond to different colours, red cones, blue cones, and green cones which respond to the wavelengths, and each absorb different amounts of red, blue and green
how can the brain perceive colour vision?
by analysing how much red, green and blue light there is
compare different types of photoreceptor:
rod cells have on type and cone cells have three types
rods cells have low intensity light and cone cells sensitive to high intensity light, rod cells sensitive to black and white vision, cone cells, colour vision, pigment rhodopsin vs iodopsin
what are bipolar cells?
once photoreceptors have detected the light, they pass their signal onto bipolar cells
one cone cells have their own…
bipolar cell
multiple rod cells connect to
a single bipolar cell
why do multiple rod cells connect to a single bipolar cell?
allows many low level signals (low level signals) to be pulled into a single signal, 1 rod cell would not be enough to stimulate a whole bipolar cell
what’s the benefit of connecting multiple rod cells to a single bipolar cell?
improves the accuracy of rod cells in low light
what do bipolar cells do?
pass the signal to a sensory neurone which takes the signal to the brain
