B1:6 Flashcards
What type of receptors do the eyes contain?
Ones that detect the light
What do these receptors do?
They change the light into electrical impulses and these pass along the optic nerve to the brain
What is binocular vision?
When animals have both eyes facing forward and both eyes are able to focus on the same thing
What does binocular vision enable the animals to do?
They are able to focus and judge distance accurately.
Binocular vision with predators
They are bale to focus and judge distances properly. But they do not have a wide field of view
What is monocular vision?
This is when the animals have eyes on each side of the head.
What does monocular vision enable the animals to do?
The animals have a wider field of view.
Monocular vision with prey
It allows the animals to notice any predators with time to run away. They cannot judge distances very well though
What does the brain do when judging distance?
It compare the images with each eye and If the images are similar, then the brain knows you are looking at something in a distance
What is accommodation?
This is when the lens of the eye changed shape to focus on near or distant objects
How does the ring of ciliary muscle accommodate close viewing?
It contracts
How does the suspensory ligaments accommodate close viewing?
It slackens
How does the lens accommodate close viewing?
It becomes rounded with a fat shape
How does the ring of ciliary muscle accommodate distant viewing?
It relaxes
How does the suspensory ligaments accommodate distant viewing?
It becomes taut
How does the lens accommodate distant viewing?
It becomes flatter with a thinner shape
What is red-green colour blindness?
It is an inherited condition where people cannot clearly tell the difference between red and green colours
Why do people get red-green colour blindness?
Because they do not have the specialised cells in the retina
What is long sightedness?
When people can see distant images clearly, but cannot see close images
What is short sightedness?
It is when people can see close things clearly but not distant
Why are people short sighted?
Because the eyeball is too long and the light rays meet in front of the retina, not on it meaning they final image is blurred
Why are people long sighted?
Because the eyeball is too short meaning the light rays do not meet the retina, therefore the image is blurred
What type of lens is needed to correct short sightedness and how does it do it?
A concave lens is needed and it bends the light rays outwards to meet on the retina
What type of lens is needed to correct long sightedness and how does it do it?
A convex lens to bend the light rays inwards and the light focuses on the retina
