lesson 4 the eye Flashcards
the eye is what
a sense organ
the eye contains what
receptors sensitive to both light intensity and also the colour of light
light rays pass through where
and what is it called
the transparent front of the eye
called the cornea
what is the job of the cornea
to start the focussing of light rays
the light rays then pass through where
the pupil, in the centre of the iris
what is the iris
the coloured part of the eye
the light rays (after the pupil) then pass through where
the lens
what is the job of the lens
to focus the light rays onto the back of the eye
one key feature of the lens is what
it can change its shape which allows us to focus on distant or near objects
when the lens can change its shape which allows us to focus on distant or near objects, this is called what
accommodation
after the light rays are now focused where (after the lens)
at the back of the eye which is called the retina
what does the retina contain
receptor cells for light
the receptor cells in the retina allow us to detect what
light intensity and light colour
the receptor cells in the retina, then send what
electrical impulses down the optic nerve to the brain
the white part of the eye is called what
the sclera
the sclera’s tough outer structure does what
protects the eye
what works with the lens
ciliary muscle
suspensory ligaments
together the ciliary muscle and suspensory ligaments allow us to do what
focus on distant or near objects
what is the pupil
the space in the centre of the iris, where the light passes through
if you are in a dark room, the amount of light entering the eye is now low, meaning what
the drop in light intensity is sensed by light receptors in the retina and these send electrical impulses to the brain
the brain then does what (dark room)
sends electrical impulses to specific muscles in the iris
the brain sends electrical impulses to specific muscles in the iris, then what (dark room)
the muscles contract, causing the pupil to become larger, this now allows more light to enter the eye
in a dark room eye scenario is it a reflex action
no as it does not involve the brain
in a bright room what effect would there be from the dark room
an opposite effect as the reflex causes the pupil to become smaller
the reflex causing the pupil to become smaller reduces what
(opposite from dark room effect)
the amount of light entering the eye and protects it from damage
