The nerves system Flashcards
light rays are refracted by the…
the cornea and lens
what does the retina contain?
light receptors. some are sensitive to different colours
what does binocular vision do?
binocular vision helps to judge distances by comparing the images from each eye. The more different they are the nearer the object
how can the eye focus light from distant or near objects? what is this called?
by altering the shape of the lens. This is called accommodation
what do your eyes have to do to focus on a distant object?
the ciliary muscles relax and the suspensory ligaments tighten so the lens has a less rounded shape
what do your eyes have to do to focus on a near object?
the ciliary muscles contract and the suspensory ligaments slacken so the lens regains a more rounded shape due to its elasticity
what is accommodation?
altering the shape of the lens to focus on near or distant objects
what do the ciliary muscles do?
they control suspensory ligaments
what does is a ligament?
a short band of tough, flexible fibrous connective tissue which connects two bones or cartilages or holds together a joint.
what does the pupil allow?
light rays to enter the eye
what does the coloured iris do?
controls the amount of light entering the eye
what does the outer cornea do?
refracts the light rays
what does the convex lens do?
refracts light rays and focuses light onto the retina
what do the suspensory ligaments do?
alter the shape of the lens in focusing
what happens on the retina?
a focused image is formed, which is sensitive to light
what does the optic nerve do?
carries nerve impulses to the brain to judge what to do next
what is good and bad about having monocular vision?
they have a wider field of view but are poor at judging distances
what is good and bad about having binocular vision?
they judge distances better but have a narrower field of view
what do sense organs do (receptors)?
keep us informed of what is happening. They detect different stimuli and generate nerve impulses to transmit information to the brain
what do ears do?
detect sound and are used for balance
what do our noses do?
smell chemicals in the air