coordination Flashcards
the function of the eye in focusing on near objects
ciliary muscles contract
suspensory ligaments slacken
this allows the lens to become fatter
light is refracted more
the function of the eye in focusing on distant objects
ciliary muscles relax
suspensory ligaments stretch thin
this allows the lens to become thinner
light is refracted less
how the eye responds in dim light
photoreceptors detect the change in environment (dark) radial muscles contract circular muscles relax pupil dilates more light enters the eye
how the eye responds in bright light
photoreceptors detect the change in environment (light) radial muscles relax circular muscles contract pupil constricts less light enters the eye
explain the reflex action step by step
the stimulus is detected by a pain receptor in the skin
sensory neurone sends electrical impulses to the spinal cord
electrical impulse is passed on to relay neurone in spinal cord
relay neurone connects to motor neurone and passes the impulse on
motor neurone carries the impulse to the muscle to the effector
muscle will contract
adaptations of motor neurone
has long axon to carry impulses
has multi-branched endings to connect many other cells
has myelin sheath on axon for insulation and to speed up rate of impulse transmission
function of cornea
refracts light- bends as it enters the eye
function of iris
controls how much light enters the pupil
function of lens
further refracts light to focus it onto the retina
function of retina
contains the light receptors
function of optic nerve
carries impulses between the eye and the brain
function of ciliary muscles
alters the shape of the lens so that the eye can focus
function of suspensory ligaments
attaches the ciliary muscle to the lens
