eye structure Flashcards
what is the function of the lens?
to refract light to focus an image - the shape changes according to viewing distance
what is the function of the ciliary muscles?
a ring of muscles which holds the lens, can alter its shape by pulling on tiny tendons
what is the function of the aqueous humour?
a watery liquid between the cornea and lens which refracts light (refractive medium)
what is the function of the cornea?
a transparent tissue that refracts light
what three structures refract light in the eye?
the cornea, aqueous humour, vitreous humour
what is the function of the vitreous humour?
a transparent, jelly-like liquid which fills the eyeball + maintains its shape, refracts light
what is the function and description of the fovea?
the fovea is a ‘dent’ at the back of the eye which can see fine details of colour
what does the retina do?
receives light images, translates them into electrical impulses sent to the brain for interpretation - is the innermost layer of the eye and contains photoreceptors (convert light into signals for the brain) and the fovea (can see fine details of colour)
what is the function of the pupil?
allows light to be let into the eye
what does the conjunctiva do?
lubricates the eye and prevents microbial entrance into the eye
what does the eyelid do?
protects ocular surfaces
what is the function of the optic nerve?
sends messages to the brain
