18: Vision 1 Flashcards
What is the approximate visible spectrum of wavelength?
400-700nm
What are the two properties of light that we can detect?
Wavelength -variations in wavelengths are perceived as differences in colour
Intensity -wavelengths which have a higher or lower amplitude, which is perceived as brightness
What are the two basic components of the eye?
An optical component
A neural component
What is the role of the optical component of the eye?
Has the main job of collecting and focusing light into the plane of the retina
What is the role of the neural component of the eye?
Converts energy of light into patterned changes of membrane potential that other parts of the brain can decode to generate visual perceptions
What is the role of Sclera?
The white outer layer of the eyeball, known as the “whites” of the eye
Fibrous, opaque, protective layer of the eye containing collagen and elastic fibre
Provides attachment of intraocular inserts
What is the role of the cornea?
Transparent front of the eye that covers the iris, pupil and anterior chamber
Has the role of transmitting light and some of the roles of focusing light
What is the role of the extraocular muscles?
6 muscles attach to the side of the sclera which allow the movement of eyeballs
What is the role of the aqueous humour?
Behind the cornea, clear fluid which is similar to ECF.
Secreted from the ciliary epithelium, a structure supporting the lens
Maintains the intraocular pressure and inflates the globe of the eye
What is the role of the pupil?
Aperture through which light passes. Formed as a hole in the iris which allows light to strike the retina
What is the role of the canal of schlemm
Collects aqueous humour from the anterior interior chamber and delivers it into the episcleral blood vessels via aqueous veins.
What is the role of the lens?
A transparent, biconvex structure which helps to refract light to be focussed on the retina. When it changes shape, it allows the focal distance of the eye to change
It is avascular, and gets nutrients via O2 and diffusion
What is the role of the iris?
Thin, circular structure of the eye which allows the change in diameter of the pupil, which controls the amount of light reaching the retina.
Eye colour is determined by the iris.
Describe the retina
Part of the brain
This is where the photoreceptor cells are located
Describe the choroid
Vascular structure/layer which contains heavily pigmented cells (black so that it can absorb all wavelengths
