The Eye Flashcards
What is scelra?
Tough white layer surrounding the eye.
What is the choroid?
Dark, pigmented layer containing blood vessels.
What is the fovea?
Opposite lens, highest concentration of rod and cone cells.
What is the blind spot?
Area with no light detecting cells.
What is the optic nerve?
Carries impulses from the eye to the central nervous system.
What is the retina?
Contains rod and cone cells to detect light.
What are suspensory ligaments?
Hold the lens in place.
What is the lens?
Fine focus of light onto the retina.
What is the pupil?
Gap in iris allowing light into the eye.
What is the iris?
Pigmented structure that controls the size of the pupil.
What is the cornea?
Transparent structure that focuses light onto the retina with the lens.
What is the ciliary muscle?
Contracts to change the shape of the lens.
How do you detect an image?
Inverted image is projected onto the retina as light passes through the lens and cornea. Brain corrects the image to make it right way up.
What are rod cells?
Detect light intensity, produce black and white image at low light intensity.
What are cone cells?
Work in bright light, detect three colors (red, green, blue). Color perceived depends on combination of cones activated.
What is the iris reflex in bright light?
Pupil constricts to let less light in, too much bright light damages eyes.
What is the iris reflex in dim light?
Pupil dilates to let more light in.
How does your pupil constrict?
In bright light, radial muscles relax, circular muscles contract, pupil constricts.
How does your pupil dilate?
In dim light, radial muscles contract, circular muscles relax, pupil dilates.
What is accommodation/focus?
Process by which the lens changes shape to focus on near/distant objects.
How does your eye change when looking at a distant object?
Lens is less rounded, ciliary muscles relax, suspensory ligaments tighten, pulls on lens to be flatter.
How does your eye change when looking at a near object?
Lens is more rounded, ciliary muscles contract, suspensory ligaments slacken, lens relaxes into a more rounded shape.
