2.91 The eye Flashcards
What is the Cornea?
Transparent lens that refracts light as it enters the eye
What is the iris?
Controls how much light enters the pupil
What is the Lens?
Transparent disc that can change shape to focus light onto the retina
What is the retina?
contains light receptor cells - rods and cones
What is the optic nerve?
sensory neuron that carries impulses between the eye and the brain
What is the pupil?
Hole that allows light to enter the eye
What is the conjunctiva?
A clear membrane that covers the white of the eye and inside of the eyelids: it lubricates the eye and protects it from outside irritants
What is the cilliary muscle?
A ring of muscle that contracts and relaxes to change the shape of the lens
What is the suspensory ligaments?
ligaments that connect the ciliary muscle to the lens
What is the Sclera?
The strong outer wall of the eyeball that keeps its shape and provides a space of attachment of muscles that move the eye
What is the Fovea?
A region of the retina with the highest density of cones where the eye sees particularly good detail
What are rod cells?
Cells that detect light intensity
What are cone cells?
Cells that detect colour
What happens when the object is close up?
-Cilliary muscles contract
-Suspensory ligaments loosen, therefore the lens gets fatter
-light is refracted more, making the lens focus more on the close object
What happens when the object is far away?
-The ciliary muscles loosen
-Susupensory ligaments tighten, making the lens thinner
-light is refracted less, making the eyes focus on the far object
