The Eye Flashcards

All 11 cards in this deck

What is the function of the retina?

It contains the light receptors, which are sensitive to light intensity and colour.

What is the function of the cornea?

A transparent front layer that refracts light into the eye.

What is the function of the iris?

It contains muscles that change the size of the pupil, controlling how much light enters the eye.

What is the function of the optic nerve and the sclera?

The optic nerve carries impulses from the retina to the brain; the sclera is the tough white outer layer that protects the eye.

What is accommodation?

The process of changing the shape of the lens to focus on near or distant objects.

What happens in the eye when focusing on a near object?

Ciliary muscles contract, suspensory ligaments loosen, lens becomes thicker and refracts light rays strongly.

What happens in the eye when focusing on a distant object?

Ciliary muscles relax, suspensory ligaments are pulled tight, lens is pulled thin and only slightly refracts light rays.

How does the eye adapt to dim light?

Muscles in the iris relax/adjust so the pupil dilates (gets bigger), letting more light reach the retina.

In myopia and hyperopia, where do light rays focus, and which lens corrects each?

Myopia: rays focus in front of the retina, corrected by a concave lens. Hyperopia: rays focus behind the retina, corrected by a convex lens.

Other than spectacles, name three technologies used to correct eye defects.

Hard or soft contact lenses, laser surgery to change the shape of the cornea, and a replacement lens in the eye.

True or false? The ciliary muscles contract to make the pupil smaller in bright light.

False. The muscles of the iris change pupil size; the ciliary muscles change the shape of the lens.