3.2.4 More than Meets the Eye

Label the eye

1. Retina

2. Iris

3. Cornea

4. Pupil

5. Aqueous Humor

6. Lens

7. Vitreous Humor

8. Sclera

9. Tapetum

10. Optic Nerve

11. Blind Spot

Retina

The light-sensitive layers of nerve tissue lining the most posterior chamber of the vertebrate eye

What is the function of the retina?

It receives images and send them as electric signals through the optic nerve to the brain

What is the function of the iris?

Determines how much light to let in the eye

Cornea

The transparent part of the coat of the eyeball that covers the iris and pupil

What is the function of the cornea?

It admits light to the interior eye

What is the function of the pupil?

Admits light into the interior of the vertebrate

Aqueous Humor

The fluid that fills the space between the lens and the cornea

What is the function of the aqueous humor?

It maintains intraocular pressure, keeping the eye’s shape

What is the function of the lens?

Refracts light to be focused on the retina

Vitreous Humor

The clear, viscous substance that fills the eyeball behind the lens

What is the function of the vitreous humor?

It maintains the eyeball’s spherical shape, supports the retina, and acts as a shock absorber

Sclera

The white external layer of the eyeball

What is the function of the sclera?

Protects the inner eye from trauma, maintains the shape of the eye against external pressure, and provides an attachment point for the extraocular muscles

What is the function of the tapetum?

Enhances night vision by acting as a mirror

What is the function of the optic nerve?

The vital cable connecting the eye to the brain, transmitting visual information via electrical impulses

Blind Spot

The small circular area in the retina where the optic nerve enters the eye that is devoid of rods and cones and is insensitive to light

What is the function of the blind spot?

It provides necessary pathways for nerve fibers to carry visual information to the brain

What does the brain have to do due to the curves of the eyes?

The curves of the eye changes the direction of light entering it, so the image projected on the retina is upside down, so the brain has to invert it. The brain also has to layer the two images from your retinas to create the 3D image in your mind and give you depth perception

Why is the retina so important?

It is the sensory layer of the eyeball, which contains receptors for sight: rods and cones

Rods

Any of the long rod-shaped photosensitive receptors in the retina responsive to faint light

Cones

Any of the conical photosensitive receptor cells of the vertebrate retina that function in color vision

Choroid

A spongy membrane full of vessels located underneath the sclera

Vitreous Body

A transparent gel-like substance that maintains eye shape, filling the space inside the globe of the eye

Fovea Centralis

A small area with a high density of cone photoreceptor cells, allowing for sharpness of vision

Conjunctiva

Helps protect the eye and plays a role in tear production, with very small blood vessels within it