Human Sense Organs

Human Sense Organs

Eyes

The eye is about as big as a ping-pong ball and sits in a little hollow area (the eye socket) in the skull. The eyelid protects the front part of the eye. The lid helps keep the eye clean and moist by opening and shutting several times a minute. This is called blinking, and it's both a voluntary and involuntary action, meaning you can blink whenever you want to, but it also happens without you even thinking about it.

Sclera

• The white part of the eyeball is called the sclera (say: SKLAIR-uh). The sclera is made of a tough material and has the important job of covering most of the eyeball. Think of the sclera as your eyeball's outer coat.

Multiple Select

Which of the following describes the sclera? Choose all that apply.

• white part of the eyeball

• has the important job of covering most of the eyeball

• helps the eye focus as light makes its way through

• your eyeball's outer coat

Cornea

• The cornea (say: KOR-nee-uh), a transparent dome, sits in front of the colored part of the eye. The cornea helps the eye focus as light makes its way through. It is a very important part of the eye, but you can hardly see it because it's made of clear tissue. Like clear glass, the cornea gives your eye a clear window to view the world through.

Multiple Select

Which of the following describes the cornea? Choose all that apply.

• a transparent dome

• your eyeball's outer coat

• helps the eye focus as light makes its way through

• gives your eye a clear window to view the world

Iris

• The iris (say: EYE-riss) is the colorful part of the eye. When we say a person has blue eyes, we really mean the person has blue irises! The iris has muscles attached to it that change its shape. This allows the iris to control how much light goes through the pupil (say: PYOO-pul).

Multiple Choice

Which of the following statements describes the iris?

• gives your eye a clear window to view the world

• the colorful part of the eye

• your eyeball's outer coat

• a transparent dome

Pupil

• The pupil is the black circle in the center of the iris, which is really an opening in the iris, and it lets light enter the eye. To see how this works, use a small flashlight to see how your eyes or a friend's eyes respond to changes in brightness. The pupils will get smaller when the light shines near them and they'll open wider when the light is gone.

Multiple Choice

The following statements describe the pupil, EXCEPT:

• the black circle in the center of the iris

• it gets smaller when light shines on it

• it gets bigger when the light is gone

• it is the colorful part of the eye

Lens

• After light enters the pupil, it hits the lens. The lens sits behind the iris and is clear and colorless. The lens works much like the lens of a movie projector at the movies. Next time you sit in the dark theater, look behind you at the stream of light coming from the projection booth. This light goes through a powerful lens, which is focusing the images onto the screen, so you can see the movie clearly. In the eye's case, however, the film screen is your retina.

Multiple Select

Which if the following statements describes the lens? Choose all that apply.

• sits behind the iris and is clear and colorless

• job is to focus light rays on the back of the eyeball

• works much like the lens of a movie projector at the movies

• has the important job of covering most of the eyeball

Retina

• Your retina is in the very back of the eye. It holds millions of cells that are sensitive to light. The retina takes the light the eye receives and changes it into nerve signals so the brain can understand what the eye is seeing.

Multiple Choice

Which of the following describes the retina?

• a transparent dome

• the colorful part of the eye

• holds millions of cells that are sensitive to light

• white part of the eyeball

Ciliary Body

• The lens is suspended in the eye by a bunch of fibers. These fibers are attached to a muscle called the ciliary (say: SIL-ee-air-ee) body. It has the amazing job of changing the shape of the lens. That's right — the lens actually changes shape right inside your eye!

Multiple Choice

Which of the following describes the ciliary body?

• has the amazing job of changing the shape of the lens

• sits behind the iris and is clear and colorless

• gives your eye a clear window to view the world

• the black circle in the center of the iris

Optic Nerve

• The optic nerve serves as a high-speed telephone line connecting the eye to the brain. When you see an image, your eye "telephones" your brain with a report on what you are seeing so the brain can translate that report into "cat," "apple," or "bicycle," or whatever the case may be.

Multiple Choice

What is an optic nerve like?

• telephone to the brain

• vacuum cleaner of the brain

• television of the eyes

• watch of the brain

Reference:

https://kidshealth.org/en/kids/eyes.html