1.
What is the main purpose of the pupil?
Correct Answer
D. Shrinks or grows to allow light into your eye.
Explanation
The main purpose of the pupil is to shrink or grow to allow light into your eye. It works like the aperture of a camera, adjusting its size depending on the light conditions to control the amount of light that enters the eye. This helps us see clearly in different lighting situations, from bright sunlight to dimly lit rooms.
2.
The iris is behind the cornea.
Correct Answer
A. True
Explanation
The iris is indeed located behind the cornea. The cornea is the clear, outermost layer of the eye, while the iris is the colored part of the eye that controls the size of the pupil. The iris is positioned behind the cornea and in front of the lens, helping to regulate the amount of light entering the eye.
3.
The sclera is the transparent front part of the eye that covers the iris and the pupil.
Correct Answer
B. False
Explanation
The sclera is not the transparent front part of the eye; that description belongs to the cornea. The sclera is actually the white, opaque part of the eye. Its main function is to provide structure, protection, and support to the eye. The cornea, on the other hand, is the clear, dome-shaped surface that covers the front of the eye, including the iris and pupil, and plays a crucial role in focusing incoming light onto the retina.
4.
The optic nerve is the part of the eye that can be irritating or bothersome.
Correct Answer
B. False
Explanation
The statement "The optic nerve is the part of the eye that gets on the nerves" is false. The optic nerve is actually the part of the eye that transmits visual information from the retina to the brain. It is responsible for carrying the electrical signals generated by the photoreceptor cells in the retina to the visual cortex in the brain, where the signals are processed and interpreted as visual images.
5.
What is the best definition of the retina?
Correct Answer
B. The innermost part of the eye absorbs light and changes it into electrical signals.
Explanation
The best definition of the retina is the innermost part of the eye that absorbs light and changes it into electrical signals. The retina contains specialized cells called photoreceptors that detect light and convert it into electrical impulses that can be processed by the brain. These electrical signals are then transmitted to the brain through the optic nerve, allowing us to perceive visual information. This definition accurately describes the function and location of the retina in the eye.
6.
The optic nerve sends electrical signals to the ________.
Correct Answer
A. Brain
Explanation
The optic nerve is responsible for transmitting electrical signals from the eyes to the brain. These signals contain visual information that is processed by the brain, allowing us to see and interpret the world around us. Therefore, the correct answer is brain.
7.
Which part of the eye does 20% of the focusing?
Correct Answer
A. Lens
Explanation
The lens of the eye is responsible for focusing light onto the retina, which is the part of the eye that detects light and sends signals to the brain for visual processing. The lens can adjust its shape to change the focal length and bring objects into focus. Therefore, it can be said that the lens does 20% of the focusing in the eye.
8.
The pupil _______ in bright light.
Correct Answer
B. Shrinks
Explanation
In bright light, the pupil naturally shrinks. This is because the iris, which controls the size of the pupil, contracts in response to the excess light entering the eye. By shrinking the pupil, the iris helps to regulate the amount of light that reaches the retina, preventing it from being overwhelmed by the brightness.
9.
What is the best definition of the iris?
Correct Answer
D. The colored part of the eye is under the cornea.
Explanation
The iris is the colored part of the eye that is located under the cornea. It is responsible for controlling the size of the pupil and thus regulating the amount of light that enters the eye. The iris contains pigments that give the eye its specific color and can vary in color from person to person.
10.
The retina absorbs light and changes it into electrical signals. Is this statement correct?
Correct Answer
A. Yes
Explanation
The statement is correct. The retina is a layer of tissue located at the back of the eye that contains specialized cells called photoreceptors. These photoreceptors, known as rods and cones, are responsible for absorbing light and converting it into electrical signals. These signals are then transmitted to the brain through the optic nerve, allowing us to perceive and interpret visual information.
11.
The cornea does ________ percent of the focusing of images.
Correct Answer
B. 80%
Explanation
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. It plays a crucial role in focusing light onto the retina at the back of the eye. The cornea is responsible for about 80% of the focusing of images onto the retina. This is because it has a curved shape that helps to bend and refract light as it enters the eye, allowing for clear vision.
12.
If you scratch your eye, you probably scratch the cornea. True or false?
Correct Answer
A. True
Explanation
When you scratch your eye, it is likely that you are scratching the cornea. The cornea is the clear, protective outer layer of the eye that covers the iris and the pupil. Scratching the cornea can cause discomfort, redness, and blurred vision. It is important to seek medical attention if you suspect that you have scratched your cornea, as it can lead to further complications if left untreated.