The Human Eye: Structure Quiz

What is the function of the cornea in the human eye?

• To control the amount of light entering the eye

• To detect color

• To refract light as it enters the eye

• To carry impulses to the brain

Answer explanation

The cornea's primary function is to refract light as it enters the eye, helping to focus images on the retina. It does not control light entry, detect color, or carry impulses to the brain.

Which part of the eye contains receptor cells known as rods and cones?

• Lens

• Iris

• Retina

• Cornea

Answer explanation

The retina is the part of the eye that contains the receptor cells known as rods and cones, which are essential for vision. Rods detect light and dark, while cones are responsible for color vision.

What is the role of the optic nerve?

• To change the shape of the lens

• To provide protection from external irritants

• To carry impulses between the eye and the brain

• To detect light intensity

Answer explanation

The optic nerve's primary role is to carry impulses between the eye and the brain, transmitting visual information for processing. This makes it essential for vision, unlike the other options which describe different functions.

Which part of the eye is responsible for focusing light onto the retina?

• Sclera

• Conjunctiva

• Pupil

• Lens

Answer explanation

The lens is the part of the eye that focuses light onto the retina. It adjusts its shape to help focus images clearly, unlike the sclera, conjunctiva, and pupil, which have different functions.

What is the function of the ciliary muscle?

• To carry impulses to the brain

• To provide a place of attachment for eye muscles

• To change the shape of the lens

• To detect color

Answer explanation

The ciliary muscle's primary function is to change the shape of the lens, allowing the eye to focus on objects at varying distances. This is essential for clear vision.

Where is the highest density of cones located in the eye?

• Blind spot

• Fovea

• Cornea

• Sclera

Answer explanation

The highest density of cones is located in the fovea, which is the central part of the retina. This area is responsible for sharp central vision and is crucial for activities like reading and recognizing faces.

What is the purpose of the conjunctiva?

• To change the shape of the lens

• To detect light intensity

• To lubricate the eye and provide protection

• To refract light

Answer explanation

The conjunctiva is a thin membrane that covers the eye and inner eyelids. Its primary purpose is to lubricate the eye and provide protection against dust, debris, and microorganisms, making it the correct choice.

Which part of the eye is a transparent disc that can change shape?

• Iris

• Lens

• Retina

• Cornea

Answer explanation

The lens is a transparent disc in the eye that can change shape to focus light onto the retina, allowing us to see clearly at different distances. The iris controls the size of the pupil, while the cornea is the outer layer.

What is the function of the pupil?

• To carry impulses to the brain

• To detect color

• To allow light to enter the eye

• To provide a place of attachment for eye muscles

Answer explanation

The pupil's primary function is to allow light to enter the eye, which is essential for vision. It regulates the amount of light that reaches the retina, enabling us to see clearly in various lighting conditions.

What is the role of the sclera?

• To detect light intensity

• To provide a place of attachment for the muscles that move the eye

• To change the shape of the lens

• To carry impulses between the eye and the brain

Answer explanation

The sclera is the white outer layer of the eye that provides structure and protection. Its primary role is to serve as an attachment point for the muscles that move the eye, enabling eye movement.