Eye Anatomy & Physiology

How does the visual cortex correct the image seen on the retina? It corrects the upside-down and reversed image.

How many photoreceptors are there approximately in one eye? About 125 million

What are photoreceptors? Sensory receptors that pick up light and send images to the brain as nerve impulses.

What are the four things that reflect light in the eye? 1. Cornea 2. Aqueous Humor 3. Lens 4. Vitreous Humor

What are the primary colors that cones detect? Red

Green

What are the two jobs of the fluids in the eye? 1. Give shape to the eye. 2. Refract light entering the eye.

What are the two types of photoreceptors? Rods and cones

What are the two ways a person sees an object? 1. The object is giving off light. 2. Light waves from another source bounce off it into the eye.

What happens to the image on the retina if the shape of the eye is normal? Light waves are focused sharply upon the retina.

What is astigmatism? A condition where some areas of the cornea are fine and others are distorted.

What is hyperopia? Farsightedness

where the image focuses behind the retina.

What is myopia? Nearsightedness

where the image focuses in front of the retina.

What is the blind spot in the eye? The area where the optic disc is located

which has no photoreceptors.

What is the function of the extraocular muscles? They move the eye inside the eye socket.

What is the function of the lens in the eye? It focuses light entering the eye.

What is the function of the optic nerve? It carries axons from the retina to the base of the brain

transmitting images.

What is the primary function of cones? They deal with color and provide sharpest vision.

What is the primary function of rods? They are more sensitive to light and see gray

black

What is the process called when light rays bend to be focused? Refraction

What is the role of the aqueous humor? It provides nutrients and maintains the shape of the front of the eye.

What is the sclera? The tough

white outer wall of the eyeball.

What is the vitreous humor? A watery fluid that helps keep the eyeball spherical.

What provides 75% of the total refractive power of the eye? The cornea

What type of lens causes light waves to converge? Convex lens

What type of lens causes light waves to diverge? Concave lens

Where is the fovea located and what is its significance? Located in the center of the retina

it contains virtually all cones and provides the sharpest vision.