Upgrade to remove ads
Unit 5: Eye
Terms in this set (57)
The automatic adjustment of the eye for seeing at different distances affected by changes in the convexity of the lens.
A defect of an optical system (as a lens) causing rays from a point to fail to meet in a focal point resulting in a blurred and imperfect image. This is caused by a deviation in the curvature of the lens.
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.
Any of the conical photo receptor cells of the retina that function in color vision. There are red, blue and green cones.
The transparent part of the coat of the eyeball that covers the iris and pupil for protection, bends light into an image.
The ability to judge the distance of objects and the spatial relationship of objects at different distances.
A condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than for near objects -- also called farsightedness. The eye ball is too short, corrective lens = convex lens to converge the light. Corrective focal length must be positive.
The opaque muscular contractile diaphragm in front of the lens of the eye, is perforated by the pupil and is continuous peripherally with the ciliary body, has a deeply pigmented posterior surface which excludes the entrance of light except through the pupil and a colored anterior surface which determines the color of the eyes.
Focuses light rays that pass through it in oder to create clear images of objects
A corrective lens is a curved piece of glass or plastic used singly or combined in eyeglasses or an optical instrument (as a microscope) for forming an image by focusing rays of light.
A condition in which the visual images come to a focus in front of the retina of the eye because of defects in the refractive media of the eye or of abnormal length of the eyeball resulting especially in defective vision of distant objects -- also called nearsightedness. Eye is too long, needs a divergent lens with a concave shape and a negative focal length.
The bundle of nerves fibers that carry information from the retina to the brain.
The opening in the iris, which admits light into the inner eye; muscles in the iris regulate its size and control the amount of light entering.
The deflection from a straight path undergone by a light ray or a wave of energy in passing obliquely from one medium (as air) into another (as water or glass) in which its velocity is different.
Detects image focused by cornea and lens- the sensory layer of the eyeball which contains receptors for sight, called rods and cones.
Any of the long rod-shaped photosensitive receptors in the retina responsive to faint light.
White hard area of the eye that protects and covers the eyeball.
Reflects light through the retina.
Clear gel that fills the space between the lens and retina, helps give the eye its shape.
Clear fluid that helps cornea keep round shape.
Optical illusions that occur when looking away after staring intently at a fixed image.
Visual tracks that actually take place in the brain rather than the eye. In an optical illusion images are often mispercieved because of what we know to be true about the images we see on a daily basis sometimes this will trick our brain into not actually processing the image and instead relying on what we know to be true about images this is what is known as an optical illusion. These are significant because it shows the gap between seeing and assuming.
Ability to see things outside of the direct line of vision. Rods are responsible for this.
In the eye that assist in adjustment of lens- aid in accommodation.
A small depression in the retina of the eye where visual acuity is highest. The center of the field of vision is focused in this region, where retinal cones are particularly concentrated.
Is the response of your pupil a reflex or a voluntary action? Describe how this response is controlled by the nervous system.
The response of your pupil is a reflex, this is controlled by the nervous system strictly as means of self protection. In an effort to see as clearly as possible your eye must adjust to the amount of light present while focusing on a certain image. We do not tell our eyes to focus on objects to make them clear when it is dark instead it is a natural reaction.
Describe how what you see can impact other human body systems. Provide at least five specific examples of how your communication with the outside world through your eyes initiates a response in another body system.
What you see impacts your other systems because of the response your brain has to the images it depicts. An image signaling danger may cause your heart to race.
Describe at least three specific ways that we communicate with the outside world and at least three ways (other than sight) in which the world communicates to us.
Through our senses: touch, smell, sound, sight, taste.
Explain how rods and cones in the eye help the police officer in pursuit of a suspect. What other properties of sight help this officer complete his task?
The rods give the officer the vision and the cones help identify certain colors. The rods are responsible for vision at night because they are much more sensitive than cones. Rods are responsible for black and white colors which are much more easily seen in our peripheral vision than vibrant colors. At night, it is nearly impossible to see any color besides black and night which is why the rods allow the officer to adjust his eyes in darkness when needed. Depth perception also helps the officer during a chase because he is able to judge different distances quickly and react. Without depth perception he would be unable to follow and chase the suspect in his car. The rods in his peripheral vision also contribute to when he is chasing the suspect. When the suspect moves his car fast or changes lanes or swerves down a street, the rods and cones in the peripheral vision will allow the officer to detect this change and follow and chase the suspect more accurately.
What is refraction? What does it mean when we say that light is refracted as it enters the eye?
The fact or phenomenon of light, radio waves, etc., being deflected in passing obliquely through the interface between one medium and another or through a medium of varying density.
A refraction means that the light is not bending properly when it passes through the lens of your eye.
Which parts of the eye are most important when it comes to focusing light so we can see a perfect image?
The lens is the most important when it comes to focusing light so that we can see a perfect image. It focuses the light and images on the retina. As well as the pupil- the pupil is responsible for controlling the amount of light to enter into the eye.
Lenses are described as convergent or divergent depending on how they refract light. What is the difference between these two types of lenses? Based on what you have learned, do you think the cornea and the eye lens act together as a convergent or divergent lens? Explain.
Divergent lens are prescribed to people who have myopia or near nearsightedness. They need a divergent lens because their eye ball is too long there for the light needs to come together later in the eye to provide a clear image. In contrast a convergent lens is for those who have too short of an eyeball or hyperopia. The light must come together quickly so it is able to be refracted off of the retina at the proper time.
The cornea and the eye lens act together as a convergent lens, causing the light to bend and hit the retina.
Think about the optical illusions you observed in Activity 10. Explain the relationship between "seeing" with the eye and "perceiving" with the brain.
When the eye sees an image in front of it, the brain quickly assumes it is that of a past image seen. Therefore it assumes it to be something it is not because it has a memory of a similar image.
Do you think it is possible for a person to be blind, but have no problems with the structure and function of his/her eyes? Explain your answer.
Yes because the occipital lobe controls vision, not the eyes. So the eyes can have no problems and a person can be blind if they have serious damage to their occipital lobe.
Glaucoma is an eye disease that affects the pressure of the eye, resulting in optic nerve damage. The aqueous and vitreous humor expand, which then covers the optic nerve, which leads to vision loss. Glaucoma is the second leading cause of blindness.
A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery.
A common eye condition and a leading cause of vision loss among people age 50 and older. It causes damage to the macula, a small spot near the center of the retina and the part of the eye needed for sharp, central vision, which lets us see objects that are straight ahead.
Vision Field Test
The doctor will test this by holding an object up near the side of the patient's face. The doctor will continue to move the object back until the patient cannot see it anymore. If the patient says they are unable to see the object too soon then they have peripheral vision blind spots.
20/20 vision is a set measurement for normal vision this means that you see perfectly. However if you were to have 20/40 vision for example this would mean you see in the clarity 20 feet away that a person with normal vision would be able to see 40 feet away.
How does astigmatism impact the way that you see?
It causes light or images to be distracted bc of the abnormal curvature of the lens.
How is light focused in the eye?
Light rays travel through the curved, clear front surface of the cornea. Then bends the light rays and focuses them into sharp points.
How do the eye and the brain work together to process what we see?
The brain interprets info in a process that begins with the lens and retina and ends with the Cortes of the brain.
The retina, which receives the focused light, has cones and rods which translate color and faint light to chemical and nervous signals so the the optic nerve, which connects to the brain, sends it to the occipital lobe and other parts to be processed into our comprehensible picture.
Trace the path of light from the time it enters the eye to the time it leaves for the brain.
1)Enters cornea, which bends the light.
2)Light passes freely through pupil in the iris.
3)Light passes through vitreous humor.
4)Retina captures light rays, processes them into impulses.
5) Impulses sent to optic nerve via nerve fibers.
6)Optic nerve transmits message to the brain.
Describe two ways in which the cow eye and the human eye differ. How are these differences linked to function?
The cow eye and human eye differ in size and shape. The cow eye has a tapetum present where the human eye does not.
•Human corneas are not as thick
Describe/locate the PUPIL
Hole that lets light into the inner eye.
Describe/locate the RETINA
Layer of light sensitive cells, detects images focused by cornea/lens (screen).
Describe/locate the CORNEA
Covers and protects front of eye, bends light to help make an image.
Describe/locate the BLIND SPOT
Place where optic nerve leaves retina; no light sensitive cells.
Describe/locate the OPTIC NERVE
Bundle of nerve fibers that carries info from retina to brain.
Describe/locate the TAPETUM
Animals w/ good night vision have this; it reflects light back through the retina.
Describe/locate the SCLERA
Thick/tough/white outer covering of eyeball.
Describe/locate the VITREOUS HUMOR
Thick, clear jelly that helps give the eye its shape.
Describe/locate the LENS
Makes image on the retina, flexible so it can change shape and focus.
Describe/locate the IRIS
Muscle controlling how much light enters the eye.
Describe/locate the AQUEOUS HUMOR
Clear liquid under the cornea that helps it keep its rounded shape.
List all of the names for a lens that could cure HYPEROPIA.
(AKA FARSIGHTEDNESS/CAN'T SEE CLOSE UP)
List all the names for a lens that could cure MYOPIA.
(AKA NEARSIGHTEDNESS/CAN'T SEE FAR AWAY)
The Human Eye
THIS SET IS OFTEN IN FOLDERS WITH...
HBS-Unit 3 Test
HBS 3.4.2 Notes for Quiz
YOU MIGHT ALSO LIKE...
HBS 2.3 & 2.4 review
HBS 2.3 & 2.4 review
HBS Eye Anatomy
HBS Eye Anatomy
OTHER SETS BY THIS CREATOR
Region and Digit Names
Muscle Name Terminology
Bony Landmark Definitions