Sensation and perception chapter 2 .txt
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What is a visible illumination that is a type of electromagnetic radiation that corresponds with a small slice of wavelengths in the middle of the electromagnetic spectrum?
What is the spatial pattern that varies in brightness and color? These light rays enter our eyes from different locations and allows us to perceive a scene. This is the first step in the visual process in your eyes.
The Optic Array
What is the trade off between lateral vision and the human’s field of view?
Lateral vision has a more narrow range of high resolution depth processing.
What is acuity?
A measure of how clearly fine detail is seen.
What are the extra ocular muscles?
- Superior/inferior rectus
- Medial/lateral Rectus
- Inferior/superior Oblique
How does the extra-ocular muscles work?
- in tandem.
- in synch with each other.
What is the optic axis?
the imaginary diameter line from the front of the eye to the back through the center of the lens.
What are the three membranes of the eye?
Which membrane of the eye is tough and protective, where the visible portion is white?
Outer layer; Sclera
Which membrane of the eye lines the interior of the sclera and contains most of the blood vessels?
Middle Layer; Choroid
Which membrane layer is made up of neurons and includes the sensory receptors for light?
where does the light enter the eye? and what happens?
- Light is refracted to the retina
What is the donut shaped muscle that controls the amount of light that enters through the cornea pass the pupil to the retina?
What are the three chambers of the eye?
- Anterior Chamber
- Posterior chamber
- Vitreous Chamber
Which chamber of the eye contains Aqueous humor(clear fluid)?
Which chamber of the eye contains Vitreous humor(gel like fluid)?
What is intraocular pressure?
pressure within he eye that prevents the eyes from collapsing.
What part of the eye ensures that light is properly focused on the retina?
What is the focal Length?
- How well the lens can refract light. (see slide in chapter 2 for more detail)
- Weak lens = poor refraction with long focal length
- Strong lens = sharp fraction of light and has short focal length
What are Zonule Fibers?
Fibers that connect the lens to the choroid.
What are the tiny muscles connected to the choroid?
how do the ciliary muscles work?
- When relaxed the lens is thing
- when contracted allows for thicker lens
Which part of the human eye transforms images into neural signals which are sent to high visual processing?
Which photoreceptor provides black and white vision in dim light?
Which Photoreceptor provides high-acuity color vision in bright light?
Which cells receive signals from and send signals to photoreceptors and other _____ Cells?
Which cells receive signals from photoreceptors and sends signals to amacrine cells and retinal ganglion cells?
Which cells receive signals from bipolar cells and amacrin cells then sends action potentials to the brain via the optic nerve?
Retinal Ganglion Cells
Which photoreceptor is more sensitive to low levels of light, has poor acuity and best to see dim light?
What is the molecule called that has the ability to absorb light and initiate transduction?
What are the two possible shapes of photopigments?
- all trans
- these are also known as isomers?(not sure about this one)
what is photoisomerization?
- change in the photopigment’s shape
- 11-cis to all-trans
what is photopigment regeneration?
all trans to 11-cis
What is the operating range of RGC’s (retinal ganglion cells) on a bright sunny day?
10 to the 10th power - 10 to the 13th power
what is the process of adjusting retinal sensitivity bright to dark?
What is the property of retinal circuits in which multiple photoreceptors send signals to one RGC?
What is Strabismus?
- when two yes are not aligned with each other
- cross eyed
- causes double image and impairs binocular depth perception
What is Amblyopia?
- Both eyes develop normally
- neural signals from one eye are not processed properly
- Fine vision canon develop in the affect eye.
what is myopia?
- the optic axis is too long
- prevents thinning of the lens to focus light from a distant object
- near sighted
what is hyperopia?
- optic axis is short
- cannot make lens thick
- can see distant objects, but not close
What is cataracts?
- progressive clouding of the lens
- can lead to blindness
- caused by: ultraviolet exposure and side effect of diabetes
- tx: replacement of the lens
What is glaucoma?
- intraocular pressure is too high
- blockage of the openings for the aqueous humor to drain from anterior chamber
what is macular degeneration?
- damage to the photoreceptors in the center of the retina
- causes vision loss
What are the two types of macular degeneration?
- dry- cells degenerate in the pigment of epithelium
- Wet- new blood vessels grow under the retina and leak fluid
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