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32 Cards in this Set
- Front
- Back
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What is light made of?
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particles aka photons
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What is light made of?
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waves aka EM waves
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EM waves....
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two transverse waves at right angles to each other. one is electrical in nature, the other is magnetic
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What is the part of the electromagnetic spectrum?
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light. its is also visible to the human eye.
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Wavelengths of visible light...
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400-700 NM
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light can travel at a constant velocity through a given medium.
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but travel can be impeded moving from one medium to another
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Refraction of light through a _____ reveals that while light is a mixture of all colors of light.
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prism
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What are some of the prisms examples?
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ROY G BIV
while tight is an optical illusion |
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When passing through a curved lens, light is bent to a ____.
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focus
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The closer the object being viewed is to the lens, ....
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the longer the focal distance.
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The focal distance can be kept constant when viewing objects at varying distances by
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changing the shape of the lens.
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What are the external structures of the eye?
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-palpebral fissure
- medial/lateral canthus - eyelid - eyelashes - eyebrows - lacrimal caruncle - sclera - pupil - iris - limbus |
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What are the 3 lateral sections of the eye?
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three tunics
lens optic disc/nerve |
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The two cavities and 3 layers of the eye?
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outer fibrous tunic
- sclera & cornea middle vascular tunic - iris, ciliary body, &choroid inner sensory tunic - neural part -pigmented part |
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Outer Fibrous Tunic
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cornea, sclera, and limbus
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The middle vascular tunic
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iris, ciliary body, and choroid
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The inner sensory tunic
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ora serrata
retina |
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Light/ Dark Adaptation by the Iris
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Sympathetic activation= pupils dilate
- radial dilator contract - sphincter constructores relax |
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Light/ Dark Adaptation by the Iris
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Parasympathetic activation= pupils constrict
- radial diators relax - sphincter constrictors contract |
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What is the organization of the retina?
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- the photoreceptor cells are located at the back of the retina, near the vascular tunic.
- the rods and cones synapse with bipolar neurons which in turn synapse with ganglion neurons - horizontal cells and amicrine cells are neurons that facilitated communication among neighboring rods and cones - all the axons of the ganglion neurons travel together to the optic disc and exits the eyeball as the optic nerve |
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Lens of the eye...where is it located?
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posterior to the cornea and the iris
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what does the lens of the eye do?
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separates anterior and posterior chambers of the eyeball.
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By what is the lens of the eye held by?
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it is held in place by the suspensory ligaments of ciliary bodies.
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What does the lens help in?
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helps to focus light onto retina
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what is accommodation?
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is the process by which the lens adjusts to focus images (changes shape of lens)
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What is the normal visual acuity?
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20/20
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What is accommodation?
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-When the ciliary muscles contract, tension on the ciliary ligaments is reduced and the lens becomes more rounded
- when ciliary muscles relax, tension on the ligaments is transferred to the lens causing it to flatten |
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What are the visual abnormalities?
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- emmetropia: normal vision
- myopia: near-sightness; corrected with a diverging lens - hyperopia: far-sightedness; corrected with a converging lens - astigmatism: bends light differently |
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Rods are what kind of vision?
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black and white
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Cones are what kind of vision?
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color
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What are the 3 characteristics of Rods?
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-very sensitive (can respond to a single photon)
- cannot determine colors - night vision |
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What are the characteristics of Cones?
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- less sensitive
- respond to select wavelengths of light.....red, blue, and green light |
