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31 Cards in this Set
- Front
- Back
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The human eye is wrapped in three layers of tissue, name them.
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-The Sclerotic goat;
-The Choroid Goat; -The Retina. |
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What's the function of the Sclerotic goat?
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- Creates the white of the eye;
- Creates the cornea. |
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What's the function of the Choroid goat?
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- It contains melanin, thus forming the iris;
-forms the pupil also. |
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What's the function of the Retina?
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-It creates the inner layer of the eye;
It contains light receptors, rods and cones. |
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What's the function of the cornea?
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- It admits light to the interior of the eye;
- It bends the light rays so that they can be brought to a focus; |
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How is the surface of the cornea kept clean?
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Thanks to the tear glands, they remove dust and moist the cornea.
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What's the function of the iris?
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It reduces the reflection of stray lights within the eye.
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What's the blind spot of the eye?
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It's a spot containing 1 million axons, but no cones or rods.
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Where is the lens located?
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Just behind the iris, it's held in position by zonules, cilinary muscle.
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What's special about cilinary muscles?
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They can relax and contract.
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What happens when the cilinary muscle contracts?
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It decreases in diameter, zonules relax and the lens become spherical.
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What happens when the cilinary muscle relax?
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It increases its diameter, zonules are put under pressure and the lens flatterns.
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What are the symptoms of farsightedness?
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-The eyeball is too short or the lens too flat or inflexible.
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What happens in farsightedness?
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The light rays entering the eye, particularly those from nearby objects will not be brought to focus by the time they hit the retina.
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What is farsightedness medical name?
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Hypertropia.
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What is Hypertropia?
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Farsightedness.
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What's used to fixate the light for people with hypertropia?
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Convex lenses.
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What are the symptoms of nearsightedness?
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The eyeball is too long or the lens is too spherical.
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What happens in nearsightedness?
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The image of distant objects is brought to focus in front of the retina but is out of focus when it strikes the retina.
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Whats the medical term of nearsightedness?
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Myopia.
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What is myopia?
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Nearsightedness.
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What fixates the light for people with nearsightedness?
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Concave lenses.
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What are cataracts?
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Cataracts are clouding of one or both lenses. They're treated by removing the lens and putting a plastic one.
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The iris and lens divide the eye into two main chambers, which?
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-The front chamber which is filled with a watery liquid, the aqueous humor.
-The read chamber which is filled with a jelly like material, the vitreous body. |
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What kind of light-sensitive receptors are found in the retina?
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-Rods;
-Cones that absorb long-wavelength light(red) 565nm. -Cones that absorb medium-wavelength light(green) 535nm. -Cones that absorb short-wavelength light(blue) 440nm. |
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Each type of receptor was its own special_____ for absorbing light.
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Pigment
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What does the pigment on the receptor consist of?
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It consist of a transmembrane protein called opsin coupled to;
the prostetic group, retinal. |
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What is the retinal?
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It's a derivate of vitamin-A and is used for all type of receptors.
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What does lack of vitamin-a cause?
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Night blindness.
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In what do the opsines differ?
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They differ a little in some amino-acid sequences, causing changes in wave-length acceptance.
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The retina contains a complex array of other interneurons, name them.
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Bipolar cells and ganglion that together form a path from the rods and cones to the brain.
A complex array of her inter-neurons that form synapses with the bipolar and ganglion cells and modify the activity. |
