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21 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the function of the conjunctiva?
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To secrete a thin film to prevent the eyeball from drying out. It is very vascular and sensitive to pain. It also prevents foreign matter from going all the way to the back of the eye to the brain.
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think pink eye
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What is the whites of the eyes called?
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Sclera
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last part rhythms with maSCARA
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What is the function of the cornea?
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Light hits this first and it bends the light to get it focused on the fovia centralis. In other words, it refracts light. It is an extension of the sclera.
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It does something to the light.
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What is highly vascular and deeply pigmented?
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Choroid. It is the tissue behind the retina.
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What is the function of the ciliary body and the neighboring muscles?
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It forms a muscular ring around the lens. It supports the iris and lens as well as secretes aqueous humor.
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It supports something and secretes something.
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What are the fibers that attach to the cilliary body?
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suspensory ligaments. They support the lens.
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What is an adjustable diaphragm that controls the diameter of the pupil?
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The iris. It is the colored part of the eye.
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This is known as the central opening.
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Pupil
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It is a space not a tissue.
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What is known as the "blind spot"?
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Optic disk, because there are no receptor cells here.
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O.D.
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What is the macula lutea and what is the importance of this area of the eye?
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Directly posterior to the center of the lens, on the visual axis of the eye, is a patch of cells called macula lutea.
The importance is the fovia centralis which is in the middle. It produces the most finely detailed images. |
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What are considered to be the optical components of the eye?
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cornea, aqueous humor, lens and vitreous body. These all admit and bend light (refract) light rays and bring images to a focus on the retina.
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4 things: C, AH, L and VH.
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What are considered to be the neural components of the eye?
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Retina and the optic nerve. They absorb light and encode the stimulus in action potentials transmitted to the brain. The sharpest vision occurs in the region of the retina called the fovea centralis, while the optic disk is the blind spot. The optic disk is where the optic nerve begins.
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Two things: R and O.N.
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What is a near response and what 3 components does it include?
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Is what is needed to focus on closer objects.
It includes: convergence of the eyes, constriction of the pupil and accomodation (thickening) of the lens. |
think eyes doing something, pupil does something and the lens does something.
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What is scotopic vision and is it rods or cones that are responsible for this?
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night vision, rods
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you fish with this
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What is photopic vision and what is responsible for this?
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day with color visions; cones
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you put icecream on one of these.
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What do rods and cones synapse with and why?
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Bipolar cells. This is in response to glutamate secretion. Bipolar cells in turn stimulate ganglion cells. These are the first cells in the pathway that generate action potentials; their axons form the optic nerve.
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think action potentials
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How do the eyes respond to changes in light intensity?
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Light adaptation involves pupillary constriction and pigment bleaching.
Dark adapatation involves pupillary dilation and pigment regeneration. |
how do we adapt to light and dark
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What is the purpose of pigmented epithelium photoreceptors?
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to absorb light that is not first absorbed by receptor cells. It also prevents the light from degrading the visual image by reflecting it back into the eye.
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what do you need to make a good photograph?
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What three types of cones are there?
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blue, green and red cones.
Lack of one or more photopsin results in color blindness. |
these are three primary colors.
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What is hemidecussation and what is the function or purpose?
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It is when half of the fibers of each optic nerve cross over to the opposite site of the brain. This is necessary because of the fact that the right hemisphere controls motor responses on the left and vice versa. Each side of the brain needs to see what is on the side of the body where it exerts motor control
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briefly describe the visual neuron pathway to the brain from the optic tracts through the brain.
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Beyond the optic chiasm, most nerve fibers end in the lateral geniculate nucleus of the thalamus. Here they synapse with third order neurons whose fibers form the optic radiation leading to the primary visual cortex of the occipital lobe. Some fibers also lead to the superior colliculi and pretectal nuclei of the midbrain, which control visual reflexes of the extrinsic eye muscles, pupillary reflexes and accomodation of the lens in near vision
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