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80 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the name of the structure where by which light enters the eye?
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The Pupil
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Pg. 133
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How is image focusing of the eye achieved?
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It is achieved by changing the curvature of the lens through contraction and relaxation of the ciliary muscle.
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Pg. 133
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What are the 3 layers of the eye?
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1. The Sclera
2. The Choroid 3. The Retina |
Pg. 133
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Which layer of the eye is the outermost layer?
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The Sclera
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Pg. 133
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What is the name of the clear layer of the outermost layer of the eye?
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The Cornea
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Pg. 133
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What is the Cornea often referred to as?
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It is referred to as the window of the eye.
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Pg. 133
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What layer of the eye is the middle layer?
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The Choroid
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Pg. 133
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What is the name of the reflective middle layer of the eye that some animals have?
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It is called the Tapetum Lucidum
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Pg. 133
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What action does contraction of the radial muscle layer of the iris achieve?
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It dilates the pupil
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Pg. 133
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What kind of axons stimulate contraction of the radial muscle layer of the iris?
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Sympathetic axons
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Pg. 133
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What action does contraction of the circular muscle layer of the iris achieve?
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It constricts the pupil
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Pg. 133
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What kind of axons stimulate contraction of the circular muscle layer?
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Parasympathetic axons
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Pg. 133
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What are 2 drugs that interfere with the nerves that would cause the iris to constrict?
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Atropine and Scopolamine
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Pg. 133
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How is the lens of the eye suspended?
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It is suspended from a muscular process.
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Pg. 133
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What is the muscular process called that suspends the lens of the eye?
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The Ciliary Body
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Pg. 133
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What is the name of the structure that connects the ciliary body to the lens of the eye?
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The Suspensory Ligament
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Pg. 134
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What is the space between the cornea and the iris called?
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The Anterior Chamber
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Pg. 134
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What is the space between the iris, the ciliary body and the lens called?
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The Posterior Chamber
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Pg. 134
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What is the space between the cornea and the iris and the space between the iris, the ciliary body and the lens filled with?
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Aqueous Humor
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Pg. 134
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What secretes the aqueous humor?
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The Ciliary Body
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Pg. 134
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How is the Aqueous Humor drained from the space between the cornea and the iris?
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It is drained by the Canal of Schlemm
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Pg. 134
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What can inadequate drainage of the Aqueous Humor from the anterior compartment lead to and what is this condition called?
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It can lead to an increase in intraocular pressure
This condition is called Glaucoma |
Pg. 134
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What is the portion of the eye located directly behind the lens filled with?
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Vitreous Humor
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Pg. 134
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What are the small bits of protein suspended in the liquid found directly behind the lens called?
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Muscae Volitantes
or Floaters |
Pg. 134
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What is the region of the retina called where retinal axons gather together and exit the retina to form the optic nerve?
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The Optic Disc
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Pg. 134
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What does the optic disc lack?
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It lacks photoreceptors
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Pg. 134
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What is the optic disc also known as and why?
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It is also known as the Blind Spot
Because it lacks photoreceptors |
Pg. 134
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What 2 eye structures refract light?
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The Cornea
And The Lens |
Pg. 134
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What does refraction refer to?
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It refers to the bending of light when light passes from a medium of one density to a medium of a different density.
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Pg. 134
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Which light refracting structures of the eye can change shape?
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The Lens
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Pg. 134
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True or False. The cornea can change shape.
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False. The cornea does not change shape.
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Pg. 134
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Why is the lens transparent?
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1. It lacks blood vessels or (it is Avascular)
2. Its cellular organelles have been destroyed 3. The cell cytoplasm is filled with proteins called Crystallin |
Pg. 135
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Why does the lens need to change shape?
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To keep the image focused on the retina.
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Pg. 135
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What is the term given for the ability of the eyes to keep the image focused on the retina as the distance between the eyes and the object changes?
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Accommodation
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Pg. 135
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What happens to the ciliary muscle of the eye as a person walks closer to an object they are looking at?
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The ciliary muscle contracts, allowing the lens to become thicker.
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Pg. 135
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What is it called when the lens of the eye is as thick as it can get?
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This is the closest that we can focus and it is known as Near Point of Vision
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Pg. 135
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What is the impaired ability of the lens of the eye to thicken known as?
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Presbyopia
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Pg. 135
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What are 3 refractive problems of the eye called?
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1. Myopia
2. Hyperopia 3. Astigmatism |
Pg. 136
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What term is given to refer to the sharpness of vision and is related to the ability of the eye to focus images on the retina?
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Visual Acuity
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Pg. 136
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What does it mean if someone has 20/40 vision?
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It means that they must be as close as 20 feet to see what a normal person could at 40 feet.
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Pg. 136
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What does it mean if someone has 20/10 vision?
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It means they can see at 20 feet what a normal person can see at 10 feet.
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Pg. 136
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What is the condition called where the focus of the image is in front of the retina?
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Myopia
or Nearsightedness |
Pg. 136
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What is the physical problem occurring in Myopia?
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The eye is too long
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Pg. 136
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Which kind of lens would a nearsighted person need to use to correct their problem?
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A Concave lens )(
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Pg. 136
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What is the condition called where the focus of the image is behind the retina?
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Hyperopia
or Farsightedness |
Pg. 136
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What is the physical problem occurring in Hyperopia?
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The eye is too short
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Pg. 136
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Which kind of lens would a farsighted person need to use to correct their problem?
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A Convex lens ()
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Pg. 136
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What condition does an individual have where their cornea, lens or both is not curved symmetrically so that different parts refract the light to different degrees?
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Astigmatism
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Pg. 136
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How is an astigmatism corrected?
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It is corrected with circular lenses that compensate for asymmetry
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Pg. 136
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What are the highly specialized photoreceptor neurons of the eye?
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Rods
and Cones |
Pg. 137
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Which cell in the eye allows for black-and-white vision?
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Rods
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Pg. 137
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What kind of light activates rod cells in the eye?
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Low light intensities
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Pg. 137
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Which cell in the eye allows for color vision and sharper images?
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Cones
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Pg. 137
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What kind of light activates cone cells in the eye?
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High light intensities
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Pg. 137
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Which layer of the eye is like a forward extension of the brain?
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The Retina
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Pg. 137
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What do the highly specialized photoreceptor neurons of the eye stimulate after light activates them?
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Bipolar Cells
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Pg. 137
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What is stimulated by bipolar cells of the eye?
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Ganglion Cells
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Pg. 137
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What do the axons of ganglion cells produce?
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They produce action potentials
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Pg. 137
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Where are the action potential produced by the ganglion cells conducted?
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They are con along the optic nerve to the thalamus, and from the thalamus to the primary visual area of the occipital lobe of the cerebral cortex.
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Pg. 137
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What does each outer segment of the highly specialized photoreceptor neuron of the eye contain?
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It contains hundreds of flattened membranous sacs or discs with the photopigment molecules required for vision.
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Pg. 137
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What are the tips of the outer segments of the rods and cones embedded in?
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Retinal Pigment Epithelium
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Pg. 137
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What does the outer layer of each cell activated by low light intensities contain?
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It contains thousands of molecules of a pigment called Rhodopsin
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Pg. 137
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What does rhodopsin dissociate into in response to light?
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Retinal
and Opsin |
Pg. 137
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What is retinal a derivative of?
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Vitamin A
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Pg. 137
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What is the dissociation of rhodopsin known as?
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The Bleaching Reaction
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Pg. 137
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What are the2 forms of retinal?
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1. The all-trans form
2. The 11-cis form |
Pg. 137
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Which form of retinal can opsin only attach to?
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Only the 11-cis form
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Pg. 137
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What is the gradual increase in photoreceptor sensitivity known as when someone walks from a bright day into a dimmer lighted area called?
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It is called Dark Adaptation
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Pg. 138
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What type of vision do humans and other primates have?
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They have Trichromatic Color Vision
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Pg. 138
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What cones do trichromates have?
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1. Blue
2. Green 3. Red |
Pg. 138
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What type of wavelength of light stimulates blue cones the most?
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Short Wavelengths
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Pg. 138
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What type of wavelengths of light stimulates green cones the most?
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Medium Wavelengths
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Pg. 138
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What type of wavelength of light stimulates red cones the most?
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Long Wavelengths
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Pg. 138
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What is the area of the retina called that we automatically adjust our eyes to so that the image of the object falls directly on this area?
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The Fovea Centralis
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Pg. 138
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What is the large area of the retina where the fovea is located called?
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The Macula Lutea
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Pg. 138
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Which highly specialized photoreceptor neurons does the fovea only contain?
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It only contains cones
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Pg. 138
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How many cones does the retina contain and where are they most concentrated?
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About 6 Million cones
Concentrated most in the fovea |
Pg. 139
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How many rods does the retina contain and where are they mostly located?
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About 120 million rods
Located mostly in the periphery of the eye. |
Pg. 139
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The axons of _______ cells make up the optic nerve that carries visual information to the brain.
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Ganglion
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Pg. 139
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How can stimulation by different rods summate on the bipolar cell?
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Because a number of different rods synapse (converge) with each bipolar cell followed by the convergence of bipolar cells on ganglion cells.
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Pg. 139
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