Questions and Answers
How many layers does the eye have?
Three layers
What are the three layers of the eye?
The sclera, the choroid layer, and the retina.
Which layer is the sclera?
The outermost layer.
How many functions does the sclera have?
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What are the functions of the sclera?
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Describe the physical features of the sclera.
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What is the cornea?
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How many functions does the cornea have?
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What are the functions of the cornea?
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What does the cornea require?
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What is the cornea not supplied with?
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What would happen if there were blood vessels in the cornea?
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How is oxygen absorbed into the cornea?
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Where are nutrients supplied from for the cornea?
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What is the aqueous humour?
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What form is the aqueous humour in?
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What is the second/middle layer of the eye called?
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What does the choroid layer contain?
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What is towards the front of the choroid layer?
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What is the iris composed of?
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What does the lens do?
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Where are the lens located?
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Where are the ciliary muscles located?
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What do the ciliary muscles do?
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The large chamber behind the lens is called the __________.
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What does the vitreous humour contain?
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What does the vitreous humour do?
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Where does the vitreous humour move light?
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What is the innermost layer of the eye called?
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How many different layers does the retina comprise?
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What are the four layers the retina comprises?
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Where does the pigmented epithelium lie?
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What do the pigmented granules in the pigmented epithelium do?
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How many types of light-sensitive cells are there?
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What kind of light do the rods respond to?
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What kind of light do the cones respond to?
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Which light-sensitive cells respond to low-intensity light?
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Which light-sensitive cells respond to high-intensity light?
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What do both rods and cones act like?
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When excited, where is the nerve message passed from rods and cones?
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Where does the bipolar cell relay the nerve message to?
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Where does the optic nerve carry the nerve message to?
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How are rods and cones distributed in the retina?
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What is the name of the tiny depression in the center of the retina?
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What is the most sensitive area of the eye?
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What happens when you look at an object?
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Where are rods with the fovea centralis?
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Are there any rods or cones next to the area where the retina and the optic nerve meet?
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What is the area where there are no rods and cones next to the optic nerve called?
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Study Notes
Structure of the Eye
- The eye consists of three layers: sclera, choroid layer, and retina.
Sclera
- The sclera is the outermost layer of the eye.
- Functions of the sclera include protection and maintaining the eye's shape.
- It is white, fibrous, with the front part forming the clear, bulging cornea, which refracts light toward the pupil.
Cornea
- The cornea is a transparent segment of the sclera that protects the eye and refracts light.
- Without blood vessels, the cornea remains transparent; blood vessels would cause cloudiness.
- Oxygen enters the cornea from gases dissolved in tears, while nutrients come from aqueous humour.
Aqueous Humour
- Aqueous humour is a transparent fluid located in a chamber behind the cornea, supplying nutrients and protecting the lens.
Choroid Layer
- The choroid layer is the second/middle layer of the eye, rich in blood vessels that nourish the retina.
- The iris, located at the front of the choroid layer, regulates light entrance by controlling the pupil size.
Iris
- Composed of a thin circular muscle, the iris acts as a diaphragm to control the pupil's diameter.
- The iris plays a crucial role in regulating the amount of light entering the eye.
Lens
- The lens, located directly behind the iris, focuses images on the retina.
- Ciliary muscles attached to ligaments around the lens adjust its shape for focusing.
Vitreous Humour
- The vitreous humour is a large chamber behind the lens filled with jelly-like material that maintains eyeball shape and allows light passage to the retina.
Retina
- The retina is the innermost layer, containing photoreceptors and composed of four layers: pigmented epithelium, light-sensitive cells, bipolar cells, and optic nerve cells.
Pigmented Epithelium
- This layer lies between the choroid and light-sensitive cells, preventing light scattering with its pigment granules.
Light-Sensitive Cells
- There are two types of light-sensitive cells: rods (respond to low-intensity light) and cones (require high-intensity light and perceive color).
- Both rods and cones function as sensory receptors, transmitting messages to bipolar cells, then to the optic nerve and finally to the central nervous system.
Distribution of Rods and Cones
- Rods and cones are unevenly distributed in the retina.
- The fovea centralis, located at the center of the retina, holds the highest density of cones, resulting in sharp vision.
Fovea Centralis
- The fovea centralis is the most sensitive area of the eye, densely packed with cones.
- When focusing on an object, most light rays hit the fovea centralis, enhancing visual acuity.
Blind Spot
- The area where the optic nerve attaches to the retina lacks rods and cones, creating a blind spot.
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Description
Test your knowledge on the anatomy of the eye with these flashcards. From the layers of the eye to the functions of the sclera, explore essential concepts in ocular structure. Perfect for students looking to enhance their understanding of eye anatomy.