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What is the role of the cornea in the eye?
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The cornea refracts light entering the eye. It is transparent, lacks blood vessels, and relies on oxygen diffusion from the air.
How does the iris reflex protect the retina in bright light?
In bright light, the iris reflex causes the pupil to constrict, limiting light entry to protect the retina. This is controlled by the contraction of circular muscles.
What happens to the pupil in low light conditions?
In low light, the pupil dilates to allow more light to enter, ensuring better vision. This dilation is controlled by the contraction of radial muscles.
What does the iris do in the eye?
The iris is the colored part of the eye that regulates the size of the pupil, thereby controlling the amount of light that enters the eye.
Why does the cornea need to be transparent?
The cornea needs to be transparent to allow light to enter the eye unobstructed and to be refracted correctly onto the lens.
What role does the optic nerve play in vision?
The optic nerve transmits visual signals from the retina to the brain.
What are the two types of receptor cells found in the retina and their functions?
The retina contains cone cells, which are sensitive to color and function well in lit conditions, and rod cells, which are more sensitive to light intensity and enable vision in low light but only in black and white.
What muscles control the constriction of the pupil?
The constriction of the pupil is controlled by the circular muscles of the iris.
Describe the function of the pupil in the eye.
The pupil is not a structure itself but a gap in the iris that allows light to pass to the lens.
What muscles control the dilation of the pupil?
The dilation of the pupil is controlled by the radial muscles of the iris.
What are the primary differences between cone and rod cells in the retina?
Cone cells are sensitive to color and function in well-lit conditions, while rod cells are sensitive to light intensity and support vision in low-light conditions but in black and white only.
How does the pupil size adjustment relate to the clarity of vision?
Pupil size adjustment via the iris reflex regulates the amount of light entering the eye, which is crucial for maintaining clear vision and protecting the retina across varying light conditions.
Explain how the eye adapts to different light intensities.
The eye adapts to different light intensities through the iris reflex, which adjusts the pupil size by contracting either the circular muscles in bright conditions or the radial muscles in dark conditions.
What is the fovea and its importance in the eye?
The fovea is a specialized area of the retina packed with cone cells for clear vision.
How does the lens of the eye function?
The lens can change shape to control the refraction strength, thereby focusing light precisely on the retina.
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