The iris is the colored part of the eye surrounding the pupil that controls the amount of light entering the retina. It adjusts the size of the pupil based on light intensity through muscle contractions.
5 Must Know Facts For Your Next Test
The iris contains two sets of smooth muscles: the dilator pupillae and sphincter pupillae.
It plays a crucial role in regulating light exposure to photoreceptors in the retina.
Eye color is determined by the pigmentation within the iris, primarily melanin.
The autonomic nervous system controls its function, with sympathetic nerves causing dilation and parasympathetic nerves causing constriction.
Damage or disease affecting the iris can lead to conditions like anisocoria (unequal pupil sizes) or iritis (inflammation).
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Related terms
pupil: The central opening in the iris that allows light to enter the eye.