The size of the pupil is controlled by the
A
Retina
B
Iris
C
Cornea
D
Lens
Correct Answer: Iris
The size of the pupil is controlled by the activities of two muscles: the circumferential sphincter muscle found in the margin of the iris, innervated by the parasympathetic nervous system: and the iris dilator muscle, running radially from the iris root to the peripheral border of the sphincter.