The spoke-like muscles that contract to open the pupil are which structure?

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Multiple Choice

The spoke-like muscles that contract to open the pupil are which structure?

When the pupil enlarges, the iris radial muscles contract. These fibers are arranged like spokes radiating from the pupil, and their contraction pulls the iris away from the pupil margin, widening the opening. This dilation is typically driven by sympathetic input. The opposing circular fibers, the iris sphincter, constrict the pupil to make it smaller. Keratocytes are cells in the cornea, and a laminar-flow hood isn’t an anatomy term, so they don’t affect pupil size.

When the pupil enlarges, the iris radial muscles contract. These fibers are arranged like spokes radiating from the pupil, and their contraction pulls the iris away from the pupil margin, widening the opening. This dilation is typically driven by sympathetic input. The opposing circular fibers, the iris sphincter, constrict the pupil to make it smaller. Keratocytes are cells in the cornea, and a laminar-flow hood isn’t an anatomy term, so they don’t affect pupil size.

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