A girl has her eyes shut and is standing inside a brightly lit room. what happens to her pupils when she opens her eyes? why?
1. her pupils grow because the muscles relax.
2. her pupils shrink because the muscles relax
3. her pupils shrink because the muscles contract
4. her pupils grow because the muscles contract
The correct answer is:
3. her pupils shrink because the muscles contract.
When the girl opens her eyes, her pupils undergo a constriction response known as the pupillary light reflex. This reflex is controlled by the muscles in the iris, primarily the sphincter pupillae muscle. When exposed to bright light, the muscles contract, causing the pupil to constrict or shrink in size. This helps to reduce the amount of light entering the eye, protecting the sensitive structures within from potential damage.