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?
Responses
Her pupils shrink because the muscles relax.
Her pupils shrink because the muscles relax. - no response given
Her pupils shrink because the muscles contract.
Her pupils shrink because the muscles contract. - not selected, this is the correct answer
Her pupils grow because the muscles contract.
Her pupils grow because the muscles contract. - no response given
Her pupils grow because the muscles relax. explain your anwer
Her pupils grow because the muscles relax. The muscles that control the size of the pupils, known as the iris sphincter muscles, are responsible for constricting or dilating the pupils. When these muscles relax, they allow the pupils to enlarge or dilate, allowing more light to enter the eyes.
The correct answer is "Her pupils shrink because the muscles contract." When the girl opens her eyes, the muscles in her irises contract, causing the pupils to constrict or become smaller. This is known as the pupillary light reflex and it serves to regulate the amount of light entering the eyes. In bright light, the pupils shrink to reduce the amount of light entering the eye and protect the delicate structures within the eyes.
In this scenario, when the girl opens her eyes, her pupils actually grow larger. This happens because the muscles in our eyes, specifically the iris muscles, contract or constrict under bright light conditions. This contraction of the iris muscles causes the opening in the center of the iris, called the pupil, to become smaller in size. Conversely, in low light conditions, the iris muscles relax or expand, causing the pupil to dilate or become larger, allowing more light to enter the eye.
The main function of this mechanism is to regulate the amount of light that enters the eye. When exposed to bright light, the pupils shrink to limit the amount of light reaching the sensitive retina at the back of the eye. Conversely, in dim light conditions, the pupils dilate to allow more light to enter and improve visual perception.
Therefore, in the given scenario of a brightly lit room, the girl's pupils would shrink when she opens her eyes, as the iris muscles contract in response to the increased light intensity.