Sympathetic nerves________the pupil while parasympathetic nerves _______it.

Answer

To answer the question, we need to fill in the blanks regarding the functions of sympathetic and parasympathetic nerves in relation to the pupil of the eye.

1. **Understanding the Pupil's Function**: The pupil is the opening in the center of the eye that controls the amount of light entering. It can constrict (become smaller) or dilate (become larger) depending on the light conditions.

2. **Role of Sympathetic Nerves**: The sympathetic nervous system is responsible for the body's 'fight or flight' response. When activated, it prepares the body for action, which includes dilating the pupil to allow more light in. This helps improve vision in low-light situations.

3. **Role of Parasympathetic Nerves**: The parasympathetic nervous system, on the other hand, is responsible for 'rest and digest' functions. It constricts the pupil in response to bright light to reduce the amount of light entering the eye, preventing damage and allowing for clearer vision.

4. **Filling in the Blanks**: Based on the roles of these two systems:
- Sympathetic nerves **dilate** the pupil while parasympathetic nerves **constrict** it.

Final Answer: Sympathetic nerves **dilate** the pupil while parasympathetic nerves **constrict** it.

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