Certified Cardiac Rehabilitation Professional (CCRP) Practice Test 2025 – Complete All-in-One Guide for Exam Success!

The dilation of pupils is predominantly controlled by the sympathetic nervous system. This system is part of the autonomic nervous system and is responsible for the body's 'fight or flight' response. When the sympathetic nervous system is activated, it prepares the body to respond to a perceived threat or stressful situation. One of the physiological changes that occur during this response is pupil dilation, known as mydriasis, which allows more light to enter the eye, potentially improving vision and awareness of the surrounding environment.

In contrast, the parasympathetic nervous system typically stimulates pupil constriction, facilitating better visual focus on close objects and conservation of energy. While the autonomic nervous system does encompass both sympathetic and parasympathetic responses, it is the sympathetic component that specifically causes pupil dilation. The central nervous system, which includes the brain and spinal cord, primarily processes information and coordinates responses but does not directly control peripheral functions like pupil size.