What is the effect on pupil size during a sympathetic nervous system response?

During a sympathetic nervous system response, the body prepares for a "fight or flight" reaction, which includes various physiological changes aimed at enhancing survival in stressful situations. One of these changes is the dilation of the pupils, a process known as mydriasis.

When the sympathetic nervous system is activated, it releases neurotransmitters like norepinephrine, which bind to receptors in the body. In the eyes, activation of these receptors causes the muscles of the iris to relax, allowing more light to enter and improving visual acuity. This dilation helps individuals to better detect potential threats in their environment, enhancing peripheral vision and overall awareness.

Understanding this response is crucial for EMTs and healthcare providers, as pupil dilation can be an important indicator of an individual's response to stress, pain, or even certain medical conditions.