So that means in order for us to actually see, we would want to open up the pupil so that more light goes inside our eye and that basically helps us see better. And that's exactly what happens when we enter a room that contains very little light. So the sympathetic nervous system of our autonomic nervous system. So our sympathetic division of the autonomic nervous system innervates one type of smooth muscle inside the iris, known as the radial smooth muscle. And when we are inside a dark room, so under very dark conditions, the sympathetic nervous system basically contracts the radial smooth muscle, which dilates or opens up our pupil. So this iris basically contains the radial smooth muscle that contracts as a result of the sympathetic division of the autonomic nervous system and opens up our pupil.