the light that gets into it
if their pupil grow big but shrink down fastly
The pupil is allways black. The iris is the colored part.
touching urself at night
your pupils are smallest when there is bright light shining in your eyes they are largest when it is dark, to allow most light possible in
osteoporosis causes people to look as if they are shrinking
dilating
Weathering and erosion
There are many causes that will make ones lungs shrink. Some of the causes may include old age, doing aerobic exercises, and smoking.
Your eyes simply take in more light in order to cope with less available light. Thats why when you look in a mirror after you turn a light on your pupils start to shrink.
The iris is like a contractile structure of smooth muscles which surround the pupil. The sphincter pupillae, one of the smooth muscles categories of the eye, causes constriction of the pupil. The dillator pupillae, the other category of smooth muscles of the eys, causes the pupil to dilate.
The pupil dilates when stimulated by the pinching on the nape of the neck.
If astronauts don't exercise in space, weightlessness eventually causes there muscles to shrink?