EyeGirl

Animal physiology provides numerous examples of the inherent biological relationship between structure and function. In this film, we explore this relationship by taking a closer look at the structure and function of the eye -- specifically the muscles in the iris. Befuddled by the realization that their eyes seemingly shrink when they look at each other close-up, two students find that their luck is looking up when their inquiries draw the attention of a very special superhero -- EyeGirl.

EyeGirl guides the students through the principles responsible for pupil dilation. A pupil shrinks in response to environmental stimuli such as intense light, or by focusing on nearby objects. The iris changes size based on the reflexes controlled by two smooth muscles -- the sphincter pupillae and the dilator pupillae. Involuntary smooth muscle reacts to internal and external stimuli without conscious effort. The fact that this portion of the eye is made up almost entirely of smooth muscle makes it ideal for rapid contraction in response to stimuli. Utilizing its remarkable structure, the contraction and dilation of the iris is perfect for protecting the sensitive inner working of the eye from intense light and other potentially harmful factors. Furthermore, psychological phenomena such as the presence of an appealing object, fearful sight, or deep concentration causes the pupil to dilate.

Category:

Education

Tags:

• Iris
• Eye
• Superhero
• Eyegirl