In the second week of the Dissection & Scientific Drawing Club, taught by former TPS teacher Virginia Friedman, students explored cow eyes, which have many traits in common with human eyes. Sketching the specimens helps both to slow down our examination and to observe carefully and critically.
After sketching the exterior of the eye, looking at the cornea, sclera ("white" of the eye), fat and muscle tissue, and the optic nerve, students dissected the eyes in order to examine the pupil, iris, lens, retina, and other interior structures.
Unlike humans, cows have horizontal pupils and a tapetum, which is an iridescent layer behind the retina that is common in nocturnal animals and helps to reflect additional light in the eye. (This is why some animals' eyes shine/glow at night.) We also talked about why humans are among the only animals that show the whites of their eyes on a regular basis. Upcoming specimens include sheep hearts, frogs, grasshoppers, and earthworms.