Skin Experiments:
A. Use a magnifying glass to view the sweat gland pores located on your fingertips.
B. Somatosensory: For the following experiments use your forearm and then repeat using your palm for the test surfaces. Identify an area about 2 inches by 2 inches. Have another person perform the experiments, while you, the subject, have your eyes closed. Your lab partner should record the number of positive responses within the prescribed area.
1. Temperature: Using a small piece of ice, touch the subject within the areas described above. Note which area has receptors closer together.
2. Pain: Using a straight pin, sterilized with rubbing alcohol, touch the subject within the areas described above. Note which area has receptors closer together.
3. Touch: Using a cotton ball, touch the subject within the areas described above. Note which area has receptors closer together.
4. Pressure: Using a ball point pen cap, touch the subject within the areas described above. Note which area has receptors closer together.
C. Fingerprints: Dermal ridges in the papillary dermis create ridges that form the pattern we identify as fingerprints. Obtain a black ink pad and white piece of paper. Make two finger prints, one of your thumb and the other using one of your other fingers. Compare the patterns seen between the two and see if you can locate the arch pattern, loop pattern, or whorl pattern. The arch pattern has ridges rising over the middle of the finger. A loop pattern has a blind ended ridge called the core along with three sets of ridges that meet at angles of around 120 degrees. The whorl pattern appears as a series of concentric circles. Why are fingerprints still an important tool in forensic medicine and police investigations?
