How sensitive is skin to touch? The receptors for the sense of touch are scattered over the surface of your entire body, however those receptors are more closely grouped together in certain parts of your body. In this activity you will investigate the distribution and sensitivity of the touch receptors in the human body.
1. Obtain 8 large paperclips, a ruler, and masking tape. 2. Bend paperclip to form a “U” or “V” shape so the ends are 1/2 centimeter apart. 3. Put masking tape across the “legs” of the paperclip to maintain the end distance of your caliper.
Label the paperclip end distance on masking tape 4. Repeat steps 2 and 3 to make calipers with measurements of one, two, three, four and five cm. For wider distances, use sticky tape to hold an opened paperclip onto the zero mark of a ruler. Simply hold another paperclip at the appropriate distance: six cm, seven, eight, nine, ten, twelve, fourteen, sixteen, eighteen, and twenty centimeters. 5. Lab partner must close eyes tightly.
6. Starting with the largest distance, place either one or two ends onto your partners skin (ALTERNATE RANDOMLY so the partner can’t guess!!!) 7. Have lab partner tell you how many ends they can feel. Do this 5 or 6 times. 8. Then try the next smaller distance and repeat steps 6 and 7. 9. Record the smallest distance apart that your partner can be consistently accurate in telling you whether 1 or 2 points being placed onto their skin. 10. Complete each of the body regions in the data table.
11. Calculate the reciprocal as an estimate of the number of receptors. The higher the reciprocal number the more touch receptors in the area. 12. Complete Part 2 test. Your group to decide whether to compare Right side of the body with the Left OR to investigate whether holding and ice bag on the skin area for 10 seconds before testing will affect the results. 13. Graph your results of Body part against Estimate of number of receptors. Use EXCEL or graph by hand.
1. Of the parts of the body tested, which part was best able to distinguish between the closest stimuli?
2. Which part was least able to distinguish between the closest stimuli?
3. What do your results infer about the distribution of touch receptors in the skin?
4. From your lab observations, which part of the body has the greatest number of touch receptors?
5. Is there an advantage for your answer to #4 to have more touch receptors?
6. Was there a difference between Part 1 and Part 2 measurements? Suggest why there may be (or not be) a difference
7. Compare your results with other students. Were there any similarities? Differences?