In this lab, we used the end of a paper clip to determine the sensitivity of different areas of the body. When the density of sensory receptors is high, one should be able to more easily detect touches. When the density is low, sensitivity will also be low, making it hard to distinguish one touch from two touches that are close together.
- Practice touching the ends of the paper clip to you arm. Recognize the different sensations between using both ends and only one end.
- Put the paper clip ends 2 cm apart. Follow steps 3-5 to test the touches on the back and center of your partner’s hand.
- Have your partner close their eyes. Touch the paper clip to the back of your partner’s hand 10 times total. 5 touches use one end and the other 5 touches use two ends. Mix up using one and two ends, do not use the same pattern repeatedly to avoid your partner catching on. After each touch, ask your partner if they felt one or two ends, record their answer in Data Table 1.
- Squeeze the paper clip ends together to be 1.5 cm apart and repeat step 3. Record your partner’s responses in Data Table 1.
- Repeat step 4 with the distance between the paper clips ends at 1 cm, 0.5 cm, and 0.3 cm.
- Use the procedure in steps 2-5 to test the skin on the tip of your partner’s index finger. Record the responses in Data Table 2.
- Repeat the procedure for your partner’s forearm. Pick a location halfway between the wrist and the elbow. Record the responses in Data Table 3.
1) Back of Hand- 1.0 cm Fingertip- 0.3 cm Forearm-0.5 cm
2) Back of Hand-0.3 cm Fingertip-0.3 cm Forearm-0.3 cm
Analyze and Conclude:
- Yes, the results do supports the prediction I made in the Pre-Lab question 1 about which area of skin would have the highest density of sense receptors. I predicted that the fintertips would be the most senstive, according to the data this was correct.
- I think we have a higher density of receptors in some areas of skin than in other areas because we use more areas more often. We use our hands to pick things up, feel texture and temperature, so, it would make sense to have more receptors there than in our forearm.
- Though my partner and I were both able to detect two ends of the clip at least three times at 0.3 cm on our fingertips, but had different sensitivities on the back of our hands and forearm. This shows that we have different desitities of receptors in different areas of our bodies.
- Some factors that could account for vaiation in sensitivity to touch from one person to another are body size, fingerprints, previous possible damage to those body parts, and texture.
- Playing guitar could make one more attentitve and senstive to minor touches. Laying bricks could cause one to develop calluses, making them less sensitive. Any of those activities require the use of sensory neurons, which can affect the receptors.