Name ______


The Integumentary System:

Sweat Pores and Touch Receptors Lab

Observing Sweat Pores

In this lab, you will observe sweat emerging from the pores on your hand.

Procedure:

1.  Obtain a dissecting microscope and put your finger in the observation field and focus the microscope. Examine your finger and then remove it from the field of view. Record your observations in the appropriate space below.

2.  Open and close your fist 75-100 times in quick succession.

3.  Place the same finger as before under the dissecting scope and observe the small droplets of sweat at the openings to the pores. Describe your observations below.

4.  Be sure to get your teacher’s initials to show you did observe your own finger/hand for both parts of this lab. You will not receive credit for using observations from someone else.

Initial Observations / Final Observations

Teacher’s Initials Before ______

Teacher’s Initials After ______

Touch Receptors

The density and distribution of tactile (touch) receptors varies from one part of your body to another. This has a direct effect on your ability to localize touch. Areas with a higher density of receptors should allow you to pinpoint touch more accurately than areas with fewer tactile receptors. Follow the directions below.

Procedure

1.  With your eyes closed, have your partner touch the palm of your hand with a pen. The touch should be gentle enough not to hurt, but firm enough to leave a small mark. Your partner should remove the pen from your palm.

2.  Keeping your eyes closed, try to place the eraser end of a pencil or the tip of the pen on the exact spot touched by your lab partner. Once you think you’ve found it, hold it there.

3.  Have your lab partner measure the difference in distance between the two spots. Record the distance in the table below.

4.  Repeat steps 1 – 3 two more times. Average the results.

5.  Repeat the experiment 4 more times, changing the location to the back of the hand, a fingertip, the ventral surface of the forearm, and the back of the neck. Record and average the results.

6.  Switch roles with your partner so they can also complete the experiment.

Distance Between Touch Spot and Guess
Body Region / 1st Trial / 2nd Trial / 3rd Trial / Average
Palm of hand
Back of hand
Fingertip
Forearm
Back of neck

Analysis

1.  Did the distances get smaller by the third trial? In other words, did you get better at pinpointing the spot touched? Why or why not?

2.  Which area was the most sensitive?

3.  What reason can you give for the difference in sensitivity between the fingertip and the back of the neck? Why is one area more sensitive than the other?

Conclusion: Write a brief conclusion to the sweat pores and touch receptors lab in the space below.