6.11: Activity 9

Integrated Human Anatomy and Physiology Lab Manual I: Fundamentals of Structure and Movement · LibreTexts

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    From LibreTexts, under CC BY-NC 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Plotting the Distribution of Sweat Glands in Thick vs. Thin Skin

    Sweat production from eccrine glands is arguably the most important effector mechanism involved in human temperature regulation during heat stress. Sweat is produced by 2 to 4 million eccrine sweat glands dispersed over the non-glabrous skin regions of the human body.

    This activity involves use an iodine and starch test to compare the eccrine sweat gland density of a thick skin area (like the palm) and a thin skin area (like the forearm).

    Before beginning the experiment, get together with your lab group and formulate a hypothesis based on your previous experience with sweating by forearm and palm.

    1. Write hypothesis of your table group.
    2. Pick up the following supplies:
      • dropper bottle of Lugol’s iodine
      • small squares of white paper that has a dried cornstarch solution on them
      • roll of tape
      • 2 cotton swabs

    Instructions

    1. Using a cotton swab, each member of the lab group should paint (1 \({cm^2}\) area) with iodine on both the palm and on the forearm. Note: use non-writing arm so you can do other parts of the lab while waiting for the experiment to finish.Allow the iodine to dry completely (approximately 3 min).
    2. Use the tape to secure a small piece of bond paper over each dried iodine spot.
    3. Tape the paper directly to your skin. (Note: the area must have dried).
    4. Perform light exercise for 2 to 3 minutes. Wait an additional 5 to 10 minutes. During this time, you can do other parts of the lab.
    5. When the 5 to 10 minutes has elapsed, peel the paper off your skin.
    6. Small, dark colored dots indicate the location of sweat gland. Blue- black color is positive for sweating; white is negative for sweating.Count the number of sweat glands and record in your data table.
    Table \(\PageIndex{1}\): Sweat Gland Count by Location and Group Member
    Member 1 Member 2 Member 3 Member 4
    Anterior forearm
    Palm of the hand

    Analysis

    1. Which area of the body demonstrated to have greatest concentration of sweat glands?
    2. What is the physiological purpose of sweat?

    This page titled 6.11: Activity 9 was last modified on Tue, 01 Sep 2026 01:45:37 GMT and is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Lakshmikanta Sengupta and Susmita Sengupta.