Teaching About Integumentary System

Integumentary System

Introduce

Integumentary System

The integumentary system is made up of the skin, hair, and nails. Its main functions are protection, regulation, and sensation. The skin is the largest organ in the human body, and it contains a variety of receptors that sense touch, temperature, pressure, and pain. The Integumentary System infographic provides a colorful representation of the system that’s easy for students to read and understand.

Sensory receptors in the skin are important for perceiving the external environment. The density of these receptors depends heavily on the location on the body. Use Carolina® 2-Point Discriminators to help students explore varying pressure receptor densities at different points. The activity “Cutaneous 2-Point Discrimination” provides a quick, easy procedure to help students learn about some of the functions of their own integumentary systems.

Skin models provide greatly enlarged cross sections that make it easy to visualize the layers of the skin as well as the placement of sebaceous glands and sensory receptors. Prepared microscope slides of skin cross sections are also valuable in the study of the integumentary system. Pressure receptors aren’t the only kind of sensory receptor you can examine. The Carolina® Cutaneous Sensations Kit allows students to test for touch and temperature receptor density. As you wrap up your integumentary system unit, use this review as a study guide.

Build

Cutaneous 2-Point Discrimination

The skin is the largest organ in the human body. Various receptors in the skin detect different stimuli. Mechanoreceptors respond to skin stretch, cold, changes in texture, and deep pressure. Thermoreceptors sense changes in temperature, and highly specialized nociceptors respond to intense stimuli that can trigger reflex withdrawal and pain.

You have probably noticed that cutaneous receptors are not equally distributed throughout the skin. Some places on your body are more sensitive than others. This activity explores the density of mechanoreceptors in the skin on the hand.

Essential Question

How does the density of cutaneous receptors vary on the human hand?

Background

The integration of responses from cutaneous receptors by the brain and spinal cord results in perception of the type and location of sensation. Stimulation of separate nerves 5 to 6 cm apart on the back are often perceived as one touch by the central nervous system. The tongue can distinguish touches as close as 1 mm, and fingertips can discriminate touches 2.5 mm apart.

Materials

Carolina® 2-Point Discriminator (per pair of students)

Procedure

Place the test subject’s hand palm-up and motionless on the desk. Subjects should keep their eyes closed for the duration of the activity.
Set the 2-point discriminator to the closed position, with the pointer at 0 mm.
Touch the subject’s fingertip and ask if 1 or 2 points are felt.
Open the 2-point discriminator to the 2-mm mark and touch the subject’s fingertip again. Record the number of points felt.
Repeat this process until the subject can discriminate 2 distinct points. Record the final distance between points for the fingertip.
Repeat the procedure for the palm of the hand and back of the hand.
Switch roles and repeat the entire procedure for fingertip, palm, and the back of the hand.

Questions

How did the level of discrimination vary by location?
Based on the distance between points, which part of the hand has the highest density of receptors?
What do you think is a reason for the variation in receptor density on the hand?
Identify another area of the human body that you think would have a high density of cutaneous mechanore

Review