Pre-Lab: Testing Sensory Receptors for Touch
Problem What factors affect a person's ability to sense gentle pressure on skin?
Materials bent paper clips, metric ruler
Lab Manual Chapter 31 Lab
Skills Focus Measure, Analyze Data, Draw Conclusions
Connect to the Your nervous system coordinates your response to stimuli from outside your body and inside your body. Sensory receptors react to stimuli by sending impulses to sensory neurons. Each receptor can detect only one type of stimulus. Receptors are classified by the type of stimuli to which they respond. Some respond to light, some to pain, some to chemicals, and so on. Mechanoreceptors are cells that respond to touch, pressure, vibrations, and stretch.
In this lab, you will investigate the mechanoreceptors in your skin that respond to gentle touch. You will compare the relative density of these receptors in three areas of your skin. You will also identify other factors that could affect a person's response to touch.
Review Which division of the peripheral nervous system transmits signals from receptors in your skin to your brain?
Relate Cause and Effect List two reasons why a touch might not produce a nerve impulse?
Infer People who are visually impaired use their fingertips to read books that are printed in Braille. In Braille, each letter of the alphabet is represented by a unique pattern of dots. What feature of the dots allows a reader to distinguish one set of dots from another?
Preview the procedure in the lab manual.
Predict Which area will have the highest density of receptors for gentle pressure—your fingertips, the back of your hand, or your forearm?
Control Variables Why must you have your eyes closed while your partner touches your skin with the bent paper clip?
Predict Will you and your partner have the same density of touch receptors in a given area of skin? Give a reason for your prediction.
Visit Chapter 31 online to test yourself on chapter content and to find activities to help you learn.
Untamed Science Video Hold on tightly as the Untamed Science crew takes you on a quick tour of how animal toxins affect the body.
Data Analysis Investigate the relationship between the color of food and perception of flavor.
Art Review Review your understanding of the structures in the eyes and ears with this drag-and-drop activity.
InterActive Art Watch a nerve impulse move down a neuron.
Visual Analogy Compare an action potential moving along a neuron to a row of falling dominoes.
Art in Motion View a short animation that shows how a reflex arc works.