APPENDIX
Receptive Fields Lab Activity
Directions: Partner up. Using two toothpicks and a small cardboard frame with a 3 × 3 cm
opening, gently touch the toothpicks to the skin in at least six places inside the frame on
various surfaces of your partner’s skin. Make sure your partner is not watching you as you do
so. Try to hold the toothpicks about 1⁄4 in., or 1⁄2 cm, apart between thumb and forefinger.
Randomly alternate whether you touch with one or two. Have your partner respond with a
YES each time he or she correctly identifies if he or she was touched with one or with both
toothpicks. It is important to randomly change so the person being tested does not anticipate
and falsely respond. If the person does not seem sure that it is two, count it as one. Make a
tally mark each time the person says YES in that area and is correct.
As a class, you will determine which areas to test for sensitivity. You will try to identify a
variety of areas, some you believe to be very sensitive, and those you believe to be rather
insensitive.
Have your partner test the same places on you.
Place all data in the data table provided.
Also place your data on the board so a class average can be determined.
, Partner A Partner B Class Average
Anatomical Region Number Sensed Number Sensed Number Sensed
Answer the following questions.
1. Which areas are most sensitive?
2. Did any of these results surprise you? Why or why not?
, 3. What is a receptive field?
4. State at least two reasons that some areas are more sensitive than others.
Reflex Lab Activity
Patellar Tendon Stretch Reflex
This is a common test for spinal cord injury in the reflex arc.
1. Sit in a chair with legs crossed or hanging freely.
2. Have your partner tap the patellar tendon with a reflex mallet and observe the response.
Do this for both legs.
What is the response by the leg to the mallet tap?
Does one leg respond more than the other? If so, which one?
Why do you think there is or may be a difference?
, Achilles Tendon Stretch Reflex
1. Kneel on a chair or stool with your feet hanging free and relaxed and toes pointed
downward.
2. Have your partner tap the Achilles tendon and note the response.
In what way are your responses similar to those in the patellar reflex activity?
In what way are your responses different?
Biceps Muscle Stretch Reflex
1. Sit in a chair facing your partner.
2. Extend your arm forward and bend your elbow joint up 90 degrees (like shaking a fist in
anger—but remain relaxed).
3. Have your partner quickly and firmly (but not forcefully) grab your wrist and pull it
away from you. Note the response.
What is your response to this stimulus?
Explain possible reasons for this reflex.
Extensor Thrust Reflex
This experiment is an exaggeration of this reflex, but it illustrates the mechanism.
1. Stand with both feet several inches apart.
2. Bend your knees very slightly (so your knees are not locked).
3. Palpate1 your quadriceps (anterior thigh) and your hamstrings (posterior thigh) on your
right leg.
4. Lift your left leg off the floor a few inches while you continue to palpate your thigh.
How do the muscles on your right leg feel initially?
How do they compare to one another?
How do the muscles feel when you lift your left leg?
Reciprocal Inhibition
1. Place your forearm on the lab table, palm down, with elbow bent 90 degrees.
2. Push down firmly on the table top. Palpate your triceps and biceps muscles. Try to
contract your biceps.
1
If you don’t know what palpate means, ask an expert or look it up!
Receptive Fields Lab Activity
Directions: Partner up. Using two toothpicks and a small cardboard frame with a 3 × 3 cm
opening, gently touch the toothpicks to the skin in at least six places inside the frame on
various surfaces of your partner’s skin. Make sure your partner is not watching you as you do
so. Try to hold the toothpicks about 1⁄4 in., or 1⁄2 cm, apart between thumb and forefinger.
Randomly alternate whether you touch with one or two. Have your partner respond with a
YES each time he or she correctly identifies if he or she was touched with one or with both
toothpicks. It is important to randomly change so the person being tested does not anticipate
and falsely respond. If the person does not seem sure that it is two, count it as one. Make a
tally mark each time the person says YES in that area and is correct.
As a class, you will determine which areas to test for sensitivity. You will try to identify a
variety of areas, some you believe to be very sensitive, and those you believe to be rather
insensitive.
Have your partner test the same places on you.
Place all data in the data table provided.
Also place your data on the board so a class average can be determined.
, Partner A Partner B Class Average
Anatomical Region Number Sensed Number Sensed Number Sensed
Answer the following questions.
1. Which areas are most sensitive?
2. Did any of these results surprise you? Why or why not?
, 3. What is a receptive field?
4. State at least two reasons that some areas are more sensitive than others.
Reflex Lab Activity
Patellar Tendon Stretch Reflex
This is a common test for spinal cord injury in the reflex arc.
1. Sit in a chair with legs crossed or hanging freely.
2. Have your partner tap the patellar tendon with a reflex mallet and observe the response.
Do this for both legs.
What is the response by the leg to the mallet tap?
Does one leg respond more than the other? If so, which one?
Why do you think there is or may be a difference?
, Achilles Tendon Stretch Reflex
1. Kneel on a chair or stool with your feet hanging free and relaxed and toes pointed
downward.
2. Have your partner tap the Achilles tendon and note the response.
In what way are your responses similar to those in the patellar reflex activity?
In what way are your responses different?
Biceps Muscle Stretch Reflex
1. Sit in a chair facing your partner.
2. Extend your arm forward and bend your elbow joint up 90 degrees (like shaking a fist in
anger—but remain relaxed).
3. Have your partner quickly and firmly (but not forcefully) grab your wrist and pull it
away from you. Note the response.
What is your response to this stimulus?
Explain possible reasons for this reflex.
Extensor Thrust Reflex
This experiment is an exaggeration of this reflex, but it illustrates the mechanism.
1. Stand with both feet several inches apart.
2. Bend your knees very slightly (so your knees are not locked).
3. Palpate1 your quadriceps (anterior thigh) and your hamstrings (posterior thigh) on your
right leg.
4. Lift your left leg off the floor a few inches while you continue to palpate your thigh.
How do the muscles on your right leg feel initially?
How do they compare to one another?
How do the muscles feel when you lift your left leg?
Reciprocal Inhibition
1. Place your forearm on the lab table, palm down, with elbow bent 90 degrees.
2. Push down firmly on the table top. Palpate your triceps and biceps muscles. Try to
contract your biceps.
1
If you don’t know what palpate means, ask an expert or look it up!
