Integrated Science
Name _____________________________
The Senses
STATION #1 -- Skin Sensitivity
5 mm
10 mm
1 mm
2 mm
1. Starting at 10 mm and the subject’s eyes closed,
determine the two-point threshold on the back
of the hand. Randomly alternate the two-point
touch with one-point so that your subject does
not try to second guess you.
2. Repeat this procedure with the palm of the hand,
fingertip, and back of neck.
Which minimum separation is felt as two distinct points?
Back of hand _______ mm
Palm of hand _______ mm
Fingertip
_______ mm
Back of neck _______ mm
STATION #2 – Adaptations of Temperature Receptors
1.
Place one hand in the warm water and the other hand in cold water. Leave them in the
water for about 60 seconds.
2.
Now place both hands in the middle lukewarm water.
Record your observations below.
_____________________________________________________________________
_____________________________________________________________________
STATION #3 –Accommodation of lens
1.
Place a square of wire gauze about one foot in front of your eyes and focus your eyes on
a distant object through the screen.
2.
After closing your eyes momentarily, open them and note whether the screen or the
distant object is in focus.
3.
Repeat this procedure, this time focusing the eyes on the screen before closing them for a
time and then opening them.
Record your observations below.
_____________________________________________________________________
_____________________________________________________________________
STATION #4 – Muscles of the Eye
1.
Observe “retinal disparity” by holding your pointer finger about 6 inches in front of your
face with one eye closed, and then quickly changing eyes and noting the apparent position of the
pencil. Record your observations below.
_____________________________________________________________________
2. Hold your pointer finger out at arm’s length and focus one eye on the tip as it is slowly
brought in to the bridge of the nose. Notice the change in the diameter of the subject’s pupil.
Record your observations below.
_____________________________________________________________________
STATION #5 – Blind Spot
1.
Hold the index card with the cross and circle about 20 inches from your face with the left
eye closed or covered. Focus on the circle; this is most easily done if the circle is
positioned in line with the right eye.
2.
Keeping the right eye focused on the circle, slowly bring the card towards your face until
the cross disappears.
Have your partner measure this distance: ___________ cm
3.
Repeat the above procedure using the left eye focused on the cross (right eye covered or
closed).
Have your partner measure this distance: ___________ cm

Do both your eyes seem to have a “blind spot” at about the same distance? _________

Do you and your partner have the similar distances? __________

What causes the “blind spot?” ________________________________________________
STATION #6 – Conduction of Sound Waves
1.
Strike a tuning fork on the bottom of your shoe to produce vibrations. Do not strike
bench tops.
2.
Place the handle of the vibrating tuning fork against the bony prominence behind the ear.
When the sound has almost died away, move the tuning fork near the outer ear. If there
is no damage to the middle ear (by infection or wax), the sound should reappear.
Record your observations below.
_____________________________________________________________________
STATION #7 – Localization of Sound
1.
Working with a partner whose eyes are closed, strike the tuning fork and ask your partner
to locate the source of the sound. Place the vibrating fork at various positions (front,
back, up, down, left or right side) about a foot from their head.
2.
Repeat the above procedure, but this time have your partner also place a finger in one ear
to plug the ear.
Record your observations below.
_____________________________________________________________________
STATION #8 – Reflexes
1. The knee-jerk, or patellar reflex. The subject should sit on the edge of a table or a high
chair so that his/her leg hangs freely. The observer should locate the patella (knee cap)
and the tendon below it. The tendon should then be stuck sharply with the edge of the
observer’s hand. If properly done, this will produce the so-called knee-jerk – an
involuntary upward motion of the foot and an elevation of the leg.
Describe what happened or problems you had:
2. Motor reinforcement of the knee-jerk. Repeat the above procedure, but have the subject
interlock his fingers and attempt to pull them apart as vigorously as possible just as the
blow is stuck.
a. What effect does this muscular tension have on the reflex action?
b. Explain how clenching your fist during a fight or athletic contest may affect your
reflex responses.
3. Draw a diagram showing the path followed by the nerve impulse in bringing about a
knee-jerk. Use page 682 in your book to help but remember the knee-jerk does not
involve the brain. (Use the back of this page if you need more room)
4. Cilio-spinal reflex. Gently pinch the skin at the nape of the subject’s neck. Note the
reaction of the pupils of his/her eyes.
Describe what happened or problems you had:
5. Sneezing reflex. Stimulate the lining of the nose with some pepper. Be very careful that
it is not inhaled. Try to inhibit this reflex by having the subject press on the upper lip just
below the nose. Describe the results you obtain.
Describe what happened or problems you had:
6. Pupillary reflex. An excellent example of the integration of the nervous system is found
in the reflex activities of the pupils of the eyes. Have the subject close eyes for ninety
seconds and then have him/her open them. Describe the results in your own words.
Describe what happened or problems you had:
QUESTIONS Text Pages 678-684
1.
What is a reflex? (p. 682)
2.
Where are reflex responses controlled?
3.
Name the THREE types of neurons are reflex impulse travels through. (p. 682)
4.
Describe the TWO divisions of the nervous system. (p. 680)
5.
Where are the interneurons located?