Sensory Physiology activity Flashcards
TWO-POINT DISCRIMINATION steps and results
With the subject blindfolded, use a blunt tipped compass or calipers to apply moderate pressure
a. Back of neck
b. Fingertip
c. Palmar surface of forearm
d. Lips
e. Palm of hand
f. Calf of leg
5, 10, 15, 20 mm
most
b. Fingertip
d. Lips
e. Palm of hand
just right
c. Palmar surface of forearm
a. Back of neck
worst
f. Calf of leg
PUNCTIFORM DISTRIBUTION OF SENSORY RECEPTORS steps and results
Draw a 20 mm x 20 mm square at the back of the subject’s forearm and subdivide it into 16 smaller squares, blindfolded volunteer
stimulate square with hot and cold nail 4 times with varying degrees of pressure
more cold receptors than heat receptors
LOCALIZATION OF STIMULUS steps and results
While the subject’s eyes are closed, touch the skin of the back of the hand of the subject lightly with the pointed end of a soft lead pencil. Be sure to leave a mark. ask the volunteer to touch it. Use a ruler to measure the error in mm.
cheek > back of the hand > forearm
ADAPTATION AND AFTERIMAGE steps and results
With the volunteer wearing a blindfold, two warmed coins were placed at the same area on both forearms. Then, the volunteer was asked every 5 seconds if the coin was still felt. When the coin was no longer felt by the volunteer, time was taken note of. Both of the coins are then pressed down equally, and one was removed. The volunteer was asked which coin was taken. A rubber band was then placed over her head and was timed for 3 minutes. The band was removed after.
still felt the sensation after
RELATIVE SENSORY PERCEPTION steps and results
10o C, 30o C and 40o C water
Immerse the index finger of the right hand in the 40o C water while simultaneously putting the
index finger of the left hand in the 10o C water. Maintain this for 2 minutes
dunk in 30o C after
results
10o C water felt warmer in 30C
40o C water felt colder in 30C
TASTE STIMULUS steps and results
Dry the subject’s tongue
Blindfold the subject then place a pinch of sugar at the tip of his tongue
Rinse mouth with water and repeat the procedure, this time using salt instead of sugar
record time of taste
The volunteer tasted the salt granules immediately after placing it on their tongue, while it took 10.87 seconds for her to taste the sugar granules
salt - As the ions get in contact with the saliva, they undergo complete dissociation due to the polar nature of water.
Sugar (C12H22O11) - has covalent bonds consisting of numerous hydroxyl groups. In order for it to dissolve, it requires to create hydrogen bonds with the surrounding water
TASTE LOCALIZATION steps and results
Dry the subject’s tongue by blotting with gauze or tissue and mouth breathing for a few seconds
(a) tip, (b) right side, (c) left side, (d) center and (e) back.
salt - all corect
tonic - all correct
umami - center only
sucrose - almost all
acetic acid - all
taste regions are false
Olfactory Fatigue And Adaptation steps and results
Have the blindfolded subject press one nostril shut
Hold a leaf of oregano under the open nostril
Continue this until he claims to no longer smell it
The receptors’ responsiveness decreased, reducing the signals sent to the brain, effectively decreasing the intensity of the smell of the oregano leaf. adapting.
Olfactory Stimulus steps and results
Have a blindfolded subject smell the following one after the other on one side of the nostril
Repeat the procedure for the other nostril
Sugar molecules are generally odorless while the oregano leaf and orange juice contain volatile aromatic compounds that the olfactory receptors are able to detect.
Auditory Acuity steps and results
- This should be performed in a quiet room.
- Have the subject close one ear with his finger and close his eyes.
- Hold a watch in line with the open auditory meatus.
- Gradually move the watch away until he ceases to hear the ticking.
The test assesses whether a reduced hearing distance can be observed from the patient as it might indicate conductive or sensorineural hearing loss.
RINNE’S TEST steps and results
Strike the prongs of the tuning fork against your palm or your heel.
press the base of the tuning form against the mastoid portion of the subject’s left temporal bone (behind the ear) bone conduction
immediately place the prongs of the fork 2 cm away from the external auditory meatus of the left ear and ask the subject to note if the sound can still be perceived air conduction
The air conduction’s significance is through its amplification of sound in the middle ear, testing for the capability of the ear canal, tympanic membrane, and ossicles to allow sound to reach the cochlea. Whereas bone conduction, bypassing the external and middle ear directly reaches the cochlea, hence no amplification occurs.
otherisw, its a neural problem
Weber’s Test steps and results
unilateral hearing loss is present in the patient’s diagnosis. The volunteer responded with the sound of the tuning fork being heard equally in both ears
This impairment is most likely due to any present interruption along the auditory pathways, where the Weber test lateralizes to the unaffected ear, allowing the good ear to hear better.
Visual Accommodation steps and results
volunteer looks at far and near objects, pupil is measured
The volunteer reported that the pupil size was larger (5mm) and dilated at a focus with a far object outside the window. While smaller (4mm) when focused at a closer distance
Near Point steps and results
Hold a pencil at arm’s length in front of you, focusing your eyes on the tip.
Bring the pencil slowly closer to your eyes
The near point is a test used for the evaluation of binocular vision, and having a result greater than 10 centimeters is likely due to the reduced accommodation ability of the patient.
Binocular Vision And Space Perception steps and results
Hold a cube 3 inches in front of your nose and focus your eyes on it.
Close the left eye, observe, then open it but close the right eye this time and observe again
When they overlap, the brain is able to synthesize it into one image with the addition of allowing us to perceive the depth and distance of the object by determining the different views each eye has of said object
double vision stops and the object is moved slightly
Blind Spot steps and results
- Get an index-card size piece of white paper and draw a 1 cm cross and a 0.5 cm diameter dot
about 3 inches apart on a horizontal plane. - Close your left eye and focus your right eye on the dot, holding the paper about 15 inches in front
of your right eye. You should be able to see the cross at the side without moving your focus on
the cross. - Slowly bring the paper closer. Soon the cross will disappear.
This is a result of a blind spot. Towards the back of our eye is the retina which is composed of many light-sensitive cells, but there is a portion of the retina wherein no light receptors are present
NEGATIVE AFTERIMAGES steps and results
Look at the light bulb inside the box for about 30 seconds then shift your gaze quickly to a blank white surface., then red, blue, green yellow
White
Purple with dark blue rim on outer edges
Red
Dark purple (supposedly green dapat)
Blue
Black and Grey
Green
Dark purple with splotches of greenish colors
Yellow
Dark blue with purple and green tones in the middle
