Somatosensory I Flashcards
Exteroceptors sense…
touch, pressure, vibration, pain, and temperature from outside stimuli
Proprioceptors sense
stimuli from muscles, tendons, and joint capsule about our limb position and movement
Interoceptors sense…
stimuli from the viscera about internal changes in our body
Special sensory receptors sense…
our 5 senses
What is sensory transduction?
Conversion stimulus energy into neural/electrical signals in primary afferents
An adequate stimulus is…
A. The minimum amount of a stimulus energy that must be present for the stimulus to be detected 50% of the time
B. The minimum about by which stimulus intensity must be changed in order to produce a just noticeable variation in sensory experience
C. Adequate stimulus for which the sensory receptor is particularly sensitive
C. Adequate stimulus for which the sensory receptor is particularly sensitive
An adequate stimulus has a ____ threshold for activation and a ____ sensitivity to changes in intensity
A. high, low
B. low, high
c. high, high
B. low, high
An absolute threshold is
A. The minimum amount of a stimulus energy that must be present for the stimulus to be detected 50% of the time
B. The minimum about by which stimulus intensity must be changed in order to produce a just noticeable variation in sensory experience
C. Adequate stimulus for which the sensory receptor is particularly sensitive
A. The minimum amount of a stimulus energy that must be present for the stimulus to be detected 50% of the time
Just noticeable difference is…
A. The minimum amount of a stimulus energy that must be present for the stimulus to be detected 50% of the time
B. The minimum about by which stimulus intensity must be changed in order to produce a just noticeable variation in sensory experience
C. Adequate stimulus for which the sensory receptor is particularly sensitive
B. he minimum about by which stimulus intensity must be changed in order to produce a just noticeable variation in sensory experience
T/F: receptor potentials are graded potentials that hyperpolarize the current
False… receptor potentials are graded potentials that depolarize (less negative) the current
What are receptive fields?
an area of the skin where stimulation results in a significant change in rate of action potentials
T/F: receptive fields can vary in size and shape and is dependent on the amount of receptors in the area
True
The ____ the receptive field, the _____ the area of cortical representation
A. bigger, bigger
B. smaller, bigger
C. bigger, smaller
D. smaller, smaller
B. smaller, bigger
C. bigger, smaller… this is an inverse relationship
Ex) the digits have small receptive fields with lots of receptors.
How does the nervous system encode intensity?
frequency (rate of action potentials) and population (# of receptors) coding
What is top down processing?
Interpretation of sensation that is influenced by thoughts and past experiences
What is bottom-down processing?
Perception built from sensory input
Sensory gating is…
A. Assigning sensory inputs in a way where more reliable inputs are assigned a greater weight
B. Filtering out relevant sensory cue’s vs “irrelevant” or “redundant”
C. The ability of the brain
B. Filtering out relevant sensory cue’s vs “irrelevant” or “redundant”
Sensory weighting is…
A. Assigning sensory inputs in a way where more reliable inputs are assigned a greater weight
B. Filtering out relevant sensory cue’s vs “irrelevant” or “redundant”
C. The ability of the brain
A. Assigning sensory inputs in a way where more reliable inputs are assigned a greater weight
The Posterior Columns Medial Lemniscus System carries…
A. Discriminative touch, pressure, vibration, and proprioceptive info from the body to the cortex
B. Discriminative touch, pressure, vibration, and proprioceptive info from the face to the cortex
C. Pain and temperature information from the body to the cortex
A. Discriminative touch, pressure, vibraton, and proprioceptive info from the body to the cortex
T/F: The cuneate fasiculi carries information from the lower limb
False, it carries information from the upper limb
- The gracile fasiculus carries information from the lower limb
At what level does the PCMLS cross?
The medulla
The trigeminal system will cross in the…
Pons
The principal sensory nucleus relays information about…
A. conscious awareness
B. unconscious awareness
A. conscious awareness
T/F: The mesencephalic nuclei carry proprioceptive/kinesthetic information
True
Which of the following are surface mechanoreceptors?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
B. Merkel Cell & D. Meissner’s corpuscle
Which of the following are deep mechanoreceptors?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
A. Pacinian corpuscle, C. Hair Follicles, E: Ruffini corpuscle
Which of the following are rapidly adapting receptors?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
A. pacinian corpuscle
C. hair follicles
D. meissner’s corpuscle
Which of the following are slowly adapting receptors?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
B. Merkel cells
E. Ruffini corpuscle
Which of the following detects tapping & flutter movement in non-hair skin?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
D. Meissner’s corpuscle
Which of the following receptors detects discriminative touch, localization of touch, and determining object characteristics?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
B. Merkel Cell
Which of the following receptors senses deep pressure and vibration?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
A. Pacinian corpuscle
Which receptor senses skin stretch?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
E. Ruffini corpuscle
Which receptor senses movement (direction and velocity of movement)?
A. Pacinian corpuscle
B. Merkel Cell
C. Hair Follicles
D. Meissner’s corpuscle
E: Ruffini corpuscle
C. Hair follicles
What group of fibers has the fastest conduction speed and thickest diameter?
A. group Ia and group Ib
B. group II
c. group III
d. group IV
A. group Ia and group Ib
T/F: the primary somatosensory cortex is somatotopically organized, but it can reorganize in response to experience and injury
True
If a patient experiences a left ACA stroke… what somatosensory deficits would they experience?
- Loss of discriminative touch, pressure, vibration, and proprioception impacting the right lower limb
- The right UL and face remain in tact
If a patient experiences a right ACA stroke… what somatosensory deficits would they experience?
- Loss of discriminative touch, pressure, vibration, and proprioception impacting the left lower limb
- The light UL and face remain in tact
If a patient experiences a left MCA stroke… what somatosensory deficits would they experience?
- Loss of discriminative touch, pressure, vibration, and proprioception impacting right upper limb and face
- Right lower limb remains intact.
If a patient experiences a right MCA stroke… what somatosensory deficits would they experience?
- Loss of discriminative touch, pressure, vibration and proprioception impacting the left upper limb and face
- Left lower limb stays intact
