Lecture 9: Introduction to the Sensory System Flashcards
True or False: Discriminative touch is required to recognize size, shape, and texture of objects and their movement across the skin
True
True or False: Tactile sensitivity is greatest on hairless skin of fingers, palm of hand, soles of feet, and lips
True
_____: Sense of static position and movement of limbs and body
A. Discriminative Touch
B. Proprioception
C. Nociception
D. Temperature Sense
B. Proprioception
_____: Perceived as pain or itch; signals tissue damage or chemical irritation
A. Discriminative Touch
B. Proprioception
C. Nociception
D. Temperature Sense
C. Nociception
Pain results from electrical activity transmitted by specific receptors known as _____
nociceptors
____ sensations involve fine aspects of touch while ___ sensations involve cruder sensations
A. protopathic; epicritic
B. epicritic; protopathic
C. epicritic; epicritic
D. protopathic; protopathic
B. epicritic; protopathic
True or False: Epicritic sensations are mediated by ENCAPSULATED receptors while protopathic sensations are mediated by BARE NERVE ENDINGS
True
Which sensations are localizable and discriminative?
Which sensations are poorly localizable and non-discriminiative?
Epicritic
Protopathic
_____: Receptors concerned with conscious appreciation of sensations from external stimuli to our body
A. Exteroceptors
B. Proprioceptors
C. Interoreceptors
A. Exteroceptors
____: Receptors concerned with info about relative position of our body in space - proprioception and how our body is moving in space
A. Exteroceptors
B. Proprioceptors
C. Interoreceptors
B. Proprioceptors
____ proprioception information is relayed to the cerebral cortex
_____ proprioception information is relayed to the cerebellum
Conscious proprioception
Unconscious proprioception
True or False: Interoreceptors are concerned with processing visceral information
True
What are the two type of superficial mechanoreceptors?
A. Merkel disc / Ruffini Endings
B. Ruffini Endings / Pacinian Corpuscle
C. Meissner’s / Pacinian Corpuscle
D. Merkel Disc / Meissner’s Corpuscle
D. Merkel Disc / Meissner’s Corpuscle
What are the two type of deep mechanoreceptors?
A. Merkel disc / Ruffini Endings
B. Ruffini Endings / Pacinian Corpuscle
C. Meissner’s / Pacinian Corpuscle
D. Merkel Disc / Meissner’s Corpuscle
B. Ruffini Endings / Pacinian Corpuscle
Which of the following mechanoreceptors signals pressure and shape of object?
A. Meissner’s Corpuscle
B. Merkel Disc
C. Pacinian Corpuscle
D. Ruffini Ending
B. Merkel Disc
Which of the following deep mechanoreceptors responds best to vibratory stimuli?
A. Meissner’s Corpuscle
B. Merkel Disc
C. Pacinian Corpuscle
D. Ruffini Ending
C. Pacinian Corpuscle
Which of the following is a deep mechanoreceptors that senses lateral movement or stretch of skin, thereby contributing to perception of shape of grasped objects
A. Meissner’s Corpuscle
B. Merkel Disc
C. Pacinian Corpuscle
D. Ruffini Ending
D. Ruffini Ending
True or False: Proprioceptors detect changes in position and movement
True
Proprioceptors are mediated by which four receptors?
- Cutaneous mechanoreceptors (Ruffini)
- Joint Receptors
- Muscle spindles
- Golgi tendon organs
True or False: Warm and cold receptors have distinctive receptive fields
True
At extreme temperatures, cold and warm receptors are unresponsive, but ____ _____ become active
thermal nociceptors
True or False: Thermal Nociceptors are excited by extremes in temperature while Mechanical Nociceptors are activated by intense pressure applied to skin (e.g pinch)
True
Both Meissner and Pacinian Corpuscle’s have layered capsule and rapid adaptation. However, the prior uses ____ as a modality while the latter uses ____
Touch; Vibration
Which of the following receptors have a thin capsule, slow adaptation, and utilize pressure as a modality?
A. Pacinian Corpuscle
B. Meissner Corpuscle
C. Ruffini Endings
D. Free Nerve Endings
E. Endings Arounds Hairs
F. Free Nerve Ending
C. Ruffini Endings
Which two non-encapsulated receptors utilize touch as their modality?
A. Pacinian Corpuscle / Meissner Corpuscle
B. Ruffini Endings / Free Nerve Endings
C. Endings Arounds Hairs / Merkel Endings
C. Endings Arounds Hairs (rapid) / Merkel Endings (slow)
True or False: Merkel endings, free nerve ending, and endings around hairs are non-encapsulated
True
Which of the following non-encapsulated receptors is involved in pain, temperature, itch, and touch?
A. Endings around hairs
B. Merkel Endings
C. Ruffini Endings
D. Free Nerve Endings
D. Free Nerve Endings
______: Area of skin that, when stimulated, activates a particular sensory neuron
Receptive Fields
Which mechanoreceptor has a small receptive field and relays information from discrete areas of the skin?
A. Meissner’s Corpuscle
B. Pacinian Corpuscle
C. Ruffini Endings
D. Free Nerve Endings
A. Meissner’s Corpuscle
Which mechanoreceptors have large receptive fields and relay information from large areas of skin?
A. Meissner’s Corpuscle
B. Pacinian Corpuscle
C. Ruffini Endings
D. Free Nerve Endings
B. Pacinian Corpuscle
True or False: Fine Touch sensibility is associated with MANY neurons that have LARGE receptive fields while
Crude Touch sensibility is associated with MANY neurons that have SMALLER receptive fields
False -
Fine Touch sensibility is associated with MANY neurons that have SMALL receptive fields
Crude Touch sensibility is associated with FEWER neurons that have LARGER receptive fields
- Given this, there’s more axons and neurons throughout the CNS for processing of fine touch sensibility
____: The precision with which we can locate the site of stimulation
Acuity
How does the size of the receptor fields and the receptor density affect acuity?
Larger receptive field = less acuity
Greater density = greater acuity
How does overlap of adjacent receptive fields and convergence of neuronal input affect acuity?
The greater the overlap of adjacent receptive fields = greater acuity
The greater the convergence = less acuity
______: the minimum distance by which two stimuli can be separated and still be perceived as two stimuli
Two point discrimination
Where can the most precise two point discrimination be found?
A. Skin of finger tips, lips, tongue
B. Skin of arm, trunk, leg
A. Skin of finger tips, lips, tongue
- there’s a high density of sensory receptors with small receptor fields there
Where can the LEAST precise two point discrimination be found?
A. Skin of finger tips, lips, tongue
B. Skin of arm, trunk, leg
B. Skin of arm, trunk, leg
____: Area of the body that a particular spinal cord segment innervates, through its spinal nerves
Dermatomes
Each dermatome overlaps with __ distinct dermatomes so that a particular spinal cord segment innervates a portion of ___ successive dermatomal areas
A. 3; 2
B. 2; 3
C. 1; 3
D. 2; 4
B. 2; 3
Why does a lesion of a SINGLE spinal nerve or dorsal root of a spinal nerve produce little to no obvious sensory loss?
Overlapping pattern of dermatomes
How many successive dorsal roots need to be severed (lesioned) in order to observe obvious sensory losses?
Three (3)
Which principle states that the larger the diameter of the axon, the faster the conduction velocity?
The Size Principle
Which three peripheral nerves are HIGHLY myelinated?
A. Ia; Ib; Aa
B. B; Ia; Aa
C. IV C; Ib; Ia
A. Ia; Ib; Aa
True or False: IV C are non-myelinated receptors
True
AB (II) receptors corresponds to ___ while AB (III) or C (IV) correspond to ____
Mechanoreceptors; Thermal receptors
Ia or II corresponds to _____
A. Mechanoreceptors
B. Golgi Tendon Organs
C. Nociceptors
D. Muscle spindles
D. Muscle spindles
Ib corresponds to:
A. Mechanoreceptors
B. Golgi Tendon Organs
C. Nociceptors
D. Muscle spindles
B. Golgi Tendon Organs
Muscle tension is the stimulus for which receptor? Muscle length is the stimulus for which receptor?
Muscle tension = Muscle spindles
Muscle length = Golgi tendon organs
Primary somatosensory afferents originate from cell bodies in the ______
A. DRG
B. VRG
C. White Matter
D. Gray Matter
A. DRG
Where do primary somatosensory afferents enter the spinal cord through?
Dorsal Root Entry Zone (Dorsolateral Sulcus)
True or False: The Lateral Dorsal Root Entry Zone is associated with axons with SMALLER diameters while Medial Dorsal Root Entry Zone is associated with axons with LARGER diameters (more heavily myelinated)
True
Which of the following is typically associated with pain, temp, crude touch, and visceral afferents?
A. Lateral Dorsal Root Entry Zone
B. Medial Dorsal Root Entry Zone
A. Lateral Dorsal Root Entry Zone
Which of the following is associated with transmission of HIGHLY DISCRIMINATIVE forms of touch and proprioception (skeletal muscles and joints)?
A. Lateral Dorsal Root Entry Zone
B. Medial Dorsal Root Entry Zone
B. Medial Dorsal Root Entry Zone
Which axons tend to decussate in somatosensory pathways?
A. First order
B. Second order
C. Third order
B. Second order
All of the ascending sensory pathways stop in the ___, except for olfaction
A. Cerebellum
B. Cerebral Cortex
C. Thalamus
D. Hypothalamus
C. Thalamus
Fibers ascending to the thalamus are usually organized in flat bundles called ____
lemnisci
Fibers leaving the thalamus radiate towards the cerebral cortex, passing through the _____ ____, forming thalamic radiations
internal capsule
Which system serves epicritic sensations (highly localizable, discriminative sensory, touch, proprioception, vibration, 2 point discrimination)?
A. Anterolateral System
B. Dorsal Column Medial Lemniscal System
B. Dorsal Column Medial Lemniscal System
Which three tracts make up the Anterolateral System?
- Spinothalamic tract
- Spinoreticulothalamic tract
- Spinotectal tract
True or False: The Anterolateral System carries protopathic and epicritic sensory information
True