Term
| what are the 2 major components of the somatosensory system |
|
Definition
| mechanosensory system, nociception system |
|
|
Term
| what does the mechanosensory system detect |
|
Definition
| mechanical stimuli: pressure, vibration, gentle touch, proprioception |
|
|
Term
| what are the 2 types of proprioception |
|
Definition
| conscious and unconscious |
|
|
Term
| what is conscious proprioception |
|
Definition
| when you close your eyes and put your hand out and you still know where your hand is |
|
|
Term
| what determines the size of a homonculous's body parts? |
|
Definition
| amount of sensory representation it has in the cortex |
|
|
Term
| what is unconscious proprioception |
|
Definition
| our knowledge of where our body is without really thinking about it |
|
|
Term
| what 2 things does the nociception system detect? |
|
Definition
|
|
Term
| what does the somatosensory system, the combination of the mechanosensory and nociception systems, do for us? |
|
Definition
| allow humans to identify objects, monitor forces acting on our bodies, and detect potentially harmful stimuli |
|
|
Term
| do the mechanosensory and nociception systems follow the same pathway to/from the brain? |
|
Definition
|
|
Term
| what initiates the mechanosensory processing of stimuli |
|
Definition
| activation of a diverse population of cutaneous mechanoreceptors at the body's surface |
|
|
Term
| what are the 4 kinds of mechanoreceptors |
|
Definition
| meissner's, pacinian, ruffini's, merkel's |
|
|
Term
| what kinds of mechanorceptors are found in muscles and joints |
|
Definition
|
|
Term
| briefly, what is a muscle spindle |
|
Definition
| specialized proprioceptor |
|
|
Term
| what do mechanoreceptors do |
|
Definition
| relay information to the CNS for interpretation and ultimately action |
|
|
Term
| where do we find meisner's, pacinian, ruffini's, merkel's receptors |
|
Definition
|
|
Term
| what are the 4 main types of receptors classified based on function |
|
Definition
| mechanoreceptors, proprioceptors, nociceptors, thermoreceptors |
|
|
Term
| what do proprioceptors detect? |
|
Definition
| mechanical forces on our muscles and joints |
|
|
Term
| what do nociceptors detect |
|
Definition
|
|
Term
| what do thermoreceptors detect |
|
Definition
|
|
Term
| what are the 2 types of receptors based on morphology |
|
Definition
| encapsulated receptors, free nerve endings |
|
|
Term
| what are encapsulated receptors |
|
Definition
| relatively large encapsulated receptors with myelinated axons specialized to detect mechanical stimuli |
|
|
Term
| what do we know about myelinated axons? |
|
Definition
| they're quick. They convey information that moves very, very fast. |
|
|
Term
| are free nerve endings myelinated |
|
Definition
| no OR they are lightly myelinated |
|
|
Term
| do free nerve endings or encapsulated receptors send signals more quickly |
|
Definition
|
|
Term
| what are free nerve endings |
|
Definition
| unmyelinated or lightly myelinated terminal brances of sensory neurons that play a major role in the detection of pain and temperature |
|
|
Term
| how do all sensory receptors work |
|
Definition
| stimuli applied to the skin affects the ionic permeability of the receptor membrane; changes in membrane permeability generate a receptor potential; receptor potential triggers an action potential in the sensory neuron; this action potential conveys sensory information toward the CNS |
|
|
Term
| what is sensory transduction |
|
Definition
| critical first step in all sensory processing: he overall process of the energy of the stimulus (finger touch, for example) converted into an electrical signal in the sensory neuron |
|
|
Term
| what happens if you poke a pacinian corpuscle |
|
Definition
| it changes the membrane permeability, ions pour in, starts an action potential that goes up to the CNS |
|
|
Term
| how does the mechanosensory information poject into the CNS? |
|
Definition
| by way of a 3 neuron system |
|
|
Term
| what are the 3 nerves in the 3 neuron system? |
|
Definition
| 1st order neuron, 2nd order neuron, 3rd order neuron |
|
|
Term
| where does the 1st order neuron go? |
|
Definition
| tip of your finger to spinal cord |
|
|
Term
| where does the 2nd order neuron go? |
|
Definition
|
|
Term
| where does the 3rd order neuron go? |
|
Definition
| thalamus to primary sensory cortex |
|
|
Term
| how does mechanosensory informatino from the body project to the brain |
|
Definition
|
|
Term
| what determines how much (quantity) we feel and what it's like (quality) |
|
Definition
| properties of individual receptors |
|
|
Term
| in what 2 ways do different receptors fire? |
|
Definition
| some receptors fire rapidly then adapt; other receptors generate a sustained train of action potentials |
|
|
Term
| what do slowly adapting mechanoreceptors do when stimulated |
|
Definition
|
|
Term
| what do rapidly adapting receptors do when stimulated |
|
Definition
| fire an action potential and then stop. When stimulation ends, they might fire again. |
|
|
Term
| what is another term for slowly adapting receptors |
|
Definition
|
|
Term
| what is another term for rapidly adapting receptors |
|
Definition
|
|
Term
| what information do tonic receptors convey |
|
Definition
| information about the persistence or static quality of stimuli |
|
|
Term
| what do phasic receptors give us the ability to do |
|
Definition
| ability to detect changes in stimuli |
|
|
Term
| what innervates all mechanoreceptors |
|
Definition
| large, myelinated type Abeta axons |
|
|
Term
| how does mechanosensory information get to the brain so quickly |
|
Definition
| large, myelinated type Abeta axons |
|
|
Term
| are all mechanoreceptors low or high threshold receptors |
|
Definition
|
|
Term
| what does it mean that mechanoreceptors are low threshold receptors |
|
Definition
| mild stimulation of skin evokes receptor potentials; their threshold is very close to their resting membrane potential to send an action potential |
|
|
Term
| what are the 4 low-threshold mechanoreceptors |
|
Definition
| meissner's, pacinian, ruffini's, merkel's |
|
|
Term
| describe the axons of meissner's corpuscles |
|
Definition
| one or more afferent axons |
|
|
Term
| do meissner's corpuscles have rapdly adapting or slowly adapting receptors |
|
Definition
| rapidly adapting receptors |
|
|
Term
| how many receptors in the hand are meissner's corpuscles |
|
Definition
|
|
Term
| what do meissner's corpuscles detect |
|
Definition
| low frequency vibrations and tactile discrimination (textured objects that move across the skin) |
|
|
Term
| what kind of receptors could feel the ridges on the side of a quarter |
|
Definition
|
|
Term
| describe the structure/axons of pacinian corpuscle |
|
Definition
| onion-like capsule surrounds one or more afferent axons |
|
|
Term
| do pacinian corpuscles have rapdly adapting or slowly adapting receptors |
|
Definition
| rapidly adapting receptors |
|
|
Term
| what do pacinian corpuscles detect in the skin |
|
Definition
| high frequency vibrations and deep pressure |
|
|
Term
| aside from skin, where else are pacinian corpuscles found |
|
Definition
|
|
Term
| what do pacinian corpuscles detect in interosseous membranes |
|
Definition
|
|
Term
| where are merkel's disks located |
|
Definition
|
|
Term
| how many receptors in the hand are merkel's disks |
|
Definition
|
|
Term
| are merkel's disks rapidly adapting or slowly adapting receptors |
|
Definition
| slowly-adapting receptors |
|
|
Term
| what do merkel's disks do |
|
Definition
| transmit light pressure sensations |
|
|
Term
| what do ruffini's corpuscles do |
|
Definition
| function as cutaneous stretch receptors during digital movement |
|
|
Term
| are ruffini's corpuscles rapidly adapting or slowly adapting receptors |
|
Definition
| slowly-adapting receptors |
|
|
Term
| how many receptors in the hand are ruffini's corpuscles |
|
Definition
|
|
Term
| what is mechanosensory discrimination |
|
Definition
| the accuracy with which tactile stimulation can be sensed varies from one region of the body to the next |
|
|
Term
| how can you assess a body part's mechanosensory discrimination |
|
Definition
|
|
Term
| what determines the variation of mechanosensory discrimination throughout the body? |
|
Definition
| the quantity of encapsulated receptors |
|
|
Term
| what is the receptive field of a neuron |
|
Definition
| the region of the skin within which a tactile stimulus evokes a sensory response in the neuron or its axon |
|
|
Term
| what is the size of the neuronal receptive field important for |
|
Definition
|
|
Term
| are the receptive fields of mechanosensory neurons in the hands or in the arms smaller |
|
Definition
|
|
Term
| what is the size of receptive fields of mechanosensory neurons in the fingertips |
|
Definition
|
|
Term
| what is the size of receptive fields of mechanosensory neurons in the palms |
|
Definition
|
|
Term
| what part of the receptive field must be touched to trigger an action potential in the sensory neuron |
|
Definition
|
|
Term
| what effect does touch in the surrounding or outside of the receptive field have on the sensory neuron |
|
Definition
|
|
Term
| what 2 things determine regional differences in mechanosensory discrimination |
|
Definition
| both the quantity (density) of the mechanoreceptors and the size of the neuronal receptive field determine regional differences in mechanosensory discrimination |
|
|
Term
|
Definition
| specialized receptors that provide information about the mechanical forces arising from the musculoskeletal system |
|
|
Term
| where are proprioceptors located |
|
Definition
|
|
Term
| what are the 3 types of proprioceptors |
|
Definition
| muscle spindles, golgi tendon organs, joint receptosr |
|
|
Term
|
Definition
| low threshold receptors in muscles specialized to signal changes in muscle length |
|
|
Term
| are proprioceptive receptors low threshold or high threshold |
|
Definition
|
|
Term
| what do muscle spindles respond to |
|
Definition
|
|
Term
| what do golti tendon organs respond to |
|
Definition
| changes in muscle tension |
|
|
Term
| what do joint receptors send information about |
|
Definition
| limb position and joint movement |
|
|
Term
| what are golgi tendon organs |
|
Definition
| low threshold receptors in tendons specialized to signal changes in muscle tension |
|
|
Term
|
Definition
| low threshold and rapidly adapting receptors in joints that signal information about limb position and joint movement |
|
|
Term
| what do joint receptors tell you |
|
Definition
| if your joint is flexed/extended and by how much |
|
|
Term
| where are muscle spindles found |
|
Definition
|
|
Term
| what do muscle spindles consist of |
|
Definition
| 4-8 specialized intrafusal muscle fibers surrounded by a capsule |
|
|
Term
|
Definition
|
|
Term
| what does it mean if a fiber is intrafusual |
|
Definition
| the fiber is surrounded by a capusle |
|
|
Term
| what is the largest intrafusal fiber |
|
Definition
|
|
Term
| where are the nuclei in the nuclear bag fiber |
|
Definition
| the nuclei are collected in the center region of the muscle spindle |
|
|
Term
| are the muscle fibers with sarcomeres that we've studided before intrafusal or extrafusal |
|
Definition
|
|
Term
| are muscle spindles big enough to see with the naked eye |
|
Definition
|
|
Term
| what are the remaining intrafusal fibers (besides the nuclear bag fiber) called? |
|
Definition
|
|
Term
| describe the nuclei of a nuclear chain fiber |
|
Definition
| the nuclei are lined up in single file |
|
|
Term
| what type of axons convey the sensory/proprioception information that comes from the muscle spindles |
|
Definition
|
|
Term
| are group 1a sensory axons myelinated? |
|
Definition
|
|
Term
| are group 1a sensory axons large? |
|
Definition
|
|
Term
| does sensory information travel quickly on group 1a axons? |
|
Definition
|
|
Term
| describe the physical connection between the group 1a sensory axons and the intrafusal fibers |
|
Definition
| the sensory axons encircle and innervate the intrafusal fibers |
|
|
Term
| do the sensory axons encircle the nuclear bag fiber, the nuclear chain fibers, or both |
|
Definition
|
|
Term
| what is the Primary Sensory Ending of the muscle spindle |
|
Definition
| where the sensory axons encircle the intrafusal fibers |
|
|
Term
| what is secondary innervatino of the muscle spindle |
|
Definition
| innervation by group II axons that innervate nuclear chain fibers and give off minor branches to nuclear bag fibes |
|
|
Term
| what type of neurons innervate the intrafusal fibers to cause the spindle to contract |
|
Definition
|
|
Term
| are group 2 axons as big/fast as group 1a fibers? |
|
Definition
| no, but they're still pretty fast |
|
|
Term
| are gamma motor neurons or alpha motor neurons smaller |
|
Definition
| gamma motor neurons are smaller than alpha motor neurons |
|
|
Term
| what id the function of muscle spindles |
|
Definition
| provide information to the CNS about muscle length |
|
|
Term
| do large muscles have low or high density of spindles |
|
Definition
|
|
Term
| do muscles that perform demanding tasks have low or high density of spindles |
|
Definition
|
|
Term
| how does mechanosensory information project into the CNS |
|
Definition
| by way of a 3 neuron system |
|
|
Term
| to what side of the brain does information from the left side of my body project |
|
Definition
|
|
Term
| what is the first order neuron |
|
Definition
| the neuron connected to the receptor |
|
|
Term
| what is the dorsal column-medial lemniscus system |
|
Definition
| the 3 neuron system that relays mechanosensory stimuli from the arms, legs, and trunk |
|
|
Term
| why is it called the dorsal column medial lemniscus system |
|
Definition
| because it travels up the dorsal column |
|
|
Term
| what is the primary function of the dorsal column medial lemniscus |
|
Definition
| to convey discriminative touch and conscious proprioception information to the sensory cortex |
|
|
Term
| where are 1st order neuron cell bodies located |
|
Definition
|
|
Term
| describe the peripheral processes of the 1st order neurons |
|
Definition
| long; end in cutaneous receptors |
|
|
Term
| describe the centrally projecting axons of the 1st order neurons |
|
Definition
| short; enter the dorsal horn of the spinal cord via the dorsal root |
|
|
Term
| do 1st order neurons ascend ipsilaterally up the dorsal column, or do they cross? |
|
Definition
| 1st order neurons travel ipsilaterally up the dorsal column |
|
|
Term
| through what tracts in the dorsal column do 1st order neurons travel |
|
Definition
| gracile and cuneate tracts |
|
|
Term
| where do 1st order neurons synapse on 2nd order neurons |
|
Definition
| lower medulla: gracile or cuneate nuclei |
|
|
Term
| when does a 1st order neuron synapse with a 2nd order neuron in the gracile nucleus? |
|
Definition
| when the mechanosensory information comes from the lower body |
|
|
Term
| when does a 1st order neuron synapse with a 2nd order neuron in the cuneate nucleus |
|
Definition
| when the mechanosensory information comes from the upper body |
|
|
Term
| what do the 2nd order neurons do once the 1st order neurons have synapsed with them in the medulla |
|
Definition
| 2nd order neurons cross the midline of the medulla and form the medial lemniscus |
|
|
Term
| what is the decussation fo the medial lemniscus |
|
Definition
| the crossing of the the fibers of the 2nd order neuron |
|
|
Term
| where do the 2nd order neurons ascending the medial lemniscus go? |
|
Definition
| to the ventral posterior lateral nucleus of the thalamus |
|
|
Term
| what happens at the VPL of the thalamus |
|
Definition
| 2nd order neurons synapse on the 3rd order neurons |
|
|
Term
| after the 2nd order neurons synapse on the 3rd order neurons in the VPL, what do the 3rd order neurons do? |
|
Definition
| they then project via the internal capsule to cortical neurons in the primary somatic sensory cortex |
|
|
Term
| what does the 3rd order neuron travel through to get to cortical neurons in the primary somatic sensory cortex |
|
Definition
|
|
Term
| what is the somatotropic order of the primary somatic sensory cortex |
|
Definition
| body parts from toes to face are represented medial to lateral |
|
|
Term
| does info from the lower body go to the medial or lateral primary somatic sensory cortex? |
|
Definition
|
|
Term
| does info from the uppper body go to the medial or lateral primary somatic sensory cortex? |
|
Definition
|
|
Term
| what part of your body do you lose sensory information to if you get a stroke of your anterior cerebral artery |
|
Definition
|
|
Term
| what pathway carries mechanosensory information from the face to the CNS |
|
Definition
| trigeminal lemniscus system |
|
|
Term
| what 3 distributions of the trigeminal nerve provide sensation to the face |
|
Definition
| ophthalmic, maxillary, mandibular |
|
|
Term
| what is another term for the ophthalmic division |
|
Definition
|
|
Term
| what is another term for the maxillary division |
|
Definition
|
|
Term
| what is another term for the mandibular division |
|
Definition
|
|
Term
| where does the ophthalmic division provide sensation |
|
Definition
| frontal bone region: between eyes and forehead |
|
|
Term
| where does the maxillary division provide sensation |
|
Definition
| maxillary bone region: between eyes and mouth |
|
|
Term
| where does the mandibular division provide sensation |
|
Definition
|
|
Term
| where do the sensory nerves of the trigeminal complex originate |
|
Definition
|
|
Term
| what are the 3 components of the trigeminal complex |
|
Definition
| principle sensory nucleus, spinal nucleus, mesencephalic nucleus |
|
|
Term
| what is the principle sensory nucleus responsible for |
|
Definition
| processing mechanosensory information |
|
|
Term
| where in the rbain is the principle sensory nucleus located |
|
Definition
|
|
Term
| what is the spinal nucleus responsible for |
|
Definition
| processing pain and temperature information |
|
|
Term
| where is the spinal nucleus located |
|
Definition
|
|
Term
| what is the trigeminal lemniscus pathway |
|
Definition
| 3 neuron pathway that conveys mechanosensory stimuli from the face to the CNS |
|
|
Term
| where are the cell bodies of the 1st order neuron in the trigeminal lemniscus pathway located |
|
Definition
|
|
Term
| where do the peripheral processes (V1, V2, V3) of the first order neurons of the trigeminal lemniscus end |
|
Definition
|
|
Term
| where do the central processes of the 1st order neurons of the trigeminal lemniscus end and what do they do there |
|
Definition
| synapse on 2nd order neurons in the principal sensory nucleus of trigeminal |
|
|
Term
| what do 2nd order neurons of the trigeminal lemniscus do after they are synapsed on by the 1st order neuron central prcesses |
|
Definition
| send their axons across the midline of the pons and ascend toward the thalamus |
|
|
Term
| which order neurons cross in the trigeminal lemniscus |
|
Definition
|
|
Term
| where do the 2nd order neurons corss in the trigeminal lemniscus |
|
Definition
|
|
Term
| what do 2nd order neurons of the trigeminal lemniscus do after crossing the pons |
|
Definition
| ascend in the trigeminal lemniscus pathway |
|
|
Term
| what is the destination of 2nd order neurons as the ascend the trigeminal lemniscus pathway |
|
Definition
| ventral posterior medial nucleus of the thalamus |
|
|
Term
| where do 2nd and 3rd order neurons synapse in the trigeminal lemniscus |
|
Definition
| VPM nucleus of the thalamus |
|
|
Term
| what do 3rd order neurons of the trigeminal lemniscus do after they are synapsed on by the 2nd order neurons |
|
Definition
| ascend to the primary somatic sensory cortex via the internal capsule |
|
|
Term
| where does the 2nd order neuron of the dorsal column medial lemniscus cross |
|
Definition
|
|
Term
| if you have a stroke in the pons, is that more likely to affect sensory from face or sensory from body |
|
Definition
|
|
Term
| what does it mean that the axon fibers from mechanosensory systems decussate |
|
Definition
| they cross in the brainstem |
|
|
Term
| what sensory components pass through the thalamus |
|
Definition
| all senses except for olfaction |
|
|
Term
| what are the 2 parts of the ventral posterior complex of the thalamus |
|
Definition
| ventral posterior lateral, ventral posterior medial |
|
|
Term
| why are the ventral posterior complexes important |
|
Definition
| they are the main target of ascending sensory pathways |
|
|
Term
| from what mechanosensory pathway does the VPL nucleus receive projections |
|
Definition
| dorsal column medial lemniscus |
|
|
Term
| where does the somatosensory information come from that reaches the VPL |
|
Definition
|
|
Term
| from what pathway does the VPM nucleus receive projections |
|
Definition
|
|
Term
| where does the somatosensory information come from that reaches the VPM |
|
Definition
|
|
Term
| when somatic sensory axons first leave the thalamus, where do they go |
|
Definition
| they project to cortical neurons in layer IV of the somatosensory complex |
|
|
Term
| where is sensory information from the somatosensory complex ultimately relayed |
|
Definition
| many regions of the brain including frontal, parietal, temporal, and limbic lobes |
|
|
Term
| what is the somatic sensory cortex usually called |
|
Definition
| primary somatic sensory cortex, SI |
|
|
Term
| where in the brain is the primary somatic sensory cortex located |
|
Definition
| postcentral gyrus, parietal lobe |
|
|
Term
| what are the 4 Brodmann's areas of the primary somatic sensory cortex |
|
Definition
|
|
Term
| which of the Brodmann's areas of the primary somatic sensory cortex is the main sensory cortex |
|
Definition
|
|
Term
| what does each Brodmann's area in the primary somatic sensory cortex contain |
|
Definition
| a unique and complete representation of the body - somatotopic map |
|
|
Term
| what do neurons in Brodmann's area 3a respond mainly to |
|
Definition
| muscle stretch receptors = proprioception |
|
|
Term
| what do neurons in Brodmann's area 3b respond mainly to |
|
Definition
| tactile cutaneous receptors |
|
|
Term
| what do neurons in Brodmann's area 1 respond mainly to |
|
Definition
|
|
Term
| what do neurons in Brodmann's area 2 respond mainly to |
|
Definition
|
|
Term
| from where do Brodmann's areas 1 and 2 get their information |
|
Definition
|
|
Term
| are different areas of the primary somatic sensory cortex responsible to different or the same aspects of sensation |
|
Definition
|
|
Term
| what 2 broad criteria operate in the organization of the somatic sensory system |
|
Definition
|
|
Term
| what does the somatosensory system do with the information of modality and somatotopy |
|
Definition
| integrates and projects this information to many regions of the brain |
|
|
Term
| what is the result in the primary somatic sensory cortex's integration and projection of information of modality and somatotopy to many regions of the brain |
|
Definition
| results in a unified perceptual representation of the body with the environment |
|
|
Term
| term used to describe the cortical and subcortical fields that receive somatic sensory information from the primary sensory cortex? |
|
Definition
|
|
Term
|
Definition
| secondary somatosensory cortex |
|
|
Term
| from where does SII receive projections |
|
Definition
|
|
Term
| to where does SII send projections |
|
Definition
|
|
Term
| what is the higher order pathway of SII important for |
|
Definition
| tactile learning, memory, and the emotional component of sensory information |
|
|
Term
| besides SII, where else does SI distribute incoming sensory information to |
|
Definition
| motor cortex (area 4) and other associational cortices (5&7) |
|
|
Term
| what is the parietal lobe important for |
|
Definition
|
|
Term
| are there more descending or ascending sensory pathways from the somatosensory cortex? |
|
Definition
|
|
Term
| where do descending projections from the somatosensory cortex go |
|
Definition
| thalamus, brainstem, spinal cord |
|
|
Term
| what do the descending projectinos from the somatosensory cortex do |
|
Definition
| modulate the flow of ascending sensory information |
|
|
Term
|
Definition
| the sensory innervation arising from a single dorsal root ganglion and its spinal nerve or spinal cord level |
|
|
Term
|
Definition
|
|
Term
| does injury to an individual dorsal root always result in complete loss of sensation to the relevant skin region |
|
Definition
|
|
Term
| is the overlap in dermatomes more extensive for touch/pressure or for pain/temp |
|
Definition
| more extensive for touch/pressure. |
|
|
Term
| doees pain or touch provide a more accurate assessment of segmental nerve injury |
|
Definition
|
|
Term
| dermatome for nipple level |
|
Definition
|
|
Term
| dermatome for belly button |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
