Term
| 2 classifications of dorsal root fibers conducting from somatosensory receptors according to conduction velocity |
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Definition
1. myelinated A fibers
2. myelinated C fibers |
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Term
| Do all primary sensory neurons release a classical neurotransmitter with fast synaptic actions in the spinal cord? |
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Definition
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Term
| Substance P is an example of what kind of molecule found in many primary sensory neurons? |
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Definition
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Term
| The ventral branches of the spinal nerves form _____ supplying the arms & the legs |
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Definition
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Term
| Is the segmental origin of the fibers retained in the peripheral distribution of the fibers? |
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Definition
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Term
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Definition
| the area of the skin supplied with sensory fibers from one spinal segment |
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Term
| 5 basic modalities of sensory experiences that can be evoked from the skin (although there are almost indefinite amounts) |
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Definition
1. touch
2. pressure
3. heat
4. cold
5. pain |
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Term
| 3 classifications of skin receptors based on their adequate stimulus |
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Definition
1. mechanoreceptors
2. thermoreceptors
3. chemoreceptors |
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Term
| _____ cover the axonal ramifications of the free receptors, except at their tips, where their receptor properties presumably reside |
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Definition
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Term
| What type of receptor is associated with nociception in the skin (or wherever painful sensations can be evoked) |
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Definition
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Term
| high-threshold mechanoreceptor |
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Definition
| a type of receptor that responds to intense mechanical stimulation only |
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Term
| Can receptors be activated by multiple types of sensation (ex. mechanical stimuli, warming of the skin, & chemical substances liberated by tissue damage/inflammation)? |
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Definition
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Term
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Definition
| receptors that can be activated by different sensory modalities |
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Term
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Definition
| receptors that are unresponsive to most nociceptive stimuli used in animal experiments |
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Term
| How does ATP excite nociceptors? |
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Definition
| it binds to purinoceptors |
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Term
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Definition
| the peptide that is produced by the release of proteolytic enzymes from damaged cells & acts on specific membrane receptors in nociceptors |
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Term
| How are H+ ions related to nociceptors? |
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Definition
| they activate nociceptors effectively & seem to increase their responses to inflammatory substances |
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Term
| Are nociceptors sensitized or desensitized by prolonged stimulation? |
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Definition
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Term
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Definition
| a condition of abnormal intensity of pain compared to the strength of the stimulus |
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Term
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Definition
| when innocuous stimuli (such as a light touch) evoke intense pain |
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Term
| What system's activity is modulated by signals from silent nociceptors? |
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Definition
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Term
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Definition
| low-threshold mechanoreceptors that are slowly adapting |
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Term
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Definition
| a slowly adapting, low-threshold mechanoreceptor that is present particularly on the distal parts of the extremities, the lips, & the external genitals |
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Term
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Definition
| a type of low-threshold mechanoreceptor that is found at the junction between the dermis & the subcutaneous layer (also present in the mesenteries, vessel walls, joint capsules, & periosteum) |
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Term
| Are Pacinian corpuscles rapidly or slowly adapting? |
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Definition
| very rapidly adapting; elicit only one or two action potentials in the afferent fiber at the onset of indentation of the skin |
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Term
| What does the size of the receptive field depend on? |
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Definition
| the area of the skin receiving axonal branches from the sensory neuron |
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Term
| In general, where is the density of sensory units (the number of units innervating a given section of the skin) the highest? (it is also where receptive fields are smaller) |
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Definition
| in distal parts of the body |
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Term
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Definition
| the smallest distance at which two stimuli can be discriminated |
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Term
| Does lateral inhibition occur at all levels of the sensory pathways & in all sensory systems? |
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Definition
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Term
| differences between group I, group II, and group III muscle afferents |
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Definition
group I: fast conducting, thick myelinated fibers
group II: medium-sized myelinated fibers
group III: thinnest myelinated fibers |
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Term
| group IV muscle afferents |
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Definition
| slowly conducting unmyelinated fibers |
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Term
| difference between Ia & Ib muscle afferent fibers (subtypes of group I) |
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Definition
| Ib fibers conduct slightly more slowly than Ia fibers |
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Term
| Are there sensory units in human muscle that have nociceptor-like properties? |
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Definition
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Term
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Definition
| when stimulation continues or its intensity is increased & the pain radiates to other regions than the muscle itself |
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Term
| Are intrafusal fibers (fibers of the muscle spindle) larger/thicker or shorter/thinner than ordinary extrafusal muscle fibers? |
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Definition
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Term
| How are nuclei distributed in the nuclear chain fiber? |
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Definition
| evenly along the muscle fiber |
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Term
| What do group Ia & group II fibers inform the CNS about the muscle? |
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Definition
| the length of the muscle (because the riding rate of these groups depends on the length of the muscle) |
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Term
| How many types of gamma motoneurons exist? |
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Definition
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Term
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Definition
| the type of gamma motoneurons that increases the dynamic sensitivity of the muscle spindle |
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Term
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Definition
| the type of gamma motoneurons that increase the static sensitivity of the muscle spindle |
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Term
| What type of receptor is a Golgi tendon organ (tendon organ)? |
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Definition
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Term
| Is the tendon organ more sensitive to the tension produced by active contraction or produced by passive stretch? |
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Definition
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Term
| How many groups of low-threshold mechanoreceptor encapsulated joint receptors are there? |
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Definition
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Term
| What does the type 1 joint receptor resemble? |
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Definition
| the Ruffini corpuscle in the dermis |
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Term
| What does the type 2 joint receptor resemble? How is it different? |
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Definition
| the Pacinian corpuscle; it is considerably smaller than the corpuscle |
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Term
| What do type 2 joint receptors signal? |
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Definition
| movement velocity (hence, they are also called acceleration receptors) |
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Term
| What does the type 3 encapsulated receptor resemble? Where is it present? |
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Definition
| the tendon organ; only in the ligaments |
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Term
| 3 things contained in the joint capsules & ligaments |
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Definition
1. high-threshold mechanoreceptors
2. poly-modal nociceptors
3. "silent" nociceptors |
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Term
| Release of _____ is believed to have a role in the development of inflammatory arthritis in humans |
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Definition
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Term
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Definition
| the type of free joint receptors that play a part in circulatory & respiratory reflexes that are elicited by passive joint movements |
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Term
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Definition
| the perception of joint position, joint movement, & the direction/velocity of joint movements |
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Term
| 3 structures that contribute to kinesthesia |
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Definition
1. muscle spindles
2. joint receptors
3. skin receptors |
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Term
| Where do muscle spindles contribute most to kinesthesia? What about joint/skin receptors? |
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Definition
muscle: large joints (ex. hip & knee)
receptors: finger & toe |
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Term
| Where do the sensory fibers of the spinal nerves have their cell bodies? |
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Definition
| in the dorsal root ganglia |
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Term
| 2 branches that the central process divides into after entering the cord |
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Definition
1. ascending
2. descending |
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Term
| difference between group A & group C fibers |
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Definition
group A: myelinated
group C: unmyelinated |
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Term
| difference between A alpha, A beta, & A delta fibers within the A group |
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Definition
A alpha: fastest conducting
A beta: somewhat slower conducting
A delta: thinnest of the myelinated fibers |
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Term
| What type of fibers conduct low-threshold mechanoreceptor signals? Cold receptor signals? Heat receptors? |
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Definition
mechanoreceptor: thick myelinated
cold: thin myelinated
heat: unmyelinated |
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Term
| 2 types of fibers that conduct signals from nociceptors |
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Definition
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Term
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Definition
1. fast pain (experienced immediately after the stimulus, well localized, not very intense)
2. slow pain (occurs with a longer latency, more unpleasant, not well localized, continues after the end of the stimulus) |
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Term
| Which fibers are blocked last by the injection of local anesthetics around a peripheral nerve? Which are blocked first? |
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Definition
last: thickest myelinated
first: thinnest |
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Term
| What is the result of dermatomes overlapping? |
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Definition
| each spot on the skin is innervated by sensory fibers from at least two dorsal roots |
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