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32 Cards in this Set
- Front
- Back
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Which pain fibers conduct first and second pain?
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First is fast fibers- A-delta Second is slow fibers- C
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which receptor responds to cold?
heat? menthol? |
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what's the inflammatory soup?
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The molecular complexity of the primary afferent nociceptor is illustrated by its response to inflammatory mediators released at the site of tissue injury. Some of the main components of the 'inflammatory soup' are shown, including peptides (bradykinin), lipids (prostaglandins), neurotransmitters (serotonin (5-HT) and ATP) and neurotrophins (NGF). The acidic nature of the inflammatory soup is also indicated. Each of these factors sensitize (lower the threshold) or excite the terminals of the nociceptor by interacting with cell-surface receptors expressed by these neurons. Examples of these factors and representative molecular targets are indicated in the box. Activation of the nociceptor not only transmits afferent messages to the spinal cord dorsal horn (and from there to the brain), but also initiates the process of neurogenic inflammation. This is an efferent function of the nociceptor whereby release of neurotransmitters, notably substance P and calcitonin gene related peptide (CGRP), from the peripheral terminal induces vasodilation and plasma extravasation (leakage of proteins and fluid from postcapillary venules), as well as activation of many non-neuronal cells, including mast cells and neutrophils. These cells in turn contribute additional elements to the inflammatory soup.
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can nocioceptors be desensitized?
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Afferents Enter the Dorsal Horn and Move Up and Down
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Lissauer’s Tract
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Primary Afferents Synapse in the _____
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the compartments are rexed laminae
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“The Rexed laminae comprise a system of ten layers of grey matter (I-X),
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Marginal zone (Lamina I) – nociceptive-specific neurons & wide-dynamic-range neurons
Substantia gelatinosa (Lamina II) – interneurons Lamina IV Non-nociceptive neurons to (Ab fibers, Topographic organization) Lamina V: wide-dynamic-range neurons project to brain stem and thalamus. Ab, Ad, and C from viscera; either direct or via interneurons Lamina VI: non-noxious proprioceptive input. Lamina VII&VIII (in ventral horn): polysynaptic, some bilateral, VII has diffuse projections to reticular formation in brain stem => “diffuse” pain |
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substantia gelatinosa is rexed lamina ___
composed of _____ |
interneurons
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convergence of lamina ___ produces referred pain
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Lamina V: wide-dynamic-range neurons project to brain stem and thalamus. Ab, Ad, and C from viscera; either direct or via interneurons
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referred pain
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Spinothalamic tract – crossed fibers, nociceptive-specific and wide-dynamic range neurons from Laminae I & V-VII. Project to ___
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thalamus
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spinothalamic tract
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how many nuclei of trigeminal? what are they? where are they located?
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tell me how P/T fibers of the head join with P/T fibers of the rest of the body....
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where do fibers of the ST tract go to?
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VPL ...ventral posterior lateral nucleus
of the thalamus |
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where is P/T processed in the cortex?
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where is P/T processed in the cortex?
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which system in involved in the emotional part of pain?
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the limbic system!
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The descending systems that modulate the transmission of ascending pain signals. These modulatory systems originate in the somatic sensory cortex, the hypothalamus, the periaqueductal gray matter of the midbrain, the raphe nuclei, and other nuclei of the rostral ventral medulla. Complex modulatory effects occur at each of these sites, as well as in the dorsal horn.
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t/f
activation of nerves that do not transmit pain signals can interfere with signals from pain fibers and inhibit an individual's perception of pain |
true!
1. Convergent input into Lamina V from C/Ad fibers as well as touch/proprioceptive fibers (Ab) 2) Ab fibers inhibit neurons in Lamina V through interneurons 3) C/Ad fibers activate neurons in Lamina V, but inhibit Lamina II interneurons |
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PAG (periaqueductal gray) stimulation specifically inhibits ____
(Lamina V neurons). |
nocioception
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name endogenous, exogenous
agonists/antagonists of opiod receptors? |
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mechanism of opiod analgesia?
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draw a chart:
all the touch receptors, whether deep/superficial, their receptor field size, adaptation |
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draw a chart:
all the touch receptors, whether deep/superficial, their receptor field size, adaptation |
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Sensory receptor potentials are ____ potentials that may bring the membrane potential of the receptor cell either toward (depolarizing) or away from (hyperpolarizing) threshold. Receptor potentials are not ____, although ____ (which are all-or-none) may result if the membrane potential reaches threshold.
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graded
action potentials action potentials |
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All sensory pathways pass through the thalamus except for _____.
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olfaction
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Receptor cells in the olfactory pathway are true ____ whose axons form CN I, the olfactory nerve. These neurons project to mitral cells in the _____, which then projects to the _____ via the olfactory tract.
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neurons
olfactory bulb prepiriform cortex |
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C fibers (slow pain) are the ____nerve fibers and therefore have the slowest conduction velocity.
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smallest
(more resistance...remember that conduction speed dependent on capacitance (myelination or not) and fiber diameter) |
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___innervates the olfactory epithelium. Its axons are____Fracture of the cribriform plate can tear the delicate nerves and thereby eliminate the sense of smell (anosmia) – and a large part of the sense of taste.
However, the ability to detect ammonia is left intact because that is mediated through the ___nerve. Olfactory receptor cells are unique in that they are true neurons that are continuously replaced from undifferentiated stem cells. |
CN1
C fibers trigeminal |
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The _____ are a cluster of nuclei found in the brain stem. Their main function is to release serotonin to the rest of the brain. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets.
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raphe nuclei
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Brodman Areas to Know
17 – 41/42 – 1/2/3 – 4 – |
17 – 1° Visual Cx
41/42 – Auditory Cx 1/2/3 – Somatosensory 4 – Primary Motor Cx |
