Sensory Systems

Front 1

Which pain fibers conduct first and second pain?

Back 1

First is fast fibers- A-delta Second is slow fibers- C

Front 2

which receptor responds to cold?

heat?

menthol?

Back 2

Front 3

what's the inflammatory soup?

Back 3

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.

Front 4

can nocioceptors be desensitized?

Back 4

Front 5

Afferents Enter the Dorsal Horn and Move Up and Down

Back 5

Lissauer’s Tract

Front 6

Primary Afferents Synapse in the _____

Back 6

the compartments are rexed laminae

Front 7

“The Rexed laminae comprise a system of ten layers of grey matter (I-X),

Back 7

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

Front 8

substantia gelatinosa is rexed lamina ___

composed of _____

Back 8

interneurons

Front 9

convergence of lamina ___ produces referred pain

Back 9

Lamina V: wide-dynamic-range neurons project to brain stem and thalamus. Ab, Ad, and C from viscera; either direct or via interneurons

Front 10

Back 10

referred pain

Front 11

Spinothalamic tract – crossed fibers, nociceptive-specific and wide-dynamic range neurons from Laminae I & V-VII. Project to ___

Back 11

thalamus

Front 12

spinothalamic tract

Back 12

Front 13

how many nuclei of trigeminal? what are they? where are they located?

Back 13

Front 14

tell me how P/T fibers of the head join with P/T fibers of the rest of the body....

Back 14

Front 15

where do fibers of the ST tract go to?

Back 15

VPL ...ventral posterior lateral nucleus

of the thalamus

Front 16

where is P/T processed in the cortex?

Back 16

Front 17

where is P/T processed in the cortex?

Back 17

Front 18

which system in involved in the emotional part of pain?

Back 18

the limbic system!

Front 19

Back 19

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.

Front 20

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

Back 20

true!

1. Convergent input into Lamina V from C/Ad fibersas 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 inhibitLamina II interneurons

Front 21

PAG (periaqueductal gray) stimulation specificallyinhibits ____
(Lamina V neurons).

Back 21

nocioception

Front 22

name endogenous, exogenous

agonists/antagonists of opiod receptors?

Back 22

Front 23

mechanism of opiod analgesia?

Back 23

Front 24

draw a chart:
all the touch receptors, whether deep/superficial, their receptor field size, adaptation

Back 24

Front 25

draw a chart:
all the touch receptors, whether deep/superficial, their receptor field size, adaptation

Back 25

Front 26

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.

Back 26

graded

action potentials

action potentials

Front 27

All sensory pathways pass through the thalamus except for _____. 

Back 27

olfaction

Front 28

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.

Back 28

neurons

olfactory bulb


prepiriform cortex

Front 29

C fibers (slow pain) are the ____nerve fibers and therefore have the slowest conduction velocity.

Back 29

smallest

(more resistance...remember that conduction speed dependent on capacitance (myelination or not) and fiber diameter)

Front 30

___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.

Back 30

CN1
C fibers

trigeminal

Front 31

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.

Back 31

raphe nuclei

Front 32

Brodman Areas to Know

17 –
41/42 –
1/2/3 –
4 –

Back 32

17 – 1° Visual Cx
41/42 – Auditory Cx
1/2/3 – Somatosensory
4 – Primary Motor Cx