Neuropathways (josh's take) Flashcards
Josh's guide to straight badassery of any and all neuropathways!!!!!
what are the layers of a nerve form outer to inner
Epineurium perineurium endoneurium
Lable this


Efferant pain signals travel where? and what does it control?
to extremities
motor and autonomic
Afferent pain singnals travel where? and what does it control
to the core (body)
pain and sensations
If you see these small dots what are you seeing?

individual fasicles
What fibers encompass the Afferent fibers?
A, B, & C
With afferent nerve fibers:
which nerve fibers are mylinated?
A and B
With afferent nerve fibers:
A nerve fibers are further defines as what subunits?
Alpha
Beta
Gamma
Delta
With afferent nerve fibers:
Which A fibers are fast, sharp well localized sensation?
delta!!!
With afferent nerve fibers:
so what are the characteristics of A-delta fibers again????
fast
sharp
well-localized sensation
(just making sure your getting it an dnot just going through the cards)
With afferent nerve fibers:
what nerve fiber is nonmylinated
C-fibers
With afferent nerve fibers:
which nerve fiber is slow and poorly localized?
C-fibers
With afferent nerve fibers:
what are the characteristics of C-fibers
slow, poorly localized
(just double checking again)
With afferent nerve fibers:
which 2 neve fibers are most discussed with regional? then quickly differentiate the 2!
A-fast, shape well localized
C- long, annoying lingering pain
With afferent nerve fibers:
the classification of the nerves (A B C) are based on what 2 things?
- Diameter
- Velocity
Must know this next chart forward and backwards!!! don’t memorize conduction speed just know which ones are faster and slower! for example if he askes which is faster A or B know it. After looking at the chart questions will follow!!

Must know:
4 sub units of type A fibers?
- alpha
- beta
- gamma
- delta
Must know:
Type A Alpha
- Function
- Diameter (µm)
- Myelin
- Conduction velocity (m/s) (for extra credit)
- proprioception, motor
- 15
- heavy
- 100
Must know:
Type A Beta
- Function
- Diameter (µm)
- Myelin
- Conduction velocity (m/s) (for extra credit)
- touch pressure
- 10
- heavy
- 50
Must know:
Type A Gamma
- Function
- Diameter (µm)
- Myelin
- Conduction velocity (m/s) (for extra credit)
- Muscle spindles
- 5
- heavy
- 25
Must know:
Type A Delta
- Function
- Diameter (µm)
- Myelin
- Conduction velocity (m/s) (for extra credit)
- pain (sharp); temp
- <5
- heavy
- 25
Must know:
Type A (tricks to remember all facts)
- list them in order
- function gets more basic goiing down list
- diameter gets smaller going down list start with 15 then -5
- all highly myelinated
- conduction speed gets smaller start with 100 half till 25 then keep it there!
- Alpha/ beta/ gamma/ Delta
- Proprioception motor/ touch pressure/ muscle spindles/ pain temp
- 15/ 10/ 5 / <5
- all mylinated
- 100/ 50/ 25/ 25
Must know:
Type B nerve fibers
- Function
- diameter (µm)
- Mylelin
- Conduction velocity (bonus)
- preganglionic autonomic
- < 3
- light
- 10
****how to remmebr*** just like in the type A still getting smaller. diameter is smaller thus less mylelination thus less speed
Must know:
Type C:
2 types?
Dorsal horn
sympathetic
Must know:
Type C:
Dorsal
- function
- Diameter
- Myelin
- Conduction (bonus)
- pain (dull) temp
- 1
- none
- 1
Must know:
Type C:
Sympathetic
- function
- diameter
- myelin
- conduction
- postganglionic
- 1
- none
- >1
what is transduction?
noxiuos stimuli translated into electrical activity at the sensory endings of nerves
what is TRANSMISSION?
propagation of impulses throughout the sensory nervous system (process of signal going up arm to brain
What is modulation?
Efferent control of pain (what my body does with the pain)
with the afferent pathway the whole processes is essentially what?
Transmission
FIRST ORDER NEURONS:
are neurons _____ _____ the spinal cord?
comming into
FIRST ORDER NEURONS:
The majority enter the ______ spinal root.
dorsal
FIRST ORDER NEURONS:
the majority of first order neurons enter the dorsal spinal root at each _____, ______, ______ and ______ level?
cervical
thoracic
lumbar
sacral
FIRST ORDER NEURONS:
pain fibers originating in the head are carried by the ___1___, ___2___, __3___, and ___4___ nerves.
give name and number
- trigeminal (V)
- facial (VII)
- glossopharyngeal (IX)
- vagal (X)
FIRST ORDER NEURONS:
each first order nerve have specific ganglion whoch hold cell bodies of these nerves. the first order neurons in the ganglia reach the spinal cord and synapse with the _____________.
2nd order neuron
so once the 1st order neuron reached the spinal cord they become what?
2nd order neurons
SECOND ORDER NEURONS:
is made up of spinal cord gray matter divided into what
10 lamina
SECOND ORDER NEURONS:
what lamina relate to the dorsal horn?
I-VI
Afferent
SECOND ORDER NEURONS:
what 2 functions do the I-VI lamina of the dorsal horn have
- receives all afferent neural activity
- principle site for modulation of pain
******
what does the substantia gelatinosa do?
it is where the C-fibers originate????? double check this
- it’s found in lamina II or III, and it’s the major site of action of opioids (shores said this in class) [this is rudy, btw]
what makes up the dorsal horn? laminia of 2nd order neurons? and what type of pathways
I-VI
and are afferent pathways
Dorsal vs Ventral location!!
real easy don’t fuck this one up!!!!!!!!!
dorsal back (like a dophiins fin)
ventral front
SECOND ORDER NEURONS:
Lamina I: does what? (or responds to what?)
responds to nociceptive stimuli from cutaneous and deep somatic tissue
SECOND ORDER NEURONS:
*********
what is located in the Lamina II [& maybe III]?
substantia gelatinosa
SECOND ORDER NEURONS:
what is the lamina II (III) for (substantia gelatinosa)
contains many interneurons responsible for processing and modulating nociceptive input from cutaneous tissue
SECOND ORDER NEURONS:
•**************
what is the major site for opioid actions
Lamina II (III?)
substantia gelatinosa
(ohhhhh light bulb thats why it is an important are!!)
SECOND ORDER NEURONS:
what do lamina I and V contain?
visceral afferents
SECOND ORDER NEURONS:
What does Lamina V respond to? and receive?
both noxious and non-noxious stimuli
recieves both somatic and visceral inputs
SECOND ORDER NEURONS:
what cross the midline to the level of origin to the contralateral side of the spinal cord ((doesn;t make sense to me?)
spinothalamic tract
SECOND ORDER NEURONS:
the spinothalamic tract is divided into what?
lateral and medial
SECOND ORDER NEURONS:
which spinothalmic tract, projects location, density, duration of pain in the VENTRAL posteriorlateral nucleus of the thalamus?
Lateral spinothalmic tract
SECOND ORDER NEURONS:
which spinothalmic tract, projects unpleasent emotionalperceptions of pain in the medial thalamus?
medial spinothalmic tract
SECOND ORDER NEURONS:
recap
what does the lateral spinothalmic tractdo?
projects location, density, duration of pain in the ventral posteriorlateral nucleus of the thalmus
SECOND ORDER NEURONS:
recap
what does the medial spinothalmic tract do?
projects unpleasent emotional perception of pain in the medial thalmus
THIRD ORDER NEURONS:
what the hell are they?
neurons in the head
THIRD ORDER NEURONS:
information is transfered up to where?
thalamus then to the somatosensory cortex
*****************
know this
what is the modulation of pain???
- impulses arise in the periventricular/periaquaductal gray matter of the brain stem
- impulses are transmitted through the RAPHE MAGNUS to the SUBSTANTIA GELATINOSA by way of the DORSOLATERAL FUNICULUS
(awesome remember opioiod work of the substantia gelatinosa=====thus blocking pain…. booom bitch instant mind fuck)
what is the modulation of pain??? this is extra to know still important but last slide if most important!!!
so well start were we left off
- impulses arise in the periventricular/periaquaductal gray matter of the brain stem
- impulses are transmitted through the RAPHE MAGNUS to the SUBSTANTIA GELATINOSA by way of the DORSOLATERAL FUNICULUS
- Action potentials @ the substantia gelantinosa activate ENKEPHALIN INTERNEURONS
- release of ENKEPHALIN decreases SUBSTANCE P release (reduction of # of pain impulses ascending in the lateral spinothalamic tract)
- action potentials descending in the DORSOLATERAL FUNICULUS also hyperpolarize cell bodies of the second order neurons in the pain pathway (reduction in the # of sction potentials int he ascending lateral spinothalmic tract the descending dorsolateral modulates pain)
Modulation of pain:
IV opioids produce analgesia how?
- inpart by initiating action potentials in the DESCENDING DORSOLATERAL FUNICULUS
- also act on other sites in the brain (limbic, hypothalamus, and thalamus) produce supraspinal analgesia primarily by mu-1 receptors
Modulation of pain:
Spinal analgesia?
mediated by mu-2 receptors occurs when the # of pain impulses passing through the SUBSTANTIA GELANTINOSA is decreased
Modulation of pain:
what is the difference b/t spinal and opioid analgesia receptors blockade for pain?
spinal mu-2
opioid mu-1 (maybe 2 also)
hmm interesting!!!!!!!!
Modulation of pain:
what does the spinalreticular pain pathway dresponsible for?
arousal and autonomic response to pain
Modulation of pain:
what is the spinalmesencephalic pathway for?
anti-nociceptive descending pathways b/c of it;s projections in the periductal gray area
Spinalanesthesia is what mu recptors?
supraspinal analgesia is what mu receptors
spinal- mu-2
supraspinal- mu1 and 2
FIBER SPECIFIC AFFERENTS: fast -sharp pain
is what fiber
A delta
FIBER SPECIFIC AFFERENTS: fast -sharp pain
A-delta fibers enter and leave where
- the tract of lissaeur
FIBER SPECIFIC AFFERENTS: fast -sharp pain
A-delta fibers terminate where?
rexed’s lamina I, V
FIBER SPECIFIC AFFERENTS:
fast -sharp pain
give the whole pathays(3 steps)
- A-delta fibers enter and leave the TRACT OF LISSAUER
- then enter the DORSAL HORN and terminate at the REXED’S LAMINA I, V
- 2nd order neurons leaving lamina I or V cross to the CONTRALATERAL LATERAL SPINOTHALMIC TRACT and ascend to the brain
FIBER SPECIFIC AFFERENTS: slow pain
what nerve fiber are we discussing?
C fibers
FIBER SPECIFIC AFFERENTS: slow pain
the C-fibers terminate primarily where?
Lamina II (III?) substantia gelatinosa
FIBER SPECIFIC AFFERENTS: slow pain
explain the whole pathway for slow pain ( 3 steps)
- the c-fibers terminate in teh LAMINA II (III?) SUBSTANTIA GELATINOSA
- interneurons transmit C-fiber impulses to LAMINA V
- Neurons leaving V cross immediattely to the contralateral lateral spinothalmic tract and ascend to the brain.
**********
primary NT for A-delta?
Glutamate
********
primary NT for C-fibers?
Supstance P
the primary NT for A-delta fibers (glutamate) does what?
binds to AMPA receptors on the postsynaptic membrane
The primary NT for C-fibers (Substance P) does what?
binds to NK-1 and the postsynaptic membrane
Tissue specific NT:
What do tissues release?
- seratonin
- histamine
- prostaglandins
- H+
- K+
Tissue specific NT:
what NT does plasma release?
- kinins
- histamine
- (platelets, basophls, granules of mast cells)
Tissue specific NT:
what NT do nerve terminals release
Substance P
What typ of pain is muscle joint pain?
Somatic
Describe somatic pain!
- Aching, often constant
- possibly dull or sharp
- exacerbated with movement
- well localized
What type of pain is organ or abdominal pain?
Visceral
Describe visceral pain
- constant crampy
- aching
- poorly localized
- reffered
Somatic structures: SKIN
A-delta high threshold mechanoreceptors (HTMs) deal with what type of pain>
noxiuos mechanical stimuli
Somatic structures: SKIN
A-delta mylelinated mechanothermal nocieptors (MMTNs) deal with what type of pain>?
noxious heat and mechanical stimuli
Somatic structures: SKIN
C-polymodal nociceptors (CPNs) deal with what pain?
- nocious mechanical, thermal, chemicl stimuli
- muscle joints, faciae, other deep somatic structures
Visceral structures:
C-fibers and A-delta fibers deal with what pains?
disease
inflammation
isometric contraction
ischemia
rapid distention
**************** one of his favorite slides***********
Muscle-Skeletal/ cardiac muscles
- Inervated by what nerves
- Characteristics of pain
- most intense when?
- the nociceptors undergo sensitation in response to what substances?
- A-delta and C-fibers
- Diffuse, poorly localized
- contraction and ischemia
- allogenic
**************** one of his favorite slides***********
Joint pain
- inervated by what nerves?
- repsnd only to what?
- can become sensitized with __________, leading to activation woth normal movement, or developing background discharge
- A-delta and C-fibers
- Extreme movement/pressure
- inflammation
**************** one of his favorite slides***********
bone pain
- what fibers?
- the fibers form a plexus around the ________.
- The _____ and ______ has no nociceptive fibers has the lowest threshold of deep somatic structures
- A-delta and C-fibers
- periosteum
- cortex and marrow
**************** one of his favorite slides***********
Visceral tissue
- what fibers?
- Is it part of ANS
- Insensitive to what?
- sensitive to what?
- A-delta and C-fibers
- nope
- curring, heating, pinching
- twisting and distention
Each fascical has both efferent and afferent fibers. this is refered to as the what?
reflex arch
LA SENSITIVITY:
nerve fibers order of sensitivity to LA?
Large myelinated > smaller myelinated > unmyelinated
LA SENSITIVITY:
Nerve fiber order of block?
- B
- C-& A-delta
- A-gamma
- A- beta
- A-alpha
LA SENSITIVITY:
so why is that last slide true??? see the picture
order of block
- B
- C and A-delta
- A-gamma
- A-beta
- A-aplha
Sensitiveity is largest myelinated at the highest
