Neuro - Exam 2 - Part 3

Front 1

inflammatory pain

Back 1

pain resulting from long-term changes in nociceptor sensitivity to stimuli

Front 2

neuropathic pain

Back 2

irritation of conducting fibers of nociceptors

Front 3

central pain

Back 3

pain resulting from abnormal activity of neurons of the anterolateral system

Front 4

what is collectively true of inflammatory pain, neuropathic pain and central pain?

Back 4

often persist and are hard to treat

Front 5

Why do sensitized receptors respond more vigorously to stimuli than normal?

Back 5

b/c their threshold for activation is lowered

Front 6

why is a warm shower or a gentle pat on sunburned skin painful?

Back 6

b/c nociceptors in that area are SENSITIZED

Front 7

2 types of abnormality of stimulus detection

Back 7

hyperalgeisa

allodynia

Front 8

2 primary causes of nociceptor sensitization

Back 8

noxious stimuli cause release of toxic soup of chemicals from cells/tissues in vicinity of injury

axon reflex - neuroendocrine function of nociceptors

Front 9

substances released by cells in vicinity of injury, in response to noxious stimuli

Back 9

bradykinin

histamine

PGs

serotonin

K+

Front 10

which cause of nociceptor sensitization is primarily responsible for arthritis pain?

Back 10

toxic soup release

Front 11

axon reflex

Back 11

impulses that propagate centrally along sensory axons can depolarize terminal branches and cause release of other mediators from receptor endings

Front 12

what increases the blood flow that causes further receptor sensitization, edema and reddening of skin?

Back 12

axon reflex

Front 13

4 endogenous agents that activate nociceptors

Back 13

K+

serotonin (5-HT)

bradykinin

histamine

Front 14

3 endogenous agents that sensitize nociceptors

Back 14

PGs

LTs

Substance P

Front 15

3 pharmalogical approaches to managing hyperalgesia from inflammatory/arthritic pain

Back 15

block initial sensitization fo nociceptor endings with NSAIDs

block release of substance P from nociceptors that can sensitize neighboring receptors (eg: topical anesthetic creams, like capsaicin)

impede impulse conduction in afferent nerves with Lidocaine

Front 16

how do NSAIDs work?

Back 16

inhibit PG formation by inhibiting COX

Front 17

how do capsaicin creams work?

Back 17

depleting substance P from nociceptor nerve endings

Front 18

how does Lidocaine work?

Back 18

blocks voltage-gated Na+ channels and has generalized anesthetic, not analgesic effects

Front 19

central component to sensitization mediating inflammatory/arthritis pain involves what NT?

Back 19

glutamate

Front 20

which two excitatory amino acid channels does glutamate released from nociceptors act on?

Back 20

AMPA

NMDA

Front 21

What normally blocks NMDA?

Back 21

Mg2+

Front 22

What happens when Glu opens AMPA channels?

Back 22

Glu --> AMPA opens --> membrane potential depolarized --> NMDA channels become unblocked --> additional depolarization

Front 23

repeated activation of C fibers causes...

Back 23

a "wind up" or successive increase in repsonsiveness of dorsal horn neurons as NMDA channels lose their Mg2+ block and become activated

Front 24

central pain

Back 24

severe condition caused by damage to anterolateral system or its targets

Front 25

phantom limb pain is a form of what kind of pain?

Back 25

central pain

Front 26

phantom sensations

Back 26

sensations, including pain, emanating from the amputated limb

Front 27

phantom pain may be caused by...

Back 27

hyperactive neurons in the AL system from an imbalance between excitatory and inhibitory input following deafferentiation

Front 28

referred pain results from...

Back 28

activation of nociceptors

Front 29

referred pain

Back 29

condition in which pain following injury to an internal organ (by activation of visceronociceptors) is perceived as coming from other areas on body surface

Front 30

cause of referred pain

Back 30

convergence of somatic and visceral nociceptive inputs to DORSAL HORN SPINOTHALAMIC TRACT neurons

stimulus detection and condition are normal, but localization is faulty

Front 31

what two afferent types converge to cause referred pain?

where do they converge?

Back 31

nociceptive visceral afferents and afferents innervating specific somatic areas converge

on same anterolateral system projection neuron

Front 32

Radicular pain

Back 32

pain of neural, NOT sensory, originn

Front 33

radicular pain arises from mechanisms that BYPASS ____

Back 33

radicular pain arises from mechanisms that bypass the normal activation of nociceptors

Front 34

2 causes of MECHANICAL radicular pain

Back 34

sciatica (herniated intervertebral disc)

spinal stenosis

Front 35

4 categories of radicular pain

Back 35

mechanical
increase in nerve excitability w/ ectopic impulse initiation

inflammation or irritation of chronically injured peripheral nerves

ectopic impulses propagating peripherally, releasing neuroactive agents that sensitize its neighbors

Front 36

which ganglia are particularly sensitive to mechanical compression

Back 36

dorsal root ganglia

especially following ischemia

Front 37

only link between nervous system and skeletal muscles

Back 37

motor neurons

Front 38

Sherrington's "final common path"

Back 38

motor neurons serve as the only link between the nervous system and skeletal muscles

Front 39

lower motor neurons, aka:

Back 39

spinal motor neurons

Front 40

brainstem and cortical motor neurons, aka:

Back 40

upper motor neurons

Front 41

upper motor neurons influence the activity of _____, via _____

Back 41

upper motor neurons influence the activity of lower motor neurons via descending projections

Front 42

nuclei and laminae in which spinal motor neurons are located?

Back 42

lamina IX

somatic motor nuclei

Front 43

alpha motor neurons

Back 43

motor neurons that innervate extrafusal muscle fibers

Front 44

what type of synapse(by NT) is the NMJ?

Back 44

cholinergic

Front 45

motor unit

Back 45

a single alpha motor neuron and all the muscle fibers it innervates

Front 46

the nervous system acts only on ____

Back 46

motor units

Front 47

nervous system controls muscle contraction by varying which 2 things?

Back 47

rate coding: regulating motor neuron FIRING RATE

recruiting motor units

Front 48

size of motor unit depends on...

Back 48

number of muscle fibers innervated

Front 49

sense organs innervating muscles and tendons provide ______ to _____ neurons

Back 49

sense organs innervating muscles and tendons provide PROPRIOCEPTIVE SENSORY INPUT to VENTRAL HORN MOTOR NEURONS

Front 50

two types of sensory fibers innervating muscle spindles

Back 50

Group Ia - signal both velocity & length

Group II - signal length only

Front 51

GTOs contribute to ______

Back 51

fine adjustments in muscle force needed during voluntary movements

Front 52

only sensory receiver to receive efferent connections from the nervous system

Back 52

muscle spindles

Front 53

efferent innervation from nervous system to muscle spindles is through ____ fibers

Back 53

gamma motor neurons

Front 54

gamma motor neurons regulate...

Back 54

gamma motor neurons regulate the sensitivity of muscle spindles during movement

Front 55

type of neuron thought to play a role in the development of spasticity after spinal cord injuries

Back 55

gamma motor neurons

Front 56

alpha-gamma coactivation

Back 56

during muscle contraction, the nervous system fires gamma motor neurons at the same time as alpha motor neurons

Front 57

alpha-gamma coactivation preserves...

Back 57

proprioceptive input to the nervous system during movement by keeping muscle spindles from going slack during extrafusal muscle contraction and no longer providing information about muscle length

Front 58

2 types of spinal reflexes

Back 58

tendon reflexes

flexor - crossed extension reflex

Front 59

2 types of tendon reflexes

Back 59

stretch reflex

inverse myotactic reflex

Front 60

stretch reflex, aka: ____ or _____

Back 60

stretch reflex, aka: myotatic or monosynaptic reflex

Front 61

what nerves mediate stretch reflex

Back 61

Group Ia afferents innervating muscle spindles

Front 62

what activates stretch reflex

Back 62

tapping any large tendon

Front 63

best known example of stretch reflex

Back 63

patellar tendon reflex

Front 64

sequence of events in stretch reflex

Back 64

tap patellar tendon --> stretch spindle --> excite sensory endings --> impulses conducted along afferent axons to motor neurons --> motor neurons excite quadriceps motor neurons --> contraction of muscle

Front 65

reciprocal inhibition

Back 65

one group of muscles is excited while the antagonist muscles are inhibited

Front 66

function of reciprocal inhibition

Back 66

prevents reflexive contraction of the antagonist muscles

Front 67

what reflex counteracts muscle stretch during contraction or passive, fatigue-produced muscle lengthening (e.g.: when standing)

Back 67

length-maintaining reflex (type of tendon reflex)

Front 68

inverse myotatic reflex regulates

Back 68

muscle tension and stiffness

Front 69

inverse myotatic reflex is activated by which neurons?

Back 69

group Ib fibers innervating GTOs

Front 70

which has a higher threshold, stretch reflex or inverse stretch reflex?

Back 70

inverse stretch reflex

(not activated by tendon tap)

Front 71

sequence of events in inverse myotatic reflex

Back 71

stretch tendon --> excite GTOs --> impulses conducted to inhibitory interneurons --> inhibit motor neurons that innervate muscle attached to tendon

Front 72

autogenic inhibition

Back 72

muscle group inhibited by its own sensory input

muscle tension leads to inhibition of motor neurons

Front 73

which reflex helps maintain posture during standing

Back 73

inverse myotatic reflex

Front 74

flexor-crossed extension reflex controls _____ and involves ____ spinal segments

Back 74

MUSCULATURE acting around MULTIPLE JOINTS

and involves SEVERAL spinal segments

Front 75

which reflex is polysynaptic?

Back 75

flexor-crossed extension reflex

Front 76

flexor-crossed extension reflex, aka:

Back 76

withdrawal reflex

Front 77

protective function of flexor-crossed extension reflex

Back 77

automatically withdraws limb from noxious stimulus and transfers weight to opposite limb

Front 78

what structures initiate the flexor-crossed extension reflex?

Back 78

A-delta nociceptors

Front 79

mechanism of flexor-crossed extension reflex

Back 79

nociceptive input to the Al system is relayed to excitatory and inhibitory interneurons that synapse on the ipsilateral and contralateral flexor and extensor motor neurons

Front 80

sequence of events in flexor-crossed extension reflex

Back 80

painful stimulus --> excite flexor motor neurons --> rapid withdrawal of limb away from harmful object --> excite contralateral extensors and inhibit contralateral flexors to enable opp. limb to support body weight.

Front 81

bottom line, what does withdrawal reflex produce?

Back 81

ipsilateral flexion & contralateral extension

Front 82

spinal reflexes are used as a diagnostic tool for evaluating what?

Back 82

motor system dysfunction

Front 83

spinal cord injury involving damage to descending pyramidal tract axons in the lateral funiculi produce _____

Back 83

"upper motor neuron signs"

Front 84

2 general categories of "upper motor neuron signs"

Back 84

spinal "shock" - initial flaccid paralysis of muscles below injury

spasticity - increased resistance of muscles to passive movement

Front 85

4 types of spasticity

Back 85

hypertonia

hyperreflexia

clasp-knife response

clonus

Front 86

hypertonia

Back 86

increased resistance to passive manipulation

Front 87

hyperreflexia

Back 87

exaggerated response to tendon tap

Front 88

clasp-knife response

Back 88

increased resistance to displacement of a joint - suddenly collapses like the closing of a pocket knife

Front 89

clonus

Back 89

repetitive alternating contraction of flexors and extensors, usu. at a distal joint (ankle)

often present with hypertonia and hyperreflexia

Front 90

mechanisms underlying hypertonia and hyperreflexia

Back 90

excessive activation of gamma motor neurons from loss of descending inhibitory input

involves gamma loop pathway

Front 91

gamma loop circuit

Back 91

gamma motor neuron --> intrafusal fiber --> Ia afferent --> alpha motor neuron --> extrafusal fibers

Front 92

intrafusal muscle fibers

Back 92

skeletal muscle fibers that comprise the muscle spindle and are innervated by gamma motor neurons.

Front 93

extrafusal muscle fibers

Back 93

innervated by alpha motor neurons

cause the muscle to contract

Front 94

clasp knife response mediated by...

Back 94

autogenic inhibition from GTOs (inverse myotatic reflex)

Front 95

Sensory receptors that drive autonomic activity may originate from which three regions?

Back 95

viscera (visceral sensory)

body surface (somatic sensory)

external environment (special sensory)

Front 96

receptors of visceral afferents are usually located where?

Back 96

in the walls of hollow organs

Front 97

receptors located in organ walls are called ____

Back 97

intramural

Front 98

are mechanoreceptors in organs usually exposed to the organ lumen?

Back 98

no

Front 99

what type of receptors are sensitive to the following:

oxygen tension in aortic bodies

pH in the stomach and duodenum

Back 99

chemoreceptors

Front 100

visceral pain is mediated by ____

Back 100

nociceptors in the walls of organs

Front 101

axons of spinal sensory neurons that mediate visceral pain usually travel along side _____

Back 101

sympathetic nerves

Front 102

3 components of most autonomic reflexes

Back 102

somatovisceral

viserosomatic

viscerovisceral

Front 103

what type of reflex is:

muscle movement eliciting reflex vasodilation

Back 103

somatovisceral

Front 104

what type of reflex is:

a strong intestinal contraction (usu. with pain) results in abdominal muscle contraction

Back 104

viscerosomatic

Front 105

what type of reflex is:

distention of one region of the intestin results in decreased motility in other regions of the intestine and changes in blood flow

Back 105

viscerovisceral

Front 106

basic visceral reflex arc consists of what 3 things?

Back 106

afferent, spinal sensory neuron

preganglionic neuron in the brainstem or intermediolateral region of spinal cord

postganglionic neuron in an autonomic ganglion that innervates the effector organ

Front 107

a reflex that involves spinal pathways may ascend to reach...

Back 107

higher centers in the brainstem or hypothalamus

Front 108

sympathetic innervation of pelvic organs originates in what region of the spinal cord?

Back 108

LUMBAR

Front 109

all autonomics are primarily release which NT?

Back 109

ACh

Front 110

in which nucleus of the spinal cord are preganglionic autonomic cell bodies found?

Back 110

intermediolateral nucleus

Front 111

pudendal nerve supplies what kind of innervation to which part of the urinary tract?

Back 111

pudendal nerve supplies SOMATIC innervation to the EXTERNAL URINARY SPHINCTER

Front 112

pelvic nerve supplies what kind of innervation to which part of the urinary tract?

effect?

Back 112

pelvic nerve supplies PARASYMPATHETIC innervation to the DETRUSOR MUSCLE of the bladder.

Causes the bladder to CONTRACT.

Front 113

The hypogastric nerve supplies what kind of innervation to which part of the urinary tract?

effect?

Back 113

They HYPOGASTRIC nerve supplies SYMPATHETIC innervation to the DETRUSOR MUSCLE of the bladder.

Causes bladder relaxation during filling.

Front 114

Fibers that provide principal excitatory input to bladder smooth muscle

Back 114

parasympathetic efferent fibers of pelvic nerves

Front 115

autonomic afferents innervating the bladder are sensitive to what 2 things?

Back 115

distention & pain

Front 116

sympathetic efferents of hypogastric nerves are

excitatory to _____

& inhibitory to ____

Back 116

sympathetic efferents of hypogastric nerves are

excitatory to trigone muscle

inhibitory to detrusor muscle

Front 117

function of trigone

Back 117

signals brain that micturition threshold has been reached

Front 118

what occurs during the voiding phase of the micturition reflex?

Back 118

destrusor muscle contracts

muscles of external urethral sphincter & pelvic floor muscles relax

Front 119

what ends the filling phase?

Back 119

pressure reaches the micturition threshold

Front 120

where are reflex "centers" located?

Back 120

spinal cord & brain

Front 121

where is parasympathetic reflex center located?

Back 121

SACRAL spinal cord

Front 122

where are sympathetic reflex centers located?

Back 122

LUMBAR spinal cord

Front 123

spinal reflex centers are under the control of ____ centers

Back 123

SUPRASPINAL

Front 124

chain of command in micturition reflex

Back 124

cortical and diencephalic centers -->

brainstem centers -->

sacral centers

Front 125

effect of spinal shock on micturition

Back 125

no reflex emptying of the bladder

Front 126

neurogenic bladder

Back 126

any dysfunction of the bladder caused by a lesion of the nervous system

Front 127

where must the spinal cord be transected, given SCI, so that the spinal voiding reflex will operate?

Back 127

above the lumbar region

Front 128

transections above the lumbar region cause ______ bladder

Back 128

automatic, or uninhibited, bladder

Front 129

2 causes of automatic bladder

Back 129

spine transection above the lumbar region

Upper motor neuron region interrupting voluntary pathways to pontine micturition center

Front 130

If sacral spinal cord is damaged, a ____ bladder results

Back 130

flaccid or atonic

Front 131

mechanism leading to flaccid bladder

Back 131

sacral spinal cord damage --> reflex pathway and preganglionic parasympathetic pathways damage --> loss of bladder contraction signal

Front 132

cystometrogram

Back 132

graphic record of pressure within bladder

Front 133

normal micturition threshold

Back 133

400-600 mL

Front 134

3 successive phases of male sexual response

Back 134

penile erection

emission of semen into posterior urethra

ejaculation of semen from anterior urethra

Front 135

start/stop points for male orgasm

Back 135

orgasm beings with or before emission and ends with the end of ejaculation

Front 136

Role of parasympathetic efferents in penile erection

Back 136

dilate cavernosal and helical arteries --> increased blood flow to lacunar spaces --> engorgement

engorgement --> compression of subtunical venules --> decreased blood outflow from penis --> further engorgement

Front 137

activation of which nerves cause emission and ejaculation?

Back 137

sympathetic efferents in lower thoracic and upper lumbar cord become activated

Front 138

the sympathetic outflow that causes emission/ejaculation causes what sub-steps?

Back 138

contraction of smooth muscle in the epididymis, vas deferens, seminal vesicles and propstate

--> propulsion of semen into posterior urethra

Front 139

ejaculation is what kind of reflex?

Back 139

spinal cord mediated

Front 140

what triggers the ejaculation reflex?

Back 140

excitation of afferents from pr0ostate and posterior urethra

Front 141

activation of somatic efferents during ejaculation causes...

Back 141

tonic-clonic contractions of bulbocavernosus and ischiocavernosus

and of pelvic floor muscles

Front 142

afferents from which spinal regions participate in sexual reflex activation in the female?

Back 142

lumbar & sacral afferents

Front 143

what happens to the uterus during sexual arousal?

Back 143

uterus rises in the pelvis so that the cervix is moved away from the posterior wall of the vagina

Front 144

sensory innervation from the penis/clit is conveyed on which nerve?

Back 144

dorsal nerve of the clit/penis

Front 145

dorsal nerve of the clit is a branch of which nerve?

Back 145

pudendal nerve

Front 146

activation of parasympathetic efferent pathways in the female pelvis cause ____

& release ___, ____ and _____

Back 146

activation of parasympathetic efferent pathways in the female pelvis cause VASODILATION

and release ACh, VIP & NO (vasodilatory substances)

Front 147

Sympathetic postganglionic fibers with cell bodies in the _____ plexus innervate female genitalia and cause _____ & _____

Back 147

Sympathetic postganglionic fibers with cell bodies in the INFERIOR MESENTERIC PLEXUS innervate female genitalia and cause VASOCONSTRICTION and DETUMESCENCE

Front 148

are visceral afferent fibers myelinated?

Back 148

NO. Visceral afferent fibers are UNmyelinated.

Front 149

Visceral pain usually travels in ____ pathways.

Back 149

Sympathetic pathways.

Front 150

Autonomic dysreflexia

Back 150

acute syndrom of excessive, uncontrolled sympathetic output

Front 151

Autonomic dysreflexia is seen in patients who..

Back 151

have had spinal cord injury, usually at or above T6

Front 152

Spinal reflex pathways BELOW the level of the lesion remain intact, but ____ is interrupted.

Back 152

communication from the brain

Front 153

descending autonomic input to the autonomic preganglionic neurons is generally ____ (excitatory/inhibitory)

Back 153

inhibitory

Front 154

when descending inhibitory input is interrupted by SCI, autononic reflexes ...

Back 154

operate unopposed

Front 155

main findings of autonomic dysreflexia

Back 155

elevated BP

bradycardia

Front 156

presenting symptoms of autonomic dysreflexia

Back 156

bilateral, pounding headache

sweating above level of injury

nasal congestion, malaise and nausea

Front 157

most common precipitating factors of autonomic dysreflexia symptoms

Back 157

full bladder or full rectum