Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuroanatomy > Exam II > Flashcards

Exam II Flashcards

1
Q

Muscle spindles

A

detect changes in LENGTH of a muscle. located in parallel with the extrafusal muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Are muscle receptors intrafusal or extrafusal?

A

Intrafusal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Primary annulospiral (Type 1A) Muscle Spindle

A

Sensory innervation, respond to SUDDEN changes in length. Wrap around mid portion of nuclear bags and chains. Branches come off the 1A & synapse on interneuron to inhibit the antagonist muscles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Secondary (Type II) Muscle Spindle

A

Sensory Innervation. Wraps around distal end of chains. Responds to SLOW CHANGES in length.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Gamma Motor neurons

A

Stimulate nuclear bag and nuclear chain fibers (intrafusal). Keep the muscle on a constant slight stretch to enhance the muscle spindles ability to respond to stretches of the muscle at all parts of the range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Alpha motor neurons

A

stimulate the extrafusal muscle fibers (actin & myosin), when stimulated the entire fiber shortens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain how gamma motor neurons work.

A

cause the muscle spindle to lengthen while the muscle is contracting & shortening. This maintains the sensitivity of the spindle throughout the range of the muscle length.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Alpha-gamma coactivation

A

Spindle lengthens while the muscle shortens. Provides constant feedback to the CNS to stimulate alpha motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Monosynaptic reflex (myotatic)

A

1A primary annulospiral synapse DIRECTLY on alpha motor neurons. The muscle spindle are stretched, stimulating the 1A, causing the alpha motor neurons to fire, causing contraction of the muscle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Flexor (withdrawal) reflex

A

NOT monosynaptic. Sensory neuron synapses on a pool of interneurons. Example: free nerve endings synapse on interneurons which synapse on alpha motor neurons which remove the extremity from the object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Tonic Muscle Stretch Reflex

A

Only w/ UMN lesions. Reflex muscle contraction continues as long as a stretch is maintained. Typically the sensory afferents send info from muscle spindles to interneurons in spinal cord (LMN), in normal pts this is inhibited but with LMN lesion the inhibition is lost thus the reflex is present.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Golgi tendon organs

A

Sensory type 1B. located at myotendinous junction, detects tension in the tendon. Connected in series (perpendicular with the extrafusal fibers) Active when extrafusal fibers contract or are lengthened to end range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Traditional sequence of GTO

A

tension in tendon –> AP in type 1B fibers –> inhibitory signal to alpha motor neuron (muscle relaxes). Also stimulates the antagonist muscle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Autogenic inhibition

A

Inhibition of alpha motor neurons that innervate the muscle in which the GTO resides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Current theory of GTO function?

A

Contribute to proprioception by causing stimulation and inhibition of motor neurons during functional activities. Like walking for example (facilitates gastroc during stance contracts it during swing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the reliability of testing skin sensation dependent on?

A

Cognitive state & level of arousal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Testing pain sensation

A

nociceptive free nerve endings. prick them with something sharp.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Testing temperature sensation

A

free nerve endings/krause bulbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Testing touch sensation

A

free nerve endings, hair follicles, krause end bulbs
generalized (crude) - cotton ball over diffuse area or along dermatome or peripheral nerve distribution
localized (fine) - specific area of skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Efferent peripheral nerves

A

Aa (large myelinated, innervate extrafusal fibers), Ay (innervate intrafusal fibers), B (preganglionic autonomic nervous system, C (postganglionic fibers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Afferent peripheral nerves

A

1a (muscle spindle), 1b (GTO), II (muscle spindle), III (fast pain), C [type IV] slow pain, A-beta (“close the gate”)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

neuropraxia (class I)

A

traumatic myelinopathy - no axonal disruption, repair within 3 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

axotmesis (class II)

A

traumatic axonopathy - axon disrupted but not endoneurium, still contained so better chance of recovery. normal EMG changes 2-3 weeks, recovery 6 weeks to 6 months, maybe longer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

neurotmesis (class III)

A

severance - axon and endoneurium disrupted, need surgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Synkinesis

A

totally disrupted nerve reconnects with another nerve so theres an abnormal connection when that nerve fires.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Axons re-grow….

A

at a rate of 1-4 mm/day (1 in per month)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What nerves are affected first in compression injuries?

A

large myelinated neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Sequence of sensory loss

A

conscious proprioception & fine discriminatory touch –> cold sensation –> fast sharp pain sensation –> heat sensation –> dull (slow) pain sensation (return of sensation is reverse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Wallerian degeneration

A

disconnected distal stump undergoes swelling, fragmentation and phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Central chromatolysis

A

degenerative changes of clusters of rER (nissl bodies) that can result in death of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Axonal regrowth connecting the proximal and distal stump

A

schwann cells from the proximal stump secrete NGF, proliferate and fill the space within the endoneurium and form an intact tunnel between the proximal and distal stumps.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Collateral sprouting

A

denervated post-synaptic cells are reinnervated by branches of intact neighboring neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Regenerative sprouting

A

regenerating axon innervates a new post-synaptic cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is neuropathic pain?

A

pain arising as a direct consequence of nerve injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Symptoms of neuropathic pain

A

paresthesia, dysesthesia, allodynia, secondary hyperalgesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

paresthesia

A

painless abnormal sensations such as tingling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

dysesthesia

A

Unpleasant abnormal sensations such as shooting or burning

38
Q

Allodynia

A

pain evoked by stimulus that would not normally cause pain (light touch)

39
Q

Secondary hyperalgesia

A

hypersensitivity to mildly painful stimulus to uninjured tissue

40
Q

Ectopic foci

A

increased production and insertion of ion channels in demyelinated areas, becomes an area capable of generating action potentials

41
Q

Ephaptic transmission

A

a “cross-talk” of APs from one demyelinated axon to another demyelinated axon

42
Q

Central sensitization

A

increased production of NT’s and receptors in neurons in spinal cord and brain. Excessive neural activity disproportionate to incoming nociceptive signals. (fibromyalgia, barre virus, lots of diffuse pain)

43
Q

What is a lower motor neuron?

A

alpha motor neuron cell body and its axon.

44
Q

What is Henneman’s size principle?

A

The body recruits slow twitch first, then fast twitch recruitment.

45
Q

S/S of LMN

A

flaccid paralysis or weakness, diminished/absent reflexes, fasciculaitons (spontaneous contractions - muscle cells have more AcH receptors and are hypersensitive), atrophy, sensory loss/paresthesias

46
Q

Mononeuropathy

A

involves one peripheral nerve

47
Q

Polyneuropathy

A

symmetrical involvement of more than one nerve in the same region (diabetic neuropathy, guillan-barre)

48
Q

Radiculopathy

A

Damage to nerve root

49
Q

Multiple Mononeuropathy

A

asymmetrical involvement of 2 or more nerves often due to ischemia of individual nerves

50
Q

Common causes of peripheral neuropathies

A

Infections, immune disorders, trauma, vitamin deficiencies, diabetes, impaired glucose tolerance, idiopathic

51
Q

Clinical signs to detect peripheral neuropathies

A

absence or asymmetrical decrease of a reflex (ankle jerk reflex), impaired pallesthesia, impaired proprioception, paresthesias, muscle weakness

52
Q

Diabetic Neuropathy

A

glove and stocking distribution, axons and myelin damaged
S/S - pain, dysesthesias, impaired pallesthesia, hyporeflexia
long term - motor loss, bone resorption
Pain can be treated with lyrica (pregabalin) (binds to voltage gated Ca2+ channels and blocks release of substance P)

53
Q

Bell’s Palsy

A

etiology unknown (maybe viral), inflammation of CN 12, pain behind the mandible 24-48 hrs before one sided facial paralysis. 2/3 of cases spontaneously recover within 3 months.

54
Q

Deep peroneal nerve pathology

A

MOI usually pressure on head of fibula

S/S - weakness or dorsiflexion, decreased sensation in area between great and second toe.

55
Q

Herniated NP

A

C5/C6 disc (C6 nerve root), C6/C7 disc (C7 nerve root)

L4/L5 disc (L5 nerve root)
L5/SI disc (S1 nerve root)

56
Q

Guillian-Barre Syndrome

A 
possibly autoimmune (antibodies attack schwann cells), possibly triggered by viral or bacterial infection. 
S/S: ascending paralysis distal to proximal, decreased reflexes, ANS dysfunction (decreased CO, arrythmias, peripheral edema, urinary retention), demyelination (medical emergency)
57
Q

Polio/post-polio syndrome

A

Eventual degeneration of collateral branches of surviving neurons resulting in new onset of progressive weakness/fatigue, muscle cramping and joint pain.

58
Q

Charcot-Marie-Tooth Disease

A

Also known as hereditary motor and sensory neuropathy, genetic mutations cause damage to axons and myelin
S/S - paresis below the knee resulting resulting in foot drop w/ steppage gait pattern, pain, pes cavus/ hammer toes/claw toes, decreased touch sensation, muscle atrophy, hand and forearms may be affected.

59
Q

Spinal cord

A

from foramen magnum to L1/L2 in adults

60
Q

Cervical Enlargement

A

C4-T1

61
Q

Lumbar Enlargement

A

L2-S2

62
Q

Thecal (Dural) Sac

A

Dura and arachnoid together = dural sac, coccygeal ligament attaches teh dural sac to the sacrum

63
Q

Epidural Space

A

space b/t the thecal sac and teh bony vertebral canal , filled w/ blood vessels and fat

64
Q

Dorsal Gray Horn

A

Substantia gelatinosa (II), lamina V (T-cells, transmitting the sensations of pain and temperature), nucleus proprius ( III/ IV, origin of contralateral ventral spinothalamic tract - general crude touch)

65
Q

Ventral Medial Gray Horn

A

motor neurons to the trunk musculature, at ALL levels of the spinal cord

66
Q

Ventral Lateral Gray Horn

A

motor neurons to the extremities, only at the cervical and lumbar enlargements.

67
Q

Interomediolateral cell column

A

T1-L3 (preganglionic sympathetics cell bodies) & S2-S4 (preganglionic parasympathetics cell bodies)

68
Q

Dorsal nucleus of Clarke

A

Ipsilateral dorsal spinocerebellar tract for concious nad unconscious proprioception of LE

69
Q

Other things in the ventral gray horn

A

Spinal Accessory nucleus (C1-C5), phrenic nucleus (C3,4,5), Onuf nucleus (S2, S3, S4 –> voluntary control of the urethral and anal sphincters)

70
Q

Sacral Sparing

A

indicates incomplete SCI, central lesion affects proximal muscles first. The sacral innervated legs/feet affected last, perianal sensation and toe flexion intact.

71
Q

Anterior Spinal artery

A

supplies a lot of the anterior part of the spinal cord (ventral gray matter)

72
Q

Posterior spinal artery

A

Posterior spinal cord

73
Q

Segmental and medullary arteries

A

auxiliary blood to SC. Travel with the spinal nerves

74
Q

Reciprocal Inhibition

A

Inhibit motor neurons of antagonistic muscles during voluntary motion, inhibits antagonist during reflex testing, can be suppressed by: co-contraction, anxiety, learning new activity, anticipating uncontrolled movements

75
Q

Non-reciprocal Inhibition

A

Inhibit motor neurons of agonists, antagonists, and synergists throughout the limb to allow smooth movement.

76
Q

Recurrent inhibition

A

inhibits agonist motor neuron and synergists. “Renshaw cell”, dampens muscle activation to allow smooth movement

77
Q

Stepping Pattern Generators

A

POOLS of interneurons that are normally activated during the initiation of walking (in the gray matter), help produce the rhythmic movements of walking.

78
Q

Why is the White matter of the spinal cord white

A

because most of the axons are myelinated and teh high fat content in myelin gives it a whitish appearance.

79
Q

Dorsal funiculus

A

Ascending tracts - White matter - R & L sides separated by the dorsal median septum. Contains Fasciculus gracilus & cuneatus.

80
Q

Fasciculus gracilus & Fasciculus cuneatus

A

located throughout the spinal cord (gracilus), located at spinal cord segments T6 and above (cuneatus). TRANSMIT: 2 point discrimination, vibration, fine discriminatory touch and position sense from IPSILATERAL lower trunk/LE (gracilus) & upper trunk/UE (cuneatus)

81
Q

Tabes dorsalis

A

a disease process of the dorsal spinal cord –> syphilis, degeneration of dorsal column axons, loss of previously indicated sensations, be losing 2 point discrim, vibration, fine discrim touch.

82
Q

Lateral funiculus

A

descending tracts –> lateral corticospinal tract, raphe spinal tract, hypothalamospinal tract.

83
Q

Lateral corticospinal tract

A

descending axons from CL pre-motor, pre-central gyri to motor neurons of extremity muscles

84
Q

Raphe spinal tract

A

Descending axons from brainstem that synapse on neurons in dorsal gray horn to modify pain perception

85
Q

Hypothalamospinal tract

A

descending axons from hypothalamus to autonomic neurons in spinal cord

86
Q

Components of Spinal Nerves

A

ventral rootlets/roots, dorsal roots/rootlets, spinal nerves

87
Q

Ventral roots/rootlets

A

Axons of alpha and gamma motor neurons, axons of pre-ganglionic sym. (T1-L3) and pre-ganglionic parasym. (S2-S4 )

88
Q

Dorsal roots/rootlets

A

central processes of sensory neurons

89
Q

Spinal Nerves

A

Ventral and dorsal roots converge → through IV foramen→ split into dorsal and ventral primary rami

90
Q

dermatomes

A

Sensory innervation of skin from one spinal cord segment

91
Q

myotomes

A

Skeletal musculature innervated by motor neurons from one spinal cord level

Neuroanatomy (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions