Brainscape's Knowledge GenomeTM

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


See full index

Neurology > UMN and LMN > Flashcards

UMN and LMN Flashcards

1
Q

UMN division: Cortical = Pyramidal motor system

A
  • regulates LMN activity that results in highly skilled motor activity
  • includes discretely organized, interconnected white matter structures formed by axons that pass through the pyramids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

UMN system division: non-cortical = extrapyramidal motor system

A
  • regulates LMN activity responsible for muscle tone, posture, and stereotyped/coarse movement (lower level movement)
  • includes motor centers scattered in each division of the brain with axons that are not associated with the pyramids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Anatomy of pyramidal system: Motor cortex

A
  • Cell bodies located in the pre- and post- cruciate gyri depending on species
  • descending axons from the cell bodies contribute to the formation of discretely organized and identifiable bundles of white matter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

White matter structures of the pyramidal motor system

A
  • corona radiata: fan-shaped
  • internal capsule: coarse of white matter axons
  • Crus cerebri: at midbrain
  • Longitudinal fibers of the pons: at level of metencephalon
  • pyramids: at the level of myelencephalon
  • axons continue to form corticospinal tract (lateral and ventral divisions)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Tracts of the pyramidal system: Corticonuclear system

A

(named based on destination)

-from the pyramidal motor cortex to LMN nuclei in the brainstem of cranial nerves III-VII and IX-XII

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

Tracts of the pyramidal system: Corticospinal system

A
  • From the pyramidal motor cortex to LMN in the spinal cord
  • > lateral corticospinal tract: 75% of pyramidal fibers cross pyramidal decussation, descend into the spinal cord to regulate appropriate contralateral LMN in ventral gray column
  • > ventral corticospinal fibers: 25% of pyramidal fibers do not cross in the pyramid but descend ipsilaterally through rest of the brainstem and then in the ventral gray column
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cord location for corticospinal fibers

A

within lateral funiculus and ventral funiculus

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

Anatomy of the extrapyramidal motor system

A

extrapyramidal centers are found in all five divisions of the brain with some nuclei more important than others in animals

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

telencephalic centers

A
  • cerebral cortex - neurons scattered on the surface

- subcortical nuclei called basal ganglia forming an area known as the corpus striatum

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

Corpus Striatum

A
  • area of telencephalon under surface of the cortex formed by alternating bundles of white matter and extrapyramidal nuclei
    a) external capsule (white matter)
    b) lentiform nucleus - facilitates appropriate movement and inhibits inappropriate movement
    • putamen: receives information (afferent)
    • pallidum (globus pallidus): Sends information out of corpus striatum to other extrapramidal areas (efferent)
      c) internal capsule (white matter fibers)
      d) Caudate nucleus - receives information (afferent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cerebral input: Pyramidal system

A
  • Corticopontine fibers = Corticopontocerebellar tract
    • from the pyramidal motor cortex to pontine nucleus for synapse
    • fibers cross to form cortralateral middle cerebellar peduncle that enters cerebellum (pontocerebellar fibers)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cerebral input: Extrapyramidal system

A
  • Olivocerebellar tract

- olive nucleus: receives info from extrapyramidal structures and sends to the cerebellum as olivocerebellar fibers

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

Clinical signs of UMN disease

A

Due to loss of regulatory inhibition of the LMN; disturbance of mechanism for regulation of voluntary motor function and maintenance of muscle tone

1) hyperreflexia
2) hypertonus
3) spastic paralysis
4) slow muscular atrophy over time

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

anatomy of extrapyramidal motor system: Diencephalon

A
  • zona incerta
  • endopeduncular nucleus
  • subthalamic nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

anatomy of extrapyramidal motor system: Mesencephalon

A
  • substantia nigra (affected in parkinson’s dz)
  • tegmental nucleus
  • *RED NUCLEUS = most important extrapyramidal center in animals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Red Nucleus

A
  • afferent information: into the nucleus - info from motor cortex, other extrapyramidal nuclei, cerebellum
  • efferent information: out to the spinal cord for LMN regulation - rubrospinal tract in lateral funiculus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

anatomy of extrapyramidal motor system: metencephalon

A

-pontine reticular formation and nucleus (excitatory)
-axons cross to form the pontine reticulospinal tract
(also called the ventral reticulospinal tract)

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

anatomy of extrapyramidal motor system: Myelencephalon

A

-Medullary reticular formation and nucleus (inhibitory)
-axons cross to form the medullary reticulospinal tract
(also called the lateral reticulospinal tract)

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

extrapyramidal output to spinal cord: main paths

A

-rubrospinal, pontine reticulospinal, medullary reticulospinal represent summated output of extrapyramidal system to the spinal cord LMN

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

Summary of Pyramidal tract

A
  • corticonuclear tract to LMN nuclei in the brainstem to face (and head)
  • Corticospinal tracts to LMN in ventral gray horn of spinal cord limbs (and trunk)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Summary of extrapyramidal system

A

rubrospinal, pontine reticulospinal, and medullary reticulospinal tracts = output
vestibulospinal = important for regulation, posture, and m. tone

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

Upper Motor Neurons

A
  • neurons contained within CNS that regulate LMN in the brainstem and spinal cord
  • Function to initiate voluntary movement, maintain m. tone and posture, and regulate viscera
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Final common pathway

A
  • innervation to the largest target structure
    • convergence: number of fibers converging on a cell
    • summation: adds up all fibers coming down (excitatory and inhibitory fibers = inhibitory influence)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

component of the LMN system: spinal neurons

A
  • one functional group based on target structure but to cell sizes
    • ventral horn: neuron cell bodies classified by size and what they innervate
    • GSE neurons to extrafusal fiber: regular skeletal m. fibers (alpha motor neurons - large)
    • GSE neurons to intrafusal fiber: modified skeletal m. fiber - specialized m. spindle (gamma motor neurons - small)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

component of the LMN system: Cranial neurons

A
  • GSE (general somatic efferent) = voluntary skeletal m. located in head and face
  • SVE (special visceral efferent) = skeletal m. of branchial arch origin aka pharyngeal arch origin
  • GVE (general visceral efferent) = cardiac and smooth m., glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

reflex arc

A

receptor -> interneuron (usually) -> efferent fiber -> effector/target

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

monosynaptic arc

A

myotatic reflex (Ex. knee jerk)

28
Q

polysynaptic arc

A

more common, interneurons present

Ex. fibers traveling up and down forming fasiculus proprious

29
Q

lesion sites

A
  • Neuromuscular junctions: toxins block transmission
  • peripheral nerve: inflammation or trauma (ex. cut nerve)
  • spinal nerve proper: trauma, fracture, neoplasia (short segment where 2 branches have fusion at level of intervertebral foramen)
  • ventral root: trauma, fracture, neoplasia (initial part of nerve fiber coming from spinal cord)
  • cell body: pressure, ischemia (produce signs of LMN dz)
30
Q

LMN signs

A
  • hyporeflexia
  • hypotonia
  • flaccid paralysis
  • atrophy of muscle in relatively short time
31
Q

What produces cranial nerve nuclei (2)

A

Neurobiotaxis - cell body wants to be close to its target

columnar fragmentation - movement causes column to become fragmented

32
Q

Nucleus location for oculomotor nerve/CN III

A

Rostral colliculus

33
Q

Nucleus location for trochlear nerve/CN IV

A

Caudal colliculus

34
Q

Nucleus location for abducens nerve/CN VI

A

Caudal cerebellar peduncle

35
Q

Nucleus location for hypoglossal nerve/CN XII

A

Obex

36
Q

If CN III/IV/VI are affected, what general GSE signs will you see

A

Strabismus (extraocular mm.)

37
Q

If CN XII is affected, what general GSE signs will you see

A

Atrophy, usually on the side of the lesion

38
Q

GSE innervation and location

A

Innervation of extraocular and tongue mm., located at midline

39
Q

SVE innervation and location

A

Innervation of skeletal m. of branchial arch origin, most lateral

40
Q

GVE innervation and location

A

Visceral motor system and autonomic motor innervation, located between GSE and SVE

41
Q

SVE nuclei and nn.

A

CN 5, 7, 9, 10, 11

42
Q

Trigeminal n. origin

A

Motor nucleus of the trigeminal nerve, in metencephalon at level of the rostral cerebellar peduncle

43
Q

Trigeminal n. innervation

A

mm. of mastication - 3 mm. act to close, 1 to open (also innervated by facial n. so can still open)

44
Q

Trigeminal n. signs

A

Inability to close jaw (“dropped”)

45
Q

Facial n. origin

A

Motor nucleus of the facial nerve, in myelencephalon halfway b/w trapezoid body and olive, forms genu that goes around root for CN VI - can also be affected

46
Q

Facial n. Innervation

A

mm. of facial expression

47
Q

Facial n. signs

A

Facial paralysis

48
Q

CN IX-XII origin

A

Nucleus ambiguus

49
Q

CN IX and X innervation

A

Palate, pharynx, larynx, esophagus

50
Q

CN IX-XI signs

A

Difficulty swallowing = dysphagia, squeaky bark (voice box mm.)

51
Q

CN XI innervation (internal and external roots)

A
  • internal root - to larynx and esophagus with CN X

- external root - to cervical m.

52
Q

CN XI signs

A

Muscle atrophy (external root); internal root can’t be distinguished bc mixed with CN X

53
Q

2 neuron model for autonomic (symp and parasymp) innervation

A

Synapse in ganglion prior to teaching target of innervation; synapse in cranial part of system is a “named” or “terminal” ganglion

54
Q

Origin (preganglionic cell body) and synapse (postganglionic cell body) for parasymp nucleus CN III

A

Origin - Edinger Westphal

Synapse - ciliary ganglion

55
Q

Origin (preganglionic cell body) and synapse (postganglionic cell body) for parasymp nucleus CN VII

A

Origin - rostral salivatory, lacrimal

Synapse - mandibular and pterygopalatine ganglia

56
Q

Origin (preganglionic cell body) and synapse (postganglionic cell body) for parasymp nucleus CN IX

A

Origin - caudal salivatory

Synapse - otic ganglion

57
Q

Origin (preganglionic cell body) and synapse (postganglionic cell body) for parasymp nucleus CN X **synapse in a terminal ganglion (vs. named - all others)

A

Origin - dorsal vagal nucleus

Synapse - terminal ganglia in organ walls

58
Q

Functional LMN components in CN III

A

GSE - extraocular mm.

GVE - intraocular mm.

59
Q

Functional LMN components in CN IV

A

GSE - extraocular

60
Q

Functional LMN components in CN V

A

SVE - mastication

61
Q

Functional LMN components in CN VI

A

GSE - extraocular

62
Q

Functional LMN components in CN VII

A

SVE - facial expression

GVE - lacrimal and salivary gl.

63
Q

Functional LMN components in CN IX

A

SVE - pharyngeal mm., palate

GVE - salivary gl.

64
Q

Functional LMN components in CN X

A

SVE - pharynx, larynx

GVE - body organs, cardiac and smooth m.

65
Q

Functional LMN components in CN XI

A

SVE (external root) - cervical mm. (Disregard internal root - functionally part of CN X)

66
Q

Functional LMN components in CN XII

A

GSE - lingual mm.

Neurology (8 decks)

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