Brainscape's Knowledge GenomeTM

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


See full index

Neuro > CH 8: Motor Pathways > Flashcards

CH 8: Motor Pathways Flashcards

1
Q

Brodmann areas:

A

based on differences in cytoarchitecture in the cerebral cortex

52 anatomic areas

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

what area is the primary motor area?

A

Brodmann’s area 4

lies in the precentreal gyrus and paracentral lobule of the frontal lob

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

the left motor strip of the primary motor area controls the ..?

A

right side of the body

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

the right motor strip of the primary motor area controls the …?

A

left side of the body

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

neurons in the lowest lateral part of the primary motor area influence the:

followed in:

A

larynx and tongue

followed in upward sequence by neurons affecting the face, thumb, hand, forearm, upper arm, thorax, abdomen, thight, leg, foot and perineal muscles

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

the neurons controlling the leg, foot and perineal muscles are in the :

A

paracentral lobula

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

areas for the hand, tongue and larynx are :

A

disproportionally large and conform to the development of elaborate motor control of these muscle groups

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

what is a homunculus?

A

the functional map of the motor cortex

resembles a distorted image of the body turned upside down and reversed left for right

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

immediately rostral to the primary motor area lies the:

A

premotor cortex (Brodmann’s area 6) on the lateral surface of the hemispheres

contains a homunculus similar to the one in area 4

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

what is the supplementary motor area?

A

the most medial aspect of area 6 can be observed on a midsagittal section of the brain just rostral to the paracentral lobule

also contains a functional map of body movements

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

what are additional regions of cerebral cortex that can influence movement?

A

Brodmann’s areas 3,1,2 on the postcentral gyrus

and the secondary motor area

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

where is the secondary motor area?

A

where the pre and post central gyri are continuous at the base of the central sulcus

overlaps the secondary somatosensory cortex

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

what is brodmann’s area 8 called?

A

frontal eye fields

contains neurons that specifically influence eye movements

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

the brainstem and the SC contain pattern generators for:

A

complex movements such as locomotion and other rhythmic activities

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

the descending pathways of the NS have the important task of:

A

interacting with and controlling lower-level neuronal patterns of discharge in a hierachical manner

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

at the level of the cerebral cortex, individual neurons can:

A

control the contractions of individual muscles and can determine the force of these contractions

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

populations of motor cortical neurons act together to:

A

specify the direction of movements and the force of movements

these functions pertain not only to neurons in the primary motor cortex but also to those in the premotor, supplementary, and postcentral regions

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

the premotor and supplementary motor areas are important in:

A

planning movements

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

the supplementary motor area appears to have a special role in:

A

integrating movements performed simultaneously on both sides of the body

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

skeletal muscle activity results from the:

A

net influence of higher nervous system structures on motoneurons of the SC and cranial nerve nuclei

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

what are lower motor neurons?

A

collectively SC and brain stem neurons provide the final direct link with muscles through neuromuscular junctions (motor end plates)

their cell bodies reside within the CNS and their axons make synaptic contact with extrafusal and intrafusal muscle fibers of somatic and branchiomeric origin

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

somatic muscle fibers derive from the:

A

myotomes of true somites in the developing embryo

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

branchiomeric muscles develop from:

A

the branchial arches of the embryo

are not true somites but muscles develop from them
like somatic muscle they are striated and under voluntary control

includes muscles of mastication and facial expression, and muscles of the pharynx and larynx

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

what are upper motoneurons?

A

regulate lower motoneuron activity

the cerebral cortex, cerebellum and basal ganglia control these descending pathways either directly or indirectly

synapse directly or through interneurons on alpha, beta and gamma motoneurons in the SC and cranial nerve nuclei

contained completely within the CNS

refers to the corticospinal tract and the corticobulbar tract

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

the corticospinal tract is also know as:

A

the pyramidal tract

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

what does the corticospinal tract control?

A

primarilly skilled movements of the distal muscles of the limbs and facilitates the alpha, beta, and gamma motoneurons that innervate distal flexor musculature

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

where do the axons in the corticospinal tract originate?

A

1/3 originate in primary motor cortex (area 4)

1/3 arise in the premotor and supplementary motor regions in area 6

1/3 originate in the parietal lobe (areas 3,1,2)

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

together, the areas of cortex that contribute to the corticospinal and corticobulbar pathways are called the :

A

sensorimotor cortex

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

the corticospinal tract passes through the ____ and then ____

A

posterior limb of the internal capsule and the middle of the cerebral peduncle

it then breaks up into bundles in the basilar portion of the pons and finally collects into a discrete bundle to form the pyramid of the medulla

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

the corticospinal tract bears the name the pyramidal tract because of :

A

its passage through the medullary pyramid

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

in the lower level of the medulla, most of the corticospinal tact:

A

crosses (decussates) to the opposite side

termed the level of the motor or pyramidal tract decussation

32
Q

about 90% of the corticospinal tract fibers cross at the level of the pyramidal tract decussation and descend through the SC as the :

A

lateral corticospinal tract

which passes to all SC levels in the lateral funiculus and synapses in the lateral aspects of the laminae IV-VIII

33
Q

the remaining 10% of corticospinal tract fibers that don’t decussate in the medulla descend:

A

in the anterior funiculus of the cervical and upper thoracic cord levels as the Ventral corticospinal tract

doesn’t not extend below the upper thoracic SC

at their individual levels of termination, most fibers in this pathway descussate through the ventral white commissure before they synapse on interneurons and motoneurons of the contralateral side

34
Q

the corticospinal tract fibers that synapse on interneurons in the base of the dorsal horn (IV, V and VI) can influence:

A

local reflex arcs and cells of origin of ascending sensory pathways

through this system, the cerebral cortex can control reflex motor output and can also modify sensory input reaching the brain

35
Q

the cortical neurons that give rise to the corticospinal tracts use:

A

glutamate as a neurotransmitter and excite the neurons on which they synapse

36
Q

the corticospinal tract can exert either __ or ___ effects on motoneurons

A

excitatory

inhibitory

37
Q

excitatory effects result from:

A

direct (monosynaptic) connections with motorneurons

38
Q

inhibitory effects occur through:

A

synaptic connections on inhibitory interneurons

many of the interneuons mediating inhibitory effects use glycine as a neurotransmitter

39
Q

fibers of the coricobulbar tract arise from:

A

neurons in the ventral part of the sensorimotor cortex on the lateral surface of the hemisphere from brodman’s area 8

40
Q

the cranial nerve motor nuclei receive innervation from:

A

both cerebral hemispheres, and in most cases, the muscles they control cannot be contracted voluntarily on one side only

41
Q

a lesion of one cerebral hemisphere results in:

A

weakness primarily on the contralateral side

42
Q

like the corticospinal tract, the corticobulbar tract contains fibers that terminate on:

A

sensory “relay” neurons

43
Q

what is the corticotectal tract?

A

pathway that arises from the cerebral cortical areas in the occipital and inferior parietal lobes and projects to the upper parts of the brain stem to influence extraocular muscle activity

many of these fibers synapse in the superior colliculus, the interstitial nucleus of Cajal, or the nucleus of Darkschewitsch. these nuclei project to the pontine reticular formation and from there through the medial longitudinal fasciculus (MLF) to synapse on the oculomotor, trochlear and abducens nuclei

44
Q

corticotectal fibers make connections in the:

A

deep layers of the superior colliculus with neurons that give rise to the tectospinal tract

axons of these cells cross the midline in the dorsal tegmental decussation and descend through the brain stem ventral to the MLF

45
Q

in the SC, the tectospinal tract becomes incorporated into the:

A

MLF, with which it travels through the ventral funiculus.

46
Q

the tectospinal fibers extend only through the :

A

cervical segments of the SC, where they influence neurons innervating muscles of the neck, including the neurons of the spinal accessory nucleus (CN XI)

47
Q

the corticotectal-tectospinal projections are concerned with:

A

turning movements of the head and eyes, possibly combined with reaching movements of the arm

corticotectal fibers have a greater influence on reflexive than on voluntary eye movments

48
Q

the corticorubral and rubrospinal tracts represent:

A

an indirect route from the cerebral cortext to the SC

49
Q

fibers originating from the same cortical areas that give rise to the corticalspinal tract also form the :

A

corticorubral tract

50
Q

the corticorubral tract projects to the :

A

ipsilateral red nucleus in the tegmentum of the midbrain

51
Q

neurons of the red nucleus give rise to the:

A

rubrospinal tract

which crosses the midline in the central tegmental decussation and descends through the lateral tegmentum of the pons, midbrain and medulla

52
Q

the rubrospinal tract is functionally similar to the:

A

corticospinal tract in that it generally facilitates flexor and inhibits extensor alpha, beta and gamma motoneurons, particularly those innervating the distal parts of the arms

53
Q

the reticular formation consists of :

A

a matrix of nuclei in the core of the brain stem that receives sensory info from numerous systems and interconnects heavily with the cerebellum and the limbic system

54
Q

the reticular formation receives a large input from :

A

corticoreticular fibers which accompany the corticospinal and corticalbulbar fibers

corticoreticular fibers from each hemisphere terminate bilaterally in the brain stem

the corticoreticular system arises from cells outside and within the sensorimotor cortex

55
Q

what are the 2 areas of the reticular formation that send major projections into the SC?

A

1- pontine (medial) reticulospinal tract

2- medullary (lateral) reticulospinal tract

56
Q

the pontine reticular formation gives rise to the:

A

uncrossed pontine (medial) reticulospinal tract

in the medulla and the cervical segments of the SC this pathway travels within the MLF

in the thoracic SC, where the MLF ends, the medial reticulospinal tract continues through the ventral funiculus to all cord levels. its fibers synapse in laminae VII and VIII

57
Q

the pontine tract is mainly excitatory for:

A

extensor alpha motoneurons, particularly those innervating the midline musculature of the body and the proximal parts of the extremities.

it also provides an important input to gamma motoneurons.

through these connections the pontine reticulospinal tract influences posture and locomotion

58
Q

the medullary reticular formation gives rise to the:

A

medullary (lateral) reticulospinal tract

primarily uncrossed but has a small crossed component.

this tract passes to all spinal cord levels in the lateral funiculus immediately anterior to the rubrospinal tract

it synapses in laminae VII and IX

59
Q

the medullary reticulospinal tract conveys:

A

autonomic information from higher levels to the preganglionic sympathetic and parasympathetic neurons to influence respiration, circulation, sweating, shivering and dilation of the pupils as well as the function of the sphincteric muscles of the GI and urinary tracts

60
Q

raphe nuclei

A

constitute a special subgroup of the larger group of nuclei that make up the reticular formation

fibers arising from neurons within the caudal raphe nuclei project to the SC where they influence transmission of incoming sensory signals and motor responsiveness. these fibers pass down the entire length of the SC near the surface of the lateral funiculus and terminate with laminae I, II V and VII

doesn’t evoke movement but depending on the inputs it receives, can produce either general excitatory or general inhibitory effects that greatly influence motoneurons responsiveness to reflex or corticospinal inputs.

thus they function as a gain setting system that determines overall motoneuron responsiveness.

particularly important in modulating the responsiveness of the motor system in different phases of sleep-waking cycles and with changes in emotional state

61
Q

vestibulospinal tracts arise from:

A

neurons in the vestibular nuclei of the medulla

62
Q

what are the 2 vestibulospinal tracts?

A

lateral : extends the entire length of the cord

medial: becomes incorporated into the MLF and ends with the MLF in upper thoracic levels

63
Q

both vestibularspinal tracts pass:

A

into the anterior funiculus and synapse on cells in laminae VII and VIII

64
Q

the lateral vestibulospinal tract evokes:

A

excitatory postsynaptic potentials in extensor motoneurons innervating the neck, back, forelimb and hindlimb muscles

these excitatory postsynaptic potentials are monosynaptic for neck motoneurons and some back and leg motoneurons

stimulation also evokes reciprocal inhibition in flexor motoneurons through disynaptic or polysynaptic connections

65
Q

stimulation of the medial vestibulospinal tract evokes:

A

monosynaptic inhibition and excitation in neck and back motoneurons but does not influence limb motoneurons

66
Q

the vestibulospinal pathways affect:

A

postural adjustments of the body accompanying head movements and the maintenance of postural tone

67
Q

the MLF consists of:

A

a bundle of several tracts in the midline of the brain stem and the ventral funiculus of the SC

68
Q

the descending portion of the MLF in the SC contains:

A

the pontine (medial reticulospinal tract)

the medial vestibulospinal tract

the interstitiospinal tract

the tectospinal tract

69
Q

the MLF modulates :

A

reflex movements of the head and neck in response to visual and vestibular stimuli

70
Q

lateral and ventral corticospinal tracts provide:

A

the capacity for control of finely fractionated movements- independent movements of the fings

71
Q

aside from the lateral and ventral corticospinal tracts the remaining pathways descending from the brain that regulate movement cab be described as 2 general projection systems from the brain stem:

A

lateral and ventromedial sytems

72
Q

the lateral brain stem system consists of:

A

fibers arising in the contralateral magnocellular red nucleus that project to the SC through the rubrospinal tract and ibers from the ventrolateral portion of the contralateral pontine and medullary tegmentum that project through the lateal column of the SC

this pathway terminates in the lateral aspect of the dorsal and ventral horns of the SC

73
Q

like the corticospinal tracts, the lateral brain stem system participates in:

A

the control of fine manipulative, independent movements of the limbs, particularly of the hands and feet and with discrete motor patterns

these pathways generally facilitates the activity of motoneurons projecting to flexor muscles and inhibits the activity of motoneurons projecting to extensors

74
Q

the ventromedial brain stem system terminates in the:

A

ventral and medial aspects of the anterior horn of the SC

75
Q

the ventromedial pathways participate in:

A

maintenance of the erect posture, integrated movements of the body and limbs and progression movements of the limbs

these pathways generally facilitate the activity of motoneurons projecting to extensor muscles and inhibit the activity of motoneurons projecting to flexors.

76
Q

the lateral (medullary) reticulospinal system participates in the:

A

regulation of autonomic motoneurons

77
Q

propriospinal pathways play an essential role in”

A

spinal cord function

Neuro (48 decks)

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