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Flashcards in Motor I, II, and III Deck (64)
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1

Motoneurons innervating axial and proximal muscles are located (laterally/medially) in the ventral horn of the spinal cord.

Medially

2

Motoneurons innervating distal muscles are located (laterally/medially) in the ventral horn of the spinal cord.

Laterally

3

Motoneurons innervating extensor muscles are located (ventral/dorsal) to those innervating flexor muscles.

Ventral

4

(T/F) Interneuron pools in the intermediate gray that innervate motoneurons are segregated in the same way as motoneurons in the ventral horn.

True.

5

(T/F) Descending tracts are located in the white matter adjacent to the relevant motoneuron pools they control.

True.

6

Proprioceptive input to a cortical column arises in the joint (proximal/distal) to the muscle that the column controls.

Distal

7

Cutaneous input to a cortical column arises where?

From a skin region in the path of limb movement that the column controls.

8

Inputs to the cortical columns travel through the ______________ and _____________ thalamic nuclei.

Ventroanterior and ventrolateral thalamic nuclei

9

The standard visuo-motor reflex takes about ___ms.

240ms

10

The standard cortical reflex takes about ___ms.

120ms

11

90% of the corticospinal tract arises in the ____________ and ___________ cortices.

Precentral and postcentral

12

Pathways controlling axial and proximal muscles for use in posture typically undergo (phasic/tonic) innervation.

Tonic

(TPP) = Tonic, Proximal, Posture

13

Pathways controlling distal muscles for use in discrete movements typically undergo (phasic/tonic) innervation.

Phasic

(PDD) = Phasic, Distal, Discrete

14

Muscle tracts that make use of tonic innervation include:

  • Pontine reticulospinal
  • Vestibulospinal
  • Tectospinal

Tonic = Control Postuer (Axial and proximal muscle groups)

15

Muscle tracts that makes use of phasic innervation include:

  • Corticospinal
  • Rubrospinal
  • Medullary reticulospinal

Phasic = Control Discrete Muscle Movement (Distal muscle groups)

16

The lateral corticospinal tract primarily terminates upon (flexor/extensor) interneurons.

Flexor interneurons

17

The rubrospinal tract usually (activates/inhibits) flexors and (activates/inhibits) extensors of the upper body.

  • Activates flexors
  • Inhibits extensors

Massive effect on force (flexor part of emergency control; i.e. grabbing onto tree when you fall)

Acts on alpha motor neurons

18

The medullary reticulospinal tract usually (activates/inhibits) flexors and extensors.

Inhibits flexors
Inhibits extensors

19

(T/F) Upon entering sleep, the medullary reticulospinal tract hyperpolarizes the body's flexor and extensor interneurons. This is a defense mechanism to cause paralysis during sleep and prevent movement during vivid or imaginative dreams.

True.

20

The vestibulospinal tract primarily activates (flexor/extensor) alpha motor neurons and interneurons. It is important in maintaining balance and prevention of injury while falling.

Extensors

21

The pontine reticulospinal tract typically (activates/inhibits) extensor interneurons.

Activates extensors

Helps you stand up

22

The tectospinal tract activates (extensor/flexor) interneurons of the upper cervical areas to track objects on the edges of the field of vision by moving the neck.

Extensor

23

What path do fibers in the corticospinal tract travel after leaving the motor cortices?

  1. Corona radiata
  2. Internal capsule (posterior limb)
  3. Cerebral peduncle (middle third)
  4. Pons
  5. Pyramids
  6. Decussation into lateral and anterior corticospinal tracts

24

Glutamate is (excitatory/inhibitory).

Excitatory

25

Inputs to the striatum (caudate nucleus and putamen) from the cerebral cortices use the neurotransmitter _____________.

Glutamate

26

Inputs to the striatum (caudate nucleus and putamen) from the thalamus use the neurotransmitter ______________.

Glutamate

27

Inputs to the striatum (caudate nucleus and putamen) from the substantia nigra use the neurotransmitter ______________.

Dopamine

28

Inputs to the striatum (caudate nucleus and putamen) from the raphe nucleus use the neurotransmitter _______________.

Serotonin

29

Outputs from the striatum travel to the _________ and _________.

Globus pallidus and substantia nigra

30

The ___________ and __________ function to regulate output from the striatum.

Subthalamic nucleus and external pallidum (of globus pallidus)