Motor

Question 1

What does the cortex send to the spinal cord?

Answer 1

Direct and indirect projections
-Corticospinal and corticovulbar/bulbospinal

Question 2

How is movement initiated?

Answer 2

In the basal ganglia which projects to the motor cortex

Question 3

What is movement regulated by?

Answer 3

The cerebellum which projects to the motor cortex

Question 4

What does the cerebral cortex consist of?

Answer 4

Primary motor cortex, premotor cortex, Broca’s area, Frontal eye field

Question 5

Describe the frontal eye field.

Answer 5

Number 8
Voluntary movements of the eyes

Question 6

Describe Broca’s area.

Answer 6

Numbers 44 and 45
One side only- typically the left
motor speech area
Think Broca Broadcasting

Question 7

Describe the premotor cortex.

Answer 7

Anterior to precentral gyrus (6)
Coordinates simultaneous movement of many muscle groups

Question 8

Describe the primary motor cortex.

Answer 8

Precentral gyrus (4) of the frontal lobe
Related to the somatosensory cortex (3,2,1)

Question 9

What region of the brain activates as we think about movement?

Example: When I think about getting up to pee while laying in bed

Answer 9

The supplementary motor

Question 10

WWhat is the purpose of descending motor pathways?

Answer 10

Descending tracts deliver efferent impulses from the brain to the spinal cord

Question 11

What are the two groups of descending tracts?

Answer 11

Direct pathways aka pyramidal tracts
Indirect pathways aka any other tract

Question 12

How many neurons do motor pathways involve? What are they?

Answer 12

Two- One upper in the motor cortex and one lower that is a spinal/cranial nerve motor neuron

Question 12

How many neurons do motor pathways involve? What are they?

Answer 12

Two- One upper in the motor cortex and one lower that is a spinal/cranial nerve motor neuron

Question 13

Where do direct pathways originate?

Answer 13

In the precentral gyri with pyramidal neurons

Question 14

Where are impulses sent in the direct system?

Answer 14

Through the corticospinal tracts and synapse in the anterior horn

Question 15

What activates skeletal muscles?

Answer 15

Stimulation of anterior horn neurons

Question 16

What part of the direct pathway innervates the cranial nerve nuclei

Answer 16

Corticobulbar tracts

Question 17

What does the direct pathway regulate?

Answer 17

Fast and fine skilled movents

Question 18

What does a motor unit consist of?

Answer 18

The efferent branches of the axon of a spinal/cranial motor neurons and all the muscle fibers that it innervates

Question 19

Where does innervation of skeletal muscle take place?

Answer 19

Neuromuscular junction

Question 20

What role does acetylcholine have in the innervation of skeletal muscle?

Answer 20

Acetylcholine is the NT that diffuses across the synaptic cleft

Binds to receptors causing ions to move, depolarization of cell and end plate potential that results in an action potential

Question 21

Which cranial nerve nuclei innervate extraocular muscles?

Answer 21

CN III - Oculomotor
CN VI- Abducens
CN IV - Trochlear

OAT

Question 22

Which cranial nerve nuclei innervate the muscles of mastication (chewing)?

Answer 22

CN V -Trigeminal

Question 23

Which cranial nerve nuclei innervates the muscles of facial expression?

Answer 23

CN VII- Facial

Question 24

Which cranial nerve nuclei innervates the muscles of the tongue?

Answer 24

CN XII- Hypoglossal

Question 25

How does paralysis occur?

Answer 25

Cross sectioning of the spinal cord at any level causes motor and sensory loss in regions inferior to the cut

Question 26

What is paraplegia? Which sections of the spinal cord must be affected for paraplegia to occur?

Answer 26

Paralysis of the legs but not the arms Transection between T1 and L1

Question 27

What is quadriplegia? Which sections of the spinal cord must be affected for quadriplegia to occur?

Answer 27

Paralysis of all limbs from the neck down Transection in the cervical region

Question 28

What is paralysis?

Answer 28

Loss of motor function

Question 29

What is flaccid paralysis?

Answer 29

Severe damage to the ventral root or anterior horn cells Lower motor neuron damage therefore impulses do not reach muscles Results in no voluntary or involuntary control of muscles

Question 30

What is Spastic Paralysis?

Answer 30

Only upper motor neurons of the primary motor cortex are damaged Spinal neurons remain intact and muscles are irregularly stimulated No voluntary control of muscles

Question 31

What does the indirect descending motor system include?

Answer 31

Brain stem, motor nuclei and all motor pathways not part of the pyramidal system Also vestibulospinal, reticulospinal, and tectospinal tracts

Question 32

What is another name for the indirect descending system?

Answer 32

Extrapyramidal system

Question 33

True or false: Motor pathways are complex and multisynaptic?

Answer 33

True

Question 34

What do axial muscles maintain?

Answer 34

Balance and posture

Question 35

What do motor pathways regulate?

Answer 35

Axial muscles muscles controlled coarse movements of the proximal portions of limbs Head neck and eye movement

Question 36

What do reticulospinal tracts do?

Answer 36

Maintain balance

Question 37

What do rubrospinal tracts do?

Answer 37

Control flexor muscles

Question 38

What do the superior colliculi and tectospinal tracts mediate?

Answer 38

Head movements

Question 39

What does the cerebellar cortex do?

Answer 39

Calculates the best way to perform a movement

Question 40

What is the role of the cerebellum?

Answer 40

data reception from the cortex with the intent to initiate voluntary movement

Question 41

What do proprioceptors and visual signals do?

Answer 41

Inform the cerebellum of the body's condition

Question 42

True or false: In cerebellar processing, a blueprint of coordinated movement is sent to the cerebral motor cortex?

Answer 42

True

Question 43

What is the neocerebellum?

Answer 43

The lateral lobes/dentate nucleus connections to and from the cerebral cortex dysmetria and ataxia (Intention tremor)

Question 44

What does the midline cerebellum do?

Answer 44

Responsible for spinal inputs, posture and balance

Question 45

What does the vestibulocerebellum responsible for?

Answer 45

Flocculonodular lobe/fastigial nucleus Vertigo nystagmus

Question 46

What happens in the final common pathway?

Answer 46

Lower motor neurons recieve signals from both direct and indirect upper motor neurons Sum of all inhibitory and excitatory signals determine the final response of the lower motor neuron and skeletal muscles

Question 47

What happens if the cortex or corticospinal tract is damaged?

Answer 47

The normal plantar flexion response to stroking the sole is replaced by dorsiflexion *Note the dorsiflexion response is only appropriate in infants 0-1 years old

Question 48

What can result after a spinal cord injury?

Answer 48

Muscle spasms- Normal flow of signals is disrupted and the message does not reach he brain instead they are sent back to the motor cells in the spinal cord