Somatic motor systems wk4

Question 1

What are the 2 motor neurons

Answer 1

Upper Motor neuron (red); Lower Motor Neuron (black)

Question 2

Somatic motor system is

Answer 2

voluntary skeletal muscle mmt

Question 3

Coordinated movements also rely on inputs from

Answer 3

brainstem regions (posture & navigational); cerebellum (error correction); basal ganglia (refinement of movement plans)

Question 4

What are defining features of UMN?

Answer 4

Lies within the CNS; pathway to LMN may involve more UMN (interneurons); UMN excitation (for excitation or inhibition of LMN)

Question 5

Pyramidal tract is referred to that because of

Answer 5

pyramidal neurons

Question 6

White matter tract passes

Answer 6

via the internal capsule

Question 7

UMN send projections to brianstem/spinal cord

Answer 7

via corticospinal (corticobulbar) tract

Question 8

What are defining features of LMNs

Answer 8

-LMNS always causes muscle contraction (skeletal muscl inn.)
-Nerve cell body is in a somatic motor nucl of brainstem or spinal cord
-axon projects into PNS via cranial/spinal nerves

Question 9

UMN travels into

Answer 9

medulla (pyramidal decuss); innervates LMN and then it aactivates the distal limb muscles (skilled movements)

Question 10

Primary motor cortex

Answer 10

• Originates from precentral gyrus of cortex
• Voluntary skeletal mucle mmts
  Medial (lower limbs) & lateral (face)

Question 11

Fine movement

Answer 11

greater cortical area

Question 11

Lateral corticospinal controls

Answer 11

movement of limbs and decussates in medulla

Question 12

Anterior corticospinal controls

Answer 12

movements of trunk & axial muscles and decussates at the level of termination

Question 13

Corticospinal tract (motor cortex to spine) is responsible for

Answer 13

voluntary motor control and also projects to basal ganglia and brainstem nuclei

Question 14

Hypoglossal nerve (cranial 12) innervates

Answer 14

tongue muscle

Question 15

Reticulospinal tract

Answer 15

maintining posture and tone in response to mmt

Question 16

Vestibulospinal tract

Answer 16

maintaining posture and balance in response to mmt

Question 17

Tectospinal tract (or. from tecto - midbrain)

Answer 17

head and neck mmt in response to auditory and visual info

Question 18

Rubrospinal tract

Answer 18

control of arm and wrist mmts

Question 19

Lateral pathway (UM in brainstem/midbrain) contains

Answer 19

red nucleus + rubrospinal tract (ends to spinal ventral horn - info to control wrist)

Question 20

Medial pathways are

Answer 20

unconscious but noti involuntary

Question 21

Vestibulospinal tract will be

Answer 21

activated to carry info concerning position of head to the spinal cord

Question 22

In medial pathway (tectospinal tract), we have

Answer 22

inferior (auditory) and superior (visual) coliculi

Question 23

If the lesion of spinal cord affects dorsal horn

Answer 23

there will be a loss of sensory input - touch, pressure/pain/temperature sensations,

Question 24

If the lesion of spinal cord affects the ventral horn,

Answer 24

there will be a loss of LMN and motor output

Question 25

Viral disease -> LMN degeneration ->

Answer 25

widespread paralysis

Question 26

UMN dysfunction (stroke)

Answer 26

leads to degeneration of brain tissue either ischaemic or haemmorphagic

Question 26

Features of strokes include

Answer 26

• contralateral if lesion above medulla
• ipsilateral if lesion below medulla
  -muscle tone increases (=spasticity)
  -muscle atrophy limited as muscle cells still innervated

Question 27

Dorsal horn lesion

Answer 27

loss of sensory input

Question 28

Ventral horn lesion

Answer 28

loss of LMNs & motor output