Descending Tracts

Question 1

what are descending tracts

Answer 1

Pathways to the spinal cord from cortex and brainstem

The brain “answers” back

Question 2

what are the pathways fro motor control

Answer 2

final common path t alpha/gamma motor neurones
spinal cord contains central pattern generators
motor output of spinal cord controlled by higher centre in cortex and brainstem

Question 3

what do alpha and gamma motor neurones control

Answer 3

alpha - contractile muscle fibres

gamma- spindle function

Question 4

what si path from cortex t sp cord

Answer 4

corticospianl

Question 5

what is the path from midbrain to sp cord

Answer 5

tectospinal

Question 6

what is the path from pons to sp cord

Answer 6

reticulospinal

Question 7

what is the path from medulla to sp cord

Answer 7

vestibulospinal

Question 8

where about are descending tracts

Answer 8

lateral and ventral columns

Question 9

what are in the lateral columns mostly

Answer 9

corticospinal

Question 10

what are in brain stem tracts ventral columns

Answer 10

tectojpinla, reticulospinal, vestibulospinal

Question 11

where is info usually fed in sp cord

Answer 11

into ventral horn

Question 12

what is the route of the cortiospinal trcts

Answer 12

pyramidal cells 
motorcortex
internal capsule
cerebral peduncles 
split tract 
pyramids
later corticospinal tract

Question 13

what does corticospinal tract control

Answer 13

fine distal flexors

Question 14

what does corticospinal tract consist of

Answer 14

50% primary CTX
50% SMA somatosensory
3% Betz cells
single neuron

Question 15

what happens to 85% of neurons and where

Answer 15

crosses sides between medulla and spinal cord

Question 16

what ar basal ganglia

Answer 16

series of grey matter structures in brain

Question 17

what portion of the peduncle contains corticospinal tract

Answer 17

middel 3rd segment

cortex to BS

Question 18

what ar the other two segments of the midbrain peduncle

Answer 18

frontopontine and temporoontien

Question 19

where does the corticospinal tract spot into fibres

Answer 19

in pons

Question 20

where des the cirticospinal that go thro when at the medulla

Answer 20

pyramids - pyramidal tract

Question 21

what is the smooth bit across the medulla

Answer 21

where 85% cross over called decussation of pyramids

Question 22

what happens to the corticopinal tract in a stroke or cerebrovascular accident

Answer 22

• lesion
• internal capsule - bleeding
• degeneration of corticospial tract
• effects on app side of body
• muscle rigidity and hyperreflctive
• upper motor neuron lesion

Question 23

hat does corticospinal tract do

Answer 23

distal flexors

fine movements

Question 24

what does reticulospinal tract do

Answer 24

lateral fine movement
medial proximal limb
repetitive movements
locomotion

Question 25

what doe vestibulospinal tract do

Answer 25

lateral
proximal extensors
balance

Question 26

what does tectospinal tract do

Answer 26

relations to light
auditory stimulus
controls neck region

Question 27

where are the motor association areas

Answer 27

primary motor cortex - pre central gyrus

supplementary (repetitive moves)

premotor cortex (posture, locomotion, planning)

central sulcus (forma nd plan moves)

Question 28

what happens to control the more neurons assc with it

Answer 28

finer control from pre central gyrus think homunculus

Question 29

what is the corticobulbar tract

Answer 29

similar function to corticospinal but supplies motor inv to nuclei serving cranial nerves 3/4/5/6/7/9/10/11/12

Question 30

what are the summary of assc features of motor control

Answer 30

motor cortex 
sp cord 
brainstem 
basal ganglia 
cerebellum 
thalamus