Ascending an Descneding pathways

Question 1

what type of neurons does the ventral column contain

Answer 1

motor

Question 2

what type of neurons does the dorsal column contain

Answer 2

sensory

Question 3

what are the ascending pathways

Answer 3

SENSORY
dorsal column/medial leminiscus system
spinothalamic tract

Question 4

what are the descending pathways

Answer 4

MOTOR

pyramidial and extra-pyramidial tracts

Question 5

what are the extra-pyramidial tracts

Answer 5

tectospinal tract
reticulospinal tract
vestibulospinal tract

Question 6

what sensory modalities are controlled by dorsal column medial leminiscus tract

Answer 6

fine touch

proprioception

Question 7

what sensory modalities are controlled by spinothalamic tract

Answer 7

pain, temperature and deep pressure

Question 8

how do first order axons enter spinal cord for DCML

Answer 8

through dorsal root and travel up dorsal column

Question 9

where do first order neurons terminate in DCML tract

Answer 9

medulla oblongata - nucleus gracilis and nucleus cutaneous

Question 10

where do fibres for DCML cross the midline and where do they go

Answer 10

medulla oblongata - 2nd order neurons

travel up medial leminiscus tract (pons)

Question 11

what are 2nd order neurons in DCML called

Answer 11

internal arcuate fibres

Question 12

where do 2nd order neurons from DMCL terminate

Answer 12

ventral posterolateral thalamus

Question 13

where do 3rd order DCML project to

Answer 13

parietal cortex in somatotopic arrangement

Question 14

how do PNS sensory fibres enter spinothalamic tract

Answer 14

through dorsal root to dorsal column

terminate in posterior aspect of dorsal horn (substantia gelatinosa)

Question 15

what happens to 2nd order neurons in spinothalamic tract

Answer 15

they decussate in spinal cord (cross midline)
travel up spinothalamic tract (anterior column)
then through lateral/spinal leminiscus (pons)
terminate at thalamus (posterolateral nucleus)

Question 16

where do 3rd order neurons in spinothalamic tract project to

Answer 16

ipsilateral primary sensory cortex

Question 17

what are the function of the pyramidial tracts

Answer 17

voluntary movement of musculature of face and body

Question 18

what are the function of extra-pyramidial tracts

Answer 18

involuntary control of all musculature:
posture
balance
tone 
locomotion

Question 19

where do pyramidial tracts originate

Answer 19

cerebral cortex

Question 20

where do extra-pyramidial tracts originate

Answer 20

brain stem

Question 21

where are upper motor neurons found

Answer 21

CNS
cell body in brain stem or cerebral cortex
axons remain in CNS

Question 22

what are the 2 pyramidial tracts

Answer 22

corticospinal

corticobulbar

Question 23

where do fibres of corticospinal tract originate from and travel to

Answer 23

originate from pre-motor cortex, primary motor cortex and somatosensory area
travel through internal capsule

Question 24

where is internal capsule

Answer 24

between basal ganglia and thalamus

Question 25

what is internal capsule susceptible to and what is the clinical relevance of this

Answer 25

compression from haemorrhagic bleed | may cause lesion of descending pathway

Question 26

where does the corticospinal tract divide into 2, and what are the 2 divisions called

Answer 26

medulla | lateral and anterior

Question 27

what happens to lateral corticospinal tract

Answer 27

decussates in medulla (crosses midline) descends in spinal cord terminating in ventral horn LMN supplies muscles of body

Question 28

what happens to anterior corticospinal tract

Answer 28

remains ipsilateral when travelling down spinal cord | decussate (cross midline) and terminate in ventral horn of CERVICAL and UPPER THORACIC segments

Question 29

where do upper motor neurons of corticobulbar tract terminate

Answer 29

on motor fibres of cranial nerves

Question 30

from the extra-pyramidial tracts, which one does decussate (cross midline)

Answer 30

tectospinal

Question 31

where does tectospinal originate

Answer 31

midbrain - superior colliculus

Question 32

what does superior colliculus receive input from

Answer 32

optic nerve

Question 33

what is the function of the tectospinal tract

Answer 33

control movements of head and neck in relation to visual stimulus

Question 34

where do UMN from tectospinal tract decussate and terminate

Answer 34

decussate in midbrain | terminate in cervical segment of spinal cord

Question 35

where does vestibulospinal tract originate

Answer 35

vestibular nuclei of pons and medulla

Question 36

where do vestibular nuclei receive input from

Answer 36

organs of balance

Question 37

what is the function of vestibulospinal tract

Answer 37

controls anti-gravity muscles to maintain posture and balance

Question 38

what are the anti gravity muscles

Answer 38

flexors of arms | extensors of legs

Question 39

what are the two reticulospinal tracts and where do they originate

Answer 39

medial - pons | lateral - medulla

Question 40

function of medial reticulospinal tract

Answer 40

facilitates voluntary movements | increases muscle tone

Question 41

function of lateral reticulospinal tract

Answer 41

inhibits voluntary movements | decreases muscle tone