Week 4- Motor Pathways Flashcards
Where is the pyramidal tract
Corticospinal tract
(Lateral and anterior)
Where is the extrapyramidal tract
Rubrospinal
Reticulodspinal
Vestibulospinal
Tectospinal
Olivospinal;
Describe cotriocospinal tracts
Modality- voluntary, discrete, skilled movements
Lateral: distal limb musculature-fine movements
Anterior: axial musculature- gross movements
Fibres originate from primary motor cortex, supplementary motor area, pro motor cortex
Pyramidal cells of cortex
Rubrospinal tract (cortico-Rubrospinal) function
Facilitates flexor and inhibits extensor muscles
Axons descend from cortex (cortico rural fibres)
Red nucleus of midbrain
crosses- csuperior colliculus of midbrain, descends controlaterally
lateral spinothalamic tract
1=Dorsal root ganglion
2= substantia gelatinosa. corss over in anterior grey and white matter
3=Ventroposterior lateral nucleus of thalamus
modality= pain + temp
receptors= free nerve endings, nociceptors
What is the relay centre
Thalamus
list all descending tracts
Pyramidal tract
Corticospinal tract (Lateral & Anterior)
Extrapyramidal tracts
Rubrospinal
Reticulospinal
Vestibulospinal
Tectospinal
Olivospinal
whwre do lateral corticospinal tract extend
extends throughout the length of the spinalcord
- Terminate directly or indirectly(through interneurons) on anterior horncells
where is recticular formation
brain stem
recticulopsinal tract
mostly uncrossed.
terminate in LMN
lower motor neuron
function= locomotion and postural control
function and arising of tectospinal tract
Reflex postural movementsin response to visual stimuli
Arises from superior colliculus of midbrain
- Crosses - dorsal tegmental decussation in superior colliculus of MIDBRAIN
- End in anterior grey column (LMN)
vestibulospinal tract origin, corss and termination and function
Originates from vestibular nuclei in medulla
- 2 tracts- medial and lateral VST
- Medial-H&N ext
- Lateral: axial and appendicular ext*
Uncrossed
- Terminate in lamina (LMN)* (Brake system is rubrospinal)
facilitates extensor muscles(antigravity), to maintain posture and balance, inhibits flexors
olivospinal tract function, origin, cross, terminate
Reflex movements arisingfrom proprioceptors
Arise from inferior olivary nucleus in medulla
Crosses over and descends in lateral white column
Terminates at anterior horn cells
Posterior column / Medial lemniscal pathway, modality and receptors
receptor on dorsal root ganglion
nucelus gracilis + cuneatus in the medulla oblongata
thalamus
modality= conscious propriception, vibratory sense, fine touch, discrimiative touch
receptors- pacinian corpsucles , muscle spindle, golgi tendon organ
describe slow pain
Slow pain
* C fibres
* Unmyelinated
* Poorly localized
* Slow conducting
* Substance P
describe fast pain
A fibres𝛿
* Myelinated
* Localized
* Fast conducting
* Glutamate
describe posterolateral tract of lissauer
1st order neuron enters posteriorhorn
- Divides into ascending anddescending branche
- Travel for 1- 2 segments
- Terminate by synapsing with 2ndorder neurons in substantiagelatinosa
Anterior spinothalamic tract modality, receptors and order neurons.
light tuch and pressure
receptors- free nerve endings
1= dorsal root ganglion
2= substantia gelatinosa
3= ventroposterior lateral nucleus of thalamus
Posterior spinocerebellar tract modality + function, receptors and neurons
*Modality: Unconscious proprioception (muscle joint sense)
*Function: Fine coordination of posture and movements of trunk and lower limb
receptors - muscle spindle, golgi tendon
1= dorsal root ganglia
2=Uncrossed
lateral funiculus
medulla oblongata, pons, midbrain
inferior cerebllar peduncle
3= cerebellum
anterior spinocerebellar tract modality + function, receptors and neurons
unconscious proprioception (muscle, joint)
gross coordination of posture and movements of turnk and lower limbs
receptors- muscle spindle, golgi tenbdon organs
1= dorsal root ganglian
2= crossed. controlateral lateral funiculius
medulla oblongata, pons, midbrain
superior cerebellar peduncle
3= cerebellum
cuneocerebellar tract function and 1/2/3 order neuron and function
unconsious propriception for upper limb and upper trunk
1= dorsal root ganglion
2= cuneate nucleus in medulla
posterior external arcuate fibres
UNCROSSED
inferrior cerebllar peduncle
3= cerebellum
Spinoreticular tracts function and 1/2/3 motor neuron
arousal and emotional aspects of somatosensory stimuli
*1 – dorsal root ganglion
2nd order neuron –
Posterior grey column -
Laminae V- VII
Accompanies the spinothalamic pathways
* Fibres ascend in lateral funiculus
* Uncrossed
*3rd order neuron – Reticular nuclei present in the brainstem—further projected to cortex for arousal, hypothalamus and thalamus for emotional behavior
Spinotectal tract function and 1/2/3 motor neuron
*Function – provides afferent information for the spinovisual reflexes and bring aboutthe movement of head and eyes towards source of stimulation
*1st order neuron – dorsal root ganglion
2nd order neuron – (unknown)posterior grey columnSecond order neurons cross and ascend in the anterolateral funiculus
* - Medulla oblongata, pons
*3rd order neuron - Superior colliculus of midbrain
syringomyelia
caviation in gray commisure
destruction of corssing spinothalamic fibres in white commisure
sensory loss
