129: Tracts of the spinal cord Flashcards
Main ascending tracts
spinothalamic and dorsal column
main descending tracts
corticospinal tract and autonomic pathways ( bladder, bowel, sexual function)
what does the dorsal column relay?
proprioception, light touch and vibration
what does the lateral corticospinal tract relay?
motor
what do the lateral spinalthalamic tracts relay?
pain and temperature
in the dorsal column where do the fasciculus gracilis relay information from?
the upper limbs
in the dorsal column where do the fasciculus cuneatus really information from?
the lower limbs
where does the corticospinal tract decussate?
at the caudal medulla (ventral surface)
where does the spinothalamic tract desucate?
at the level it enters the spine
Where does the dorsal column decussate?
medulla nucleus
definition: mylo
spinal cord
definition: radiculo
nerve root
definition: neuro
peripheral nerve
definition: myo
muscle
Pattern of weakness in upper motor neurone disease?
extensors weaker than flexors in the arms, flexers weaker than extensors in the legs
where does the spinothalamic pathway synapse?
thalamus
where does the dorsal column synapse?
thalamus
where edoes the corticospinal tract synapse?
anterior horn of spinal cord with the motor neurones.
recurrent inhibition is controlled by?
Renshaw cells - via glycine
the inverse myotatic reflex is controlled by?
golgi tendon ( inhibits muscle contraction, drop heavy things)
stretch of a muscle spindle activates which sensory neurone?
1a afferent (myotatic reflex)
stretch of a golgi tendon activates which sensory neurone?
1b afferent
what do gamma motor neurones do?
cause contraction of the spindle to regenerate tension
what do alpha motor neurones do?
cause muscle contraction
what does a lower motor neurone do?
innervate muscle
what does an upper motor neurone do?
innervate lower motor neurons
classic lower motor neurone lesion signs
hyporeflexia, fasiculations, muscle atrophy, denervation
classic upper motor neurone signs
paralysis, babinski, tonus, spasticity, hyper reflexia (UMN dampen down reflex response).
what is brown-sequad syndrome?
loss of one half of the spinal cord - ipsilateral proprioception and motor loss (dorsal and corticospinal cross at medulla), contralateral pain and temperature loss (cross at site of entry)
