Spinal Cord and Periphery Flashcards
On the spinal cord, where is the grey and white matter in relation to each other?
Central grey matter and peripheral white matter
Where do axons of sensory fibres enter the spinal cord?
Through the dorsal root into the dorsal horn of grey matter
Where are the cell bodies of motor neurons in the spinal cord?
Ventral horn
What are the 3 columns of white matter in the spinal cord?
Posterior
Lateral
Anterior
What is found in each column of the spinal cord?
Various bundles (tracts) of xons
What kind of tracts are ascending pathways?
Sensory
What kind of tracts are descending pathways?
Motor
What are 3 important tracts of the spinal cord?
Corticospinal/pyramidal tract
Posterior/dorsal column
Lateral spinothalmic tract
What does the corticospinal/pyramidal tract carry?
Motor impulses from motor cortex to skeletal muscles
What does the posterior/dorsal column carry?
Touch, tactile localisation, vibration sense, proprioception
What does the lateral spinothalmic tract carry?
Pain and temperature
Where does the corticopsinal/pyramidal tract begin?
Motor cortex (area 4)
Do corticobulbar fibres go to the ipsilateral or contralateral nuclei?
Contralateral
Where do the corticospinal fibres decussate?
Decussation of pyramids
What are the different corticospinal tracts?
Lateral and anterior corticospinal tract
Do the anterior corticospinal tracts decussate?
No, only the lateral
What does the lateral and anterior corticospinal tracts innervate?
Lateral - limb muscles
Anterior - axial muscles
What are the fibres before anterior/lateral corticospinal fibres called?
Corticobulbar fibres
What are the 2 types of neurons in the corticospinal tract?
Upper motor neuron
Lower motor neuron
What is the site of the lower motor neurons?
Ventral horn
What are the common characteristics of pathways reaching conscious level (ascending spinal tracts)?
There are 3 neurons between peripheral receptor and cortex
Receptor -> first order neuron -> second order neuron -> third order neuron -> contralateral parietal cortex
In ascending spinal tracts, where is the first order neuron?
Dorsal root ganglion