Spinal column & Autonomic nervous system Flashcards
Describe the distribution of white and grey matter in the brain.
White on the inside
Grey on the outside
Describe the distribution of white and grey matter in the spinal cord.
White on the outside
Grey on the inside
Equivalent word for dorsal?
Posterior
Equivalent word for ventral?
Anterior
What part of the spinal cord has a lateral horn?
T1 - L2
What does the dorsal column - medial leminiscus pathway convey?
Fine touch and proprioception
Sensory
What does the spinothalamic tract convey?
Pain, temperature and crude touch
Sensory
What does the corticospinal tract convey?
Axial and limb movement
Motor
At what level does dessucation occur in the dorsal column - medial leminiscus pathway?
At the medulla
At what level does dessucation occur in the spinothalamic tract?
1-2 levels above entry to spinal cord
At what level does dessucation occur in the corticospinal tract?
For limb fibres: medulla
For axial fibres: level of exit from spinal cord
What is the destination of the neurons in the lateral corticospinal tract?
Limb muscles
What is the destination of the neurons in the anterior corticospinal tract?
Axial muscles
Briefly describe the journey of the dorsal column - medial leminiscus pathway beginning in the lower limb.
Lower limb > dorsal root ganglion > Spinal cord - Gracile nucleus > up to medulla > decussates > up to thalamus > ventral posterolateral nucleus of thalamus > post central gyrus
Briefly describe the journey of the dorsal column - medial leminiscus pathway beginning in the upper limb.
Upper limb > dorsal root ganglion > Spinal cord - Cuneate nucleus > up to medulla > decussates > up to thalamus > ventral posterolateral nucleus of thalamus > post central gyrus
Briefly describe the journey of the spinothalamic tract.
Nerve endings/receptors in body > dorsal root ganglion > Spinal cord - Lissauer’s fasciculus > up 1 or 2 levels > dorsal horn of grey matter - substantia gelatinosa or nucleus proprius > decussates at anterior white commissure > ascends via spinothalamic fasciculus > thalamus > post-central gyrus
Briefly describe the journey of the corticospinal tract going to the limb muscles.
Pre-central gyrus > through internal capsule to midbrain > decussates at medulla (75-90% fibres) > down spinal cord via lateral corticospinal tract > anterior horn cells > neuron to limb muscles
Briefly describe the journey of the corticospinal tract going to the axial muscles.
Pre-central gyrus > through internal capsule to midbrain > down spinal cord via anterior corticospinal tract > decussates at anterior white commissure > anterior horn cells > neuron to axial muscles
Which are the upper motor neurons in the corticospinal tract?
From brain to anterior horn cell
Which are the lower motor neurons in the corticospinal tract?
From anterior horn cell to muscles
What is Brown-Sequard syndrome?
Unilateral lesion of the spinal cord
Ipsilateral weakness below lesion (corticospinal tract)
Ipsilateral loss of touch sensation and proprioception (DC-ML)
Contralateral loss of pain and temperature sensation (spinothalamic tract)
In Brown-Sequard syndrome, why is the weakness and loss of touch sensation & proprioception one the same side?
Because these spinal tracts (DC-ML and corticospinal) do not decussate until the medulla.
In Brown-Sequard syndrome, why is the loss of pain and temperature sensation on the other side?
Because the spinothalamic tract decussates 1-2 levels above the nerve’s entry to the spinal cord.
What does the autonomic nervous system consist of?
Sympathetic & parasympathetic
and enteric
Does the autonomic nervous system require conscious thought to function?
No!
What structures does the autonomic nervous system innervate?
Smooth muscle, cardiac muscle and glands
Difference between parasympathetic and sympathetic?
Para - rest & digest
Symp - fight or flight
What nerves make up the parasympathetic nervous system?
Cranial nerves 3, 7, 9 & 10
and S2-S4
What nerves make up the sympathetic nervous system?
T1 - L1
What does the enteric nervous system do?
Co-ordinates GI function
