Central sensory and motor pathways Flashcards
What are the major ascending tracts what neurones do they carry?
Lateral spinothalamic tracts
Dorsal columns
Dorsal spinocerebellar tracts
Carry afferent fibres ie sensory information to the CNS
What structure in the Brian separates the primary motor cortex from the primary sensory cortex?
Central sulcus
separates frontal lobe from parietal lobe
What is either side of the central sulcus?
Precentral gyrus located anteriorly is the primary motor cortex contrains motor map of body
Postcentral gyrus located posteriorly contains the primary sensory cortex and sensory map of the body
What information do the dorsal columns carry and how is this information carried?
Fine touch vibration and proprioceptive information
conveyed up the spinal cord on the same side it enters remains ipsilateral (decussates in the medulla)
What information does the spinothalamic tract carry and how is this information carried?
Pain temperature and crude touch signals immediately decussates to conterlateral side and then ascends the spinal cord
What are conscious and unconscious sensations
Conscious we are directly aware of the sensory information
unconscious we are not directly aware of the sensory information
What is the first stage of spinal sensation (spinothalamic)
primary sensory neruones detect simulus (pesudounipolar morphology)
arrives in dorsal horn then divides in three ways
1 terminates in the dorsal horn of the respective spinal segment
1 travels to the dorsal horn of the spinal segment above and 1 is sent to the dorsal horn of spinal segment below they do this through the posterolateral tract of lissauer
What is the second stage of sensory transmission in the spinal cord? (spinothalamic)
all fibres treated int the same way then crosses the spinal cord under the central canal and then ascend spinothalamic
What is syringomyelia?
Cyst expanse and can coined of the point where axons cross the grey matter under the central canal
can lead to loss of
sensations of pain temperature and crude touch
Can be due to a spinal cord injury very rare
What is the corticospinal or pyramidal descending tract pathway?
What type of efferent control are they concerned with?
Voluntary motor controll
originate in the primary motor cortex and descend through medulla where they decussate to conterlateral side then descend the spinal cord through the lateral and ventral corticospinal tract to cell bodies in the ventral horn of the spinal cord.
Activation or inhibition of motor neurones leading to muscle contraction or relaxation
what are non cortical descending tracts more involved in and where do they orginate?
More in autonomic efferents
originate in the midbrain brainstem pons and medulla
