The Spinal Cord and Periphery Flashcards
what are the three columns of white matter?
posterior, lateral & anterior.
what does each column of white matter contain?
various bundles (tracts) of axons.
are ascending pathways sensory or motor?
sensory
are descending pathways sensory or motor?
motor
what are the three important tracts
Corticospinal/ pyramidal tract
Posterior/ dorsal column
Lateral spinothalamic tract
function of Corticospinal/ pyramidal tract
carries motor impulses from motor cortex to skeletal muscles
function of Posterior/ dorsal column
carries touch, tactile localisation, vibration sense, proprioception
function of Lateral spinothalamic tract
pain and temperature
where does the pathway start for CORTICOSPINAL/PYRAMIDAL TRACT
starts from the motor cortex (Area 4)
what are the characteristics of ascending spinal tracts pathways?
There are 3 neurons between peripheral receptor and cortex.
how does the posterior/dorsal column work?
1st order neuron ends by synapsing with the cell body of the 2nd neuron. This is situated in the lower part of the medulla.
2nd order neuron crosses over (decussates) in the medulla.
The third order neuron starts from the thalamus and axons pass through the IC and radiate to the post-central gyrus (Area 2,1,3)
where does the first order neuron enter in the lateral spinothalamic tract?
into the grey matter and ends at the same level.
why do the 2nd order neurons cross over in the lateral spinothalamic tract?
to reach the lateral column and is now called lateral spinothalamic tract
where does the 2nd order neuron end in the lateral spinothalamic tract?
thalamus and 3rd order passes through IC, radiation to reach post-central gyrus
what is a reflex?
involuntary stereotyped pattern of response brought about by a sensory stimulus.
