Spinal Chord and the Perhiphery Flashcards
What is at the center of the spinal chord?
central canal (CSF)
Motor second order type?
multipolar - lots of dendrites around the cell body and one long axon
Where are secondary motor neurons cell bodies?
In the ventral horn
How does naming work in tracts?
from and to (usually)
….. spinal is ascending or descending?
Descending
Spino……. = what type of tract?
Ascending
What is in the corticospinal /pyramidal tract? Where does it take impulses to/from and where is it in the spinal chord?
It takes impulses from brain to the skeletal muscles (motor tract). It is found just laterally to the middle of the spinal chord (in the white matter though (duh))
Posterior/dorsal column carries what and where is it in the chord?
Carries touch, tactile localisation, vibration and proprioception (general sensory) information from the body to the brain. It is found directly posterior to the spinal chord.
Lateral spinothalamic tract, carries what and is found where?
Found anteriolateral to the H, just infront of the corticospinal tract. It carries pain/temperature sensory information.
What area is the pre central gyrus?
Area 4
What type of fibres from area 4
Projection
Internal capsule blood supply
MMA
What tract is used i the motor?
Corticospinal/pyramidal tract
What is the pathway of the corticospinal/pyramidal tract?
Primary motor cortex (area 4) -> through posterior limb of the internal capsule ->
Motor fibres for head and neck:
-head off in corticobulbar tracts to find the respective cranial nerve nuclei from the brainstem (eg for occulormotor/facial etc)
Motor fibres for the rest of the body:
-through cerebellar peduncle (in the crus cerebri) (midbain)
-anteriorly (but spread out) down the pons
-throught he pyramids, dessucate at the bottom of the pyramids and enter into the corticospinal/pyramidal tract. Exit at set spinal level and synapses with second order neuron in anterior horn of spinal chord.
Brachial plexus
C5-T1
Sacral segments from?
L4/5 - S2/3
Where does te corticospinal tract dessucate?
Medulla (bottom of the pyramids)
What does the dorsal coloumn carry (4)?
Vibration, proprioception, fine touch, tactile localisation
What is the path of the posterior dorsal column?
From the impulse, though the pseudounipolar 1st order neuron, dorsal horn, dorsal column, medulla (gracile and cuneate nucleii), synapses with second order neuron, decussates in the medulla, becomes the medial lemniscus (looks like pause button in the medulla), through the horrizontal – in the pons and the horn like things in the mid brain., heads up to the VPL nucleus in the Thalamus, synapses and 3rd order neuron to the post-central gyrus (Area 1,2,3)
Where are the synapses of tehe posterio/dorasl column
1st synapse is in the gracile and cuneate nucleii in the medulla, second synapse is in the VPL nucleus in the thalamus
What is the pathway of the lateral spinothalamic tract?
-synapses in the dorsal horn of the spinal chord
-second order neuron goes to other side of the spinal chord at the level of entry of the spinal chord
-heads up the lateral thalamic tract, all the way to the VPL nucleus of thalamus
-synapses with third order neuron which then takes it to the respective part in the post central gyrus.
Where are the synapses of the lateral spinothalamic tract?
Spinal chord (AND DECUSSATES at that level)
VPL nucleus of the thalamus
Where does the lateral spinothalmic tract cross over?
AT THE LEVEL OF THE SPINAL CHORD!!!!
What is the stretch reflex? Give an example of where? Is it mono or poly synamptic?
Monosynaptic
eg patellar tendon reflex.
-tnedon stretched
-intrafusal muscle fibres stimulated
-sensory neuron activated
-monosynaptic reflex arc ->muscle contraction
-polysynaptic reflex arc -> inhibitory interneuron -> reciprocal innervation of hamstring
