neuro cortex - spine Flashcards
when does the spinal cord terminate
L1/L2
what does the dorsal posterior horn recieve?
somatosensory information
what does the ventral anterior horn contain?
motor neurones for the innervation of muslces
what does the lateral horn contain?
autonomic neurones (sympathetic system T1-L2)
what is DCML responsible for?
fine touch, pressure and vibration
in the DCML pathway, where do the primary sensory fibres travel and synapse?
via the posterior root ganglion, travel up the spinal cord and synapse with secondary neurones in. the medulla (then nucleus cuneatus or gracillis)
where do fibres decussate in the DCML pathway?
medial leminiscus
what is the spinothalamic tract responsible for?
pain and temperature
what is the spinothalamic pathway?
the primary sensory axons enter the spinal cord via the posterior root ganglion then travel upwards for one or two segments at the periphery of the spinal cord through the tract of Lissuaer to synapse in the dorsal horn
they then cross to the contralateral side of the spinal cord to ascend and synapse in the thalamus
sensory signals are then related from the thalamus to the ipsilateral somatosenosry cortex
what is the function of the spinocerebellar pathway?
provides unconcious proprioceptive info to the cerebellum, in order to coordinate posture and the movement of the lower and upper limb musculature
what are the 3 types of spinocerebellar pathways?
dorsal/posterior spinocerebellar
cuneocerebellar
ventral / anterior spinocerebellar
what is the dorsal/posterior spinocerebellar pathway?
it carries unconcious proprioceptive info form muscle spindles from the lower limbs and synapses in the dorsal nucleus of clarke
secondary neuron fibres then ascend to the ipsilateral cerebellum
what is the cuneocerebellar pathway?
it carries unconcious proprioceptive info from the upper limbs to the ipsilateral cerebellum
what is the ventral / anterior spinocerebellar pathway?
carries unconious proprioceptive info (golgi tendon organs mainly) from the lower limbs then decussate twice to reach the ipsilateral cerebellum
does the spinocerebellar tract decussate?
no
does the spinothalamic tract deccusate?
yes
does the DCLM tract deccusate?
yes
what are the pyramidal corticospinal tracts responsible for?
voluntary movements
what is the pathway for the corticospinal tracts?
originates from the motor cortex (precentral gyrus) and travels down to the pyramid of the medulla
majority of fibres decussate at the pyramid of the medulla and descend via the lateral corticospinal tract to supply distal extremities
the minority undecussates fibres travel down via the nateiror corticospinal tract and then wehn they reach the required destination they decussate at that level via the anterior white comissure (they fibres supply proximal and axial muscles)
in the corticospinal pathway, which fibres supply the distal muscles?
those which travel via the lateral corticospinal tract
what is the function of the corticobulbar tracts?
the contain the upper motor neurones and cranial nerves, to provide innervation of the face, head and neck
what is the rule about innervation and the exception for the corticobulbar tract?
they innervate cranial motor nuclei bilaterally
- but hypoglossal nuclei and lower facial nuclei are innervated contralaterally only
what is the clinical significance around the innervation of the facial nerve? - facial palsy
an upper motor lesion affecting the facial nerve causes paralysis of the lower half of one side of the face only and the forehead muscles remain unaffected (this is called facial palsy)
what is the clinical significance around the innervation of the facial nerve? - bell’s palsy
a lower motor neurone lesions would cause a paralysis of the ipsilateral one-half of the face including the forehead
what are the 4 extra-pyramidal tracts?
vesibulospinal
reticulospinal
rubrospinal
tecto-spinal
what does the vestibulospinal tract control?
balance and posture by innervating anti-gravity mucsles (exetensors for leg and flexors for arms)
where does the vestibulospinal tract originate from?
the vestibular nucleus in the pons
what does the reticulospinal tract control?
pontine - faciculates voluntary / reflex responses and increases tone
medullary - inhibits voluntary / reflex and decreases tone
where does the reticulospinal tract originate from?
from the reticular formation in the medulla and pons
where does the rubrospinal tract originate from
the red nucleus in the midbrain
what does the rubrospinal tract coordinate?
excites flexor muscles and inhibits extensor muscles of the upper body
what is the innervation and nerve of the knee reflex?
L3/4 + femoral
what is the innervation and nerve of the biceps reflex?
c5 / C6 + musculocutaneous