General Sensory And Motor Systems - 4/19 Stephens Flashcards
In the conscious sensory pathway where is the secondary neuron located?
What does it always do?
Terminates where?
Where does it send collateral fibers?
Spinal cord (pain/temp) or medulla (proprio)
Decussates and ascends as a lemniscus
Terminates upon tertiary neuron or dorsal thalamus
RF or rectus
In the conscious sensory pathway where is the soma of a tertiary neuron located?
Where does it project to?
Via what?
Specific nucleus of the dorsal thalamus
Primary somesthetic cortex via the thalamic radiations of in the internal capsule and corona Radiata
What does the primary somesthetic cortex play a role in?
Perception and discrimination of sensory stimuli
What is the association cortex involved in?
Integration, modification and interpretation of sensory information
From the primary neuron where does the secondary neuron synapse in the pain/temp pathway?
How does it travel?
Substantia Gelatinosa
Dorsolateral Fasciculus of Lissauer
From the secondary neuron, where does the tertiary neuron synapse in the pain/temp pathway?
Travels via what?
Decussates where?
Ventral Posterior Lateral Nucleus (VPLN)
Lateral Spinothalamic Tract then to the Spinal Lemniscus @ the brainstem
Anterior white commissure
After synapsing in the VPLN, where does the pain/temp pathway finally reach?
How does it get there?
Primary somesthetic cortex
Posterior limb of the internal capsule
From the primary neuron (in the spinal ganglion) where does the secondary neuron synapse in the proprioception/2pt pathway?
How does it travel?
Nucleus Gracilis (lower limb) Nucleus Cuneatus (upper limb)
Fasciculus Gracilis (lower) Fasciculus Cuneatus (upper)
From the secondary neuron, where does the tertiary neuron synapse in the proprioception/2pt pathway?
Travels via what?
Decussates where?
Ventral Posterior Lateral Nucleus (VPLN)
Medial Lemniscus
Thalamus
After synapsing in the VPLN, where does the proprioception/2pt pathway finally reach?
How does it get there?
Primary Somesthetic cortex
Posterior limb of internal capsule
From the primary neuron (in the spinal ganglion) where does the secondary neuron synapse in the crude tactile pathway?
How does it travel?
Nucleus Proprius Intermediate Gray
Short Ascending fibers in posterior columns
From the secondary neuron, where does the tertiary neuron synapse in the crude tactile pathway?
Travels via what?
Finally reaches what?
VPLN
VSTT
Primary somesthetic cortex
What do lower motor neurons innervate?
Where are their cell bodies located?
What 2 types are there?
Striated muscle
Craniospinal motor nuclei
Alpha and gamma
What do alpha motor neurons innervate?
Gamma?
Extrafusal or skeletal muscle fibers
Intrafusal fibers that form part of proprioceptive neuromuscular spindles
Activating gamma motor neurons will increase what?
Muscle tension and TONE
Nuclei that innervate branchiomeric muscles are what type?
Myotomic?
SVE
GSE
Poliomyelitis involves what neurons? Located where?
Clinical symptoms?
Prognosis/result?
Motor neurons of ventral horns (LMN) and cranial nerve motor nuclei
Inflammation, vasodilation, edema
Nonparalytic or paralytic
The corticospinal pathway arises from what cortex and gyrus?
What does it descend through?
Primary motor cortex and pre central gyrus
Descends through corona Radiata, posterior limb of internal capsule, cerebral peduncle so (mid 3/5), pons and upper medulla
In the lower medulla, 85-90% of the corticospinal fibers decussate where?
Form what?
Remainder form what?
Pyramidal decussation
Form the lateral corticospinal tract (LCST)
Remainder continue as the anterior corticospinal tract (ACST)
Most of the fibers from the LCST distribute to where?
Cervical (55%) and lumbosacral (25%) enlargements
Unilateral lesions of the LCST result in what?
Ipsilateral paralysis of the distal limb musculature innervated by those spinal segments below the level of the lesion
What is defined as abnormal passive resistance to movement in all directions?
Rigidity
What is defined as abnormal, passive resistance to movement in one direction?
Spasticity
Usually due to hypersensitivity of LMN pools
What clinical region is contained in the posterior columns of the spinal cord?
Proprioception
2-pt tactile discrimination
