General Sensory and Motor Systems Flashcards
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What is the function of the “Primary Neuron” that is part of the Conscious Sensory Pathway.
PSEUDOUNIPOLAR neuron whose cell body (soma) is located in a spinal ganglion
Dendrites are with a Peripheral Nerve
As it comes into the Spinal Cord, it is going to SPLIT and either ASCEND or DESCEND
Axon is going to terminate on Secondary Neuron
What is the function of the “Secondary Neuron” that is part of the Conscious Sensory Pathway.
Located in the spinal cord (pain and temperature pathway) or in the medulla (proprioceptive pathway)
- ALWAYS decussates and ascends as a lemniscus
- Terminates upon a tertiary neuron in the dorsal thalamus
- -* Sends collateral fibers to the reticular formation (RF) and tectum
What is the function of the “Tertiary Neuron” that is part of the Conscious Sensory Pathway.
SOMA of a tertiary neuron is located in a specific nucleus of the dorsal thalamus
- Tertiary axon projects to the primary somesthetic cortex via the thalamic radiations (thalamocortical fibers) of the internal capsule and corona radiata.
What is the function of the “Primary Somesthetic Cortex” that is part of the Conscious Sensory Pathway.
Plays role in the perception and discrimination of sensory stimuli
What is the function of the “Association Cortex” that is part of the Conscious Sensory Pathway.
Involved in the integration, modification and interpretation of sensory information.
A lesion in a Lemniscus will result in what type of Deficit?
CONTRALATERAL Deficit Patterns!
List the FIVE common features that are part of the Conscious Sensory Pathway.
- Primary Neuron
- Secondary Neuron
- Tertiary Neuron
- Primary Somesthetic Cortex
- Association Cortex
Describe the Gamma Efferent Pathway.
Controls Muscles Tone and Proprioceptive Input to the CNS
Path: Ventral Root of Spinal Nerve –> Intrafusal Fibers encapsulated in the Neuromuscular Spindles
Role: Make sure that the muscles are NOT STRETCHED too far! (Activated when you stretch your muscles)
*** Anxiety has tighten your spindles!
Hypertonia and Hypotonia are going to be a result in the deficiency of which system?
Differentiate between Hypertonia and Hypotonia.
Gamma Motor Reflex System!
Hypertonia: INCREASE in stretch with the Gamma Efferent Fibers
Hypotonia: DECREASE in stretch with the Gamma Efferent Fibers
**** Not good to stretch before you perform a highly precise physical activity because these fibers are going to not be as ACTIVE and your Proprioception is going to be diminished!
Describe the different functions and locations for the Sensory Nuclei of the Spinal Cord.
Pain and Temperature Pathway: Substantia Gelatinosa (–> Lateral Spinothalamic Tract) and Nucleus Proprius (–> Fasciculus Proprius)
Unconscious proprioceptive Pathway: Nucleus Dorsalis (–> Dorsal Spinocerebellar Tract)
Visceral Sensory Integration and Reflex Center: Visceral Afferent Nucleus (–> Intermediolateral gray, ventral horn, and hypothalamus via the fasciculus proprius (RF))
Sensorimotor integration center: Intermediate Gray (–> Ventral Horn)
List the Various Motor Nuclei associated with the Spinal Cord.
Differentiate between the Medial and Lateral Divisions of the Dorsal Root in the Spinal Cord.
Medial Division: Enter the POSTERIOR Column and convey Proprioception, 2-point Tactile Discrimination, and Vibratory information
Lateral Division: Enter the DORSOLATERAL FASCICULUS of LISSAUR and convey Pain and Temperature information
Describe what will happen if you have lesion of the Dorsal Root.
- Lesions of a dorsal root result in anesthesia of the corresponding sensory dermatome.
- The epicritic pain fibers are compromised in the meningovascular infection associated with tabes dorsalis
- Atonic Bladder (S2-4)
Differentiate between the TWO types of fibers in the Posterior Column.
- Long Ascending Fibers: Fasciculus Gracilis and Fasciculus Cuneatus (Proprioceptive and 2-point tactile to the Lower and Upper Extremities Respectively)
- Short Ascending Fibers: Part of the Ventral Spinothalamic Pathway (Passive Touch and Pressure information)
