motor and sensory pathway Flashcards
What is Lissauer’s tract?
A structure located in the spinal cord that carries pain information.
It is associated with the dorsolateral fasciculus and is found close to the entrance of the posterior nerve roots.
Where do the neurons from Lissauer’s tract synapse?
In the substantia gelatinosa or nucleus proprius.
These are locations in the spinal cord where pain information is processed.
What tract do the second-order neurons from Lissauer’s tract project their axons to?
The spinothalamic tract.
This tract is involved in transmitting pain and temperature sensations.
What information does the lateral spinothalamic tract carry?
Pain and temperature information.
It is a key pathway for nociceptive signals.
What is the role of the posterior funicular gray?
It contains second-order neurons that give axons across the midline.
This is part of the pathway that processes sensory information.
Where do the axons of the second-order neurons terminate?
In the thalamus, specifically the ventral posterolateral (VPL) nucleus.
This is the third-order neuron in the pain pathway.
True or False: The thalamus is unable to locate pain.
True.
The thalamus processes sensory information but does not localize pain.
What is the final destination of the third-order neurons in the pain pathway?
The primary somatosensory area or sensory cortex.
This area is responsible for interpreting sensory information.
Fill in the blank: The _______ tract is also known as the anterolateral pathway.
spinothalamic
This tract conveys pain and temperature sensations.
What types of receptors are involved in the pain pathway?
Receptors for pain, cold, warmth, tickle, and itch.
These receptors are critical for detecting various sensory stimuli.
What is the anatomical location of the first-order neurons in the pain pathway?
The posterior gray horn.
This is where sensory information enters the spinal cord.
What does the anterior spinothalamic tract primarily transmit?
Gross touch and pressure, crude touch, poorly localized touch (non-discriminative touch)
Involves non-discriminative sensory modalities.
Where do the axons of the anterior spinothalamic tract decussate?
Across the midline in the white commissure
This occurs at the level of the spinal cord.
What is the third-order neuron in the anterior spinothalamic tract?
Thalamus VPL
VPL stands for Ventral Posterolateral nucleus.
What is syringomyelia characterized by?
Development of a syrinx (fusiform cyst) in or beside the central canal, usually in the cervical region
Initial symptoms arise from obliteration of spinothalamic fibers.
What sensory modalities are affected by syringomyelia?
Sensitivity is bilaterally lost to painful and abnormal stimuli
This is due to the damage of spinothalamic fibers.
What does the posterior column - medial lemniscus pathway (PCML) transmit?
Proprioception, discriminative touch, pressure
Involves the fasciculus gracilis and fasciculus cuneatus.
Where do the fasciculus gracilis and cuneatus ascend?
To the medulla oblongata
These pathways carry fine touch and proprioceptive information.
What is the significance of the sensory decussation?
It is where the axons of the nucleus gracilis and cuneatus cross the midline
This transition into the medial lemniscus occurs.
What is the organization of the spinothalamic tract?
It includes anterior spinothalamic tract and lateral spinothalamic tract
Anterior transmits gross touch; lateral transmits pain and temperature.
What type of neurons are involved in the spinothalamic tract?
1st-order neuron (DRG), 2nd-order neuron (dorsal horn of spinal cord), 3rd-order neuron (thalamus VPL, VPM)
DRG stands for Dorsal Root Ganglion.
What does the term ‘somatotopic pattern’ refer to in the context of PCML?
The organized arrangement of fiber pathways representing different body parts
This organization is maintained throughout the pathway.
Fill in the blank: The anterior spinothalamic tract is associated with _______.
Gross touch
This tract is responsible for transmitting non-discriminative touch sensations.
