Lecture 11: Ascending Pathway II (ALS) Flashcards
True or False: There is a fair amount of redundancy in the spinothalamic tract, spinoreticulothalamic tract, and spinotectal tract
True
True or False: The spinothalamic tract, the spinoreticulotract, and the spinotectal tract all contains a three neuron chain, similar to the DC-ML
True
Where is the primary and secondary neuron located in the ALS System?
Primary = cell body (DRG)
Secondary = substantia gelatinosa (lamina II) or lamina V of the dorsal horn of the spinal cord
Which three peripheral receptors are associated with the ALS?
Nociceptors
Thermoreceptors
Thermal Nociceptors
True or False: The peripheral axonal processes of the ALS start at the peripheral receptor and end in cell body of the DRG
True
In the ALS, nociceptors are associated with type 3 fibers (Agamma) and type IV (C) fibers. The prior are ____ axons for transmission of fast, sharp pain (first pain) whereas C are small ____ for transmission of slow, burning pain (second pain)
A. highly myelinated; unmyelinated
B. lightly myelinated; unmyelinated
C. non-myelinated; unmyelinated
B. lightly myelinated; unmyelinated
True or False: In the ALS, thermal receptors and thermal nociceptors are associated with Agamma and C fibers
True
In the ALS, the central axonal process starts at the cell body in the DRG and ends in the ___ of the spinal cord
A. Ventral Horn
B. Dorsal Horn
B. Dorsal Horn
The ALS central axonal processes enter the spinal cord through the _____ entry zone to enter ____ tract
A. medial dorsal entry zone; Lissauer’s tract
B. lateral dorsal entry zone; Lissauer’s tract
B. lateral dorsal entry zone; Lissauer’s tract
In the ALS system, there are collateral branches of the central processes that may ascend or descend in Lissauer’s tract and will terminal in the _____ to facilitate spinal reflexes
spinal gray matter
True or False: In the ALS, the main axon will enter the gray matter of the dorsal horn and synapse onto the third order neuron in the pathway
False - second order neuron
Which axons of the ALS will decussate in the anterior white commisure of the spinal cord and coalesce in the ____ as part of the ALS
A. spinal gray matter
B. spinal white matter
B. spinal white matter
True or False: The decussation of the second order neurons in the ALS does NOT take place at the level at which the information enters the spinal cord on the primary afferent, but it occurs over 1-2 spinal segments rostral to entry level
True
Which tract of the ALS is concerned with sharp, fast pain sensations?
A. STT
B. SRTT
C. SpTT
A. STT (spinothalamic tract)
True or False: The spinothalamic tract is somatotopically organized
True
In the STT, axons from the sacral cord are located ___ while those from the cervical cord are located ____
A. medially; laterally
B. laterally; medially
B. laterally; medially
The STT ascends in the ventrolateral aspect of the spinal ____ ____ over length of spinal cord
A. gray matter
B. white matter
B. white matter
In the medulla, the STT is located dorsolateral to the ____
In the pons, the STT is located lateral to the ___ ___
In the midbrain, the STT is located dorsolateral to the ___ ____
A. ML; ML; Superior Olivary Complex
B. Inferior Olivary Complex; ML; ML
C. ML; ML; Inferior Olivary Complex
B. Inferior Olivary Complex; ML; ML
The STT enters and terminates on neurons in the _______ - the third order neurons of this pathway
A. Medial Lemniscus
B. DRG
C. Spinal Gray Matter
D. Ventral Posterolateral Nucleus (VPL) of the Thalamus
D. Ventral Posterolateral Nucleus (VPL) of the Thalamus
True or False: The third order neuron of STT is located in the VPL nucleus of the thalamus
True
True or False: Fibers of the STT will synapse on neurons in the VPL
True
In the STT, axons of the VPL neurons project laterally out of the thalamus and course though the posterior limb of the ___ ___ to terminate in the _____ of the post central gyrus
A. ML; 1 Somatosensory Cortex
B. Internal capsule; Primary Somatosensory Cortex of the Post Central Gyrus
B. Internal capsule;
Primary Somatosensory Cortex of the Post Central Gyrus (Area 3, 1, and 2 Brodmann)
True or False: In the STT, the primary somatosensory cortex is located in the post-central gyrus of the parietal lobe; somatotopy is not preserved here and various body parts are equally represented in sensory homonculus
False - while in the STT, the primary somatosensory cortex is located in the post-central gyrus of the parietal lobe; somatotopy IS preserved here and various body parts are NOT equally represented in sensory homonculus
The second order fibers of the ALS course through the _____ to gain the contralateral side of the spinal cord.
Decussation occurs over distance of ___ spinal cord segments
anterior white commissure; 1-2
Which of the following tract of the ALS is concerned with slow, dull, aching pain and crude touch?
A. STT
B. SpTT
C. SRTT
C. SRTT
True or False: The spinothalamic tract is a indirect tract while the spinoreticulthalamic tract is considered to be a direct tract
False - STT = direct; SRT = indirect
Why do axons of the SRTT not end in the thalamus directly?
Leave tract as it courses through brain stem to synapse on neurons in the reticular formation
Where are the third order neurons of the SRTT located?
A. DRG
B. Thalamus
C. VPL of the Thalamus
D. Reticular formation of brainstem
D. Reticular formation (network of neurons in core of brainstem)
Where do third order neurons of the SRTT project their axons to?
A. Reticular Formation
B. VPN of the thalamus
C. Thalamus (intralaminar nuclei)
C. The thalamus (intralaminar nuclei of the thalamus)