Exam #2: Lab Flashcards
What sensations are conveyed by the DC/ML pathway?
Proprioception
Discriminative touch
Vibratory sense
What sensations are conveyed by the Spinothalamic Tract?
Pain
Temperature
Crude Touch
What is Lissaruer’s Tract?
White matter tract just above the dorsal horn of the grey matter—these are myelianted axons from cell bodies in the first order neurons of the ascending Spinothalamic/ Anterolateral tract that carry:
- pain
- temp
- crude touch
What is the substantia gelatinosa?
2nd order neurons of the Spinothalamic Tract (from Lissauer’s Tract—ascend or descend 1st) that carry:
- pain
- temp
- crude touch
Where does the spinothalamic tract cross over?
Anterior white commissure
What is the fasiculus gracilis?
This is part of the DC/ML pathway thats transmits:
- Proprioception
- Fine discriminating touch
*****From T6 down
What is the intermediolateral cell column in the sacral spinal cord?
- Lateral column of the spinal cord
- PNS cell bodies located at S2, 3, & 4 that are PRE-GANGLIONIC cell bodies
What happens above T6 in the dorsal faniculi?
The fasiculus cuneatus emerges lateral to the fasiculus gracilis
At T4, what cell bodies are present in the interolateral cell column?
SNS—pre-ganglionic
Which is medial, Fasiculus Gracilis or Cuneatus?
Fasiculus Gracilis—always next to the dorsal median sulcus
What separates the Fasiculus Cuneatus & Gracilis?
Dorsal/ posterior intermediate sulcus
What is the Dorsal Nucleus of Clarke or Clarke’s Nucleus?
Nucleus in the thoracic cord that transmits proprioceptive fibers from the spinal cord to the cerebellum
In reference to the spinothalamic tract, what happens in the upper cervical spinal cord i.e. C1-C5?
This is the location of the junction between Lissauer’s Tract & CN V
- pain
- temp
- crude touch
*****All still being carried by these fibers; however, now they’re being carried by the cranial nerve.
What happens to the substania gelatinosa in the upper cervical region?
This is now the “Spinal Nucleus of CN V” or the “Gelatinosa” portion of CN V
What is the Gracile Tubercle?
Posterior swelling in the medulla that is the anatomic landmark for nucleus gracilis
What is the Cuneate Tubercle? Where is it relative to the Gracile Tubercle?
This is the anatomic landmark for the cuneate nucleus in the medulla
*****It is superior & lateral to the Gracile Tubercle
In the caudal medulla cross-section, what is the clearer staining region in the Fasciculus Gracilis?
Gracile Nucleus
In the caudal medulla cross-section, what is the clearer staining region inferior to the Fasiculus Cuneatus?
Cuneate Nucleus
What order neurons are in the Gracile Nucleus & Cuneate Nucleus?
These are the 2nd order neurons of the DC/ML pathway (proprioception & discriminative touch)
**Has NOT crossed over yet
What are the fibers that cross-over in the DC/ML pathway?
Internal arcuate fibers
Where are the internal arcuate fibers synapsing?
Gracile Nucleus & Cuneate Nucleus to the Medial Lemniscus
How is the ML organized?
Somatotopically
Outline the somatotopic organization of the ML in the medulla at the level of the sensory decussation.
“Drunken sailor that is still standing upright”
Neck Hand Chest Arm Leg Foot
What is the landmark for the rostral medualla?
Open 4th ventricle
What does the inferior cerebellar peduncle connect?
Cerebellum to the medulla & spinal cord
What is the landmark for the caudal pons?
Closed 4th ventricle Basilar pons (transverse fibers)
In the caudal pons, what region are the spinothalamic & DC/ML pathways in?
Tegmentum
How does somatotopic arrangement of the ML change in the caudal pons?
“Drunken sailor” gets a bit drunker & slouches i.e. becomes more horizontal
What is the landmark for the rostral pons?
Cerebellar hemispheres come into view
What happens to the ML & spinothalamic pathways in the rostral pons?
These previously distinct pathways merge in the tegmentum