CNS Focused Study (Exam II) Flashcards
What are two portions of the Dorsal Column Medial Lemniscus Pathway? What information do the two portions transmit?
Fasciculus Cuneatus - Upper Body Sensation
Fasciculus Grascilis - Lower Body Sensation
What sensory information does the DCML pathway transmit? How fast is the signal propogation?
- High Fidelity Sensory
(pinpoint touch, pressure, vibration, think hands)
- Very Fast
Where does crossover of the DCML pathway occur?
Crossover occurs at the Lemniscal Decussation of the Medulla Oblongata
Do any of the signals from the DCML interact with the gray matter of the spinal cord?
No
need to verify
What structure organizes sensory information from the DCML and directs it to the appropriate processing region of the cerebrum?
Ventrobasal Complex of the Thalamus
Where does sensory pain information crossover in the CNS?
How does this compare to regular sensory information?
Pain crosses over at spinal cord.
Sensory information crosses over at Medulla/Pons.
Describe the path of a general motor signal through the corticalspinal tracts starting with the cortex.
- Cortex
- Internal Capsule
- Medulla Pyramids
- Medulla Decussation
- Antero-Lateral Corticospinal Pathway
How much information is transmitted through the Lateral Corticospinal Pathway?
How does this compare to the Anterior Corticospinal Pathway?
- Lateral Corticospinal = 90% of motor output
- Anterior Corticospinal = 8-9% of motor output
What portion of motor information never crosses over at the pyramidal decussation or further down in the spinal cord?
1-2%
Where does motor output crossover for the lateral corticospinal tract occur?
Medulla Pyramidal Decussation
What are the two main paths of the Pyramidal Tracts? Which is the primary?
- Lateral Corticospinal Tract (Primary)
- Anterior Corticospinal Tract
Where does crossover occur for the Anterior Corticospinal Tract?
The level of activity initiation
(Ex. Signal going to calf muscle, crossover occurs at spinal nerve controlling calf)
What are the two Spinocerebellar Tracts?
Anterior Spinocerebellar Tract
Posterior Spinocerebellar Tract
What information is carried by the spinocerebellar tracts?
Feedback on the Coordination of movement.
What structure senses information for the Posterior SpinoCerebellar Tract?
Spindle Fibers in the Skeletal Muscle
What is the structure of spindle fibers and how does this relate to the information they transmit?
Where is this information sent primarily?
- Spring-like structure that “senses” contraction/stretch of muscle.
- Information is sent primarily to the Posterior Spinocerebellar tract.
Are muscle spindle fibers myelinated or unmyelinated? What does this mean in terms of pathophysiology?
- Spindle fibers are myelinated.
- Spindle fibers can be affected by demyelinating pathologies such as MS or Guillan Barre.
What sensors located in tendons send information to the spinocerebellar tract on muscle contraction?
Which spinocerebellar tract is this information primarily sent to?
- Golgi Tendon Stretch Sensors
- Anterior spinocerebellar tract.
Where do the Anterior (Ventral) spinocerebellar tracts end?
Superior Cerebellar Peduncle
Where do the Posterior (Dorsal) spinocerebellar tracts end?
Inferior Cerebellar Peduncle
What are the two divisions of the Spinothalamic (Anterolateral) Tracts?
Lateral Spinothalamic - Fast pain - A-δ
Anterior Spinothalamic - Slow pain - C
Where are A-δ fibers found in the spinothalamic tract?
What neurotransmitter(s) is used by this pathway?
How precise is the information delivered by this pathway?
- Lateral Pathway
- Glutamate
- Very precise (detailed pinpoint info)
Where are C-fibers found in the spinothalamic tract?
What neurotransmitter(s) is used by this pathway?
How precise is the information delivered by this pathway?
- Anterior Pathway
- Glutamate, Substance P, CGRP
- Imprecise (think stomach pain)
What two sensory receptor types run alongside C-fibers?
What is the consequence of this?
Thermoreceptors and Vibration receptors
*When slow pain is “activated” you can feeling heat, cold, tickles, and itching* (needs verification)