Lecture 13; 9/25 Flashcards
Test 3
The cord transmit _____ information from the peripheries to the brain/brainstem
sensory
Motor pathways are
Descending
Efferent
What are the majority of efferent pathways called?
Pyramidal
What are the 2 Pyramidal pathways called?
Lateral Corticospinal tract
Anterior Corticospinal tract
What are the Pyramidal pathways responsible for?
Majority of movement
What are the the 2 motor efferent pathways called?
Pyramidal tracts
Extrapyramidal tracts
What are the 4 extrapyramidal tracts called?
Rubrospinal tract
Reticulospinal tract
Olivospinal tract
Vestibulospinal tract
What are the extrapyramidal tracts responsible for?
Accessory motor pathways for complex tasks
we dont even know that it is happening
What is a tract?
Bundle of axons within the CNS
What is a nerve?
Bunle of axons outside of the CNS
Senory is _____ and Motor is ______
Up
Down
Sensory pathways are_______
Ascending
Afferent
Do we have more motor or sensory pathways? Why?
Sensory
We have much more sensory information being transmitted through the body than motor. Ex) Pressure, temp, pain, etc
Ascending and Descending columns are ______ bundled together
axons
Where does our touch/pressure sensory gets fed up from?
The Dorsal Column pathways
If our hands are up in the air, what pathway does this get fed up from?
The Dorsal Column pathways
Where are pain signals relayed from?
Anterolateral system
What does the anterolateral system consist of?
Anterior spinothalamic tract
Lateral spinothalamic tract
Through the spine into the thalamus =
Spinothalamic
How does pain signal travels?
Pain signals -> spine -> thalamus -> parietal cortex
What happens in the parietal cortex regarding pain?
Pain is sorted
Ex) how bad is the pain, where is it coming from, how severe is it?
Anterolateral =
Spinothalamic
What is Rexed’s Laminae?
Ways to divid grey matter in the cord
How is Rexed Laminae numbered?
Back to front
Dorsal to ventral
What is Lamina I responsible for?
Fast/Sharp pain
What is the alt name for Lamina I?
Lamina Marginalis
How does the signal travel on Lamina I
Alpha-Delta Fibers
Heavy Myelinated nociceptors
What is Laminae II and III responsible for?
Slow pain
What are Laminae II and III collectedly called?
Substantia Gelatinosa
What alt Laminae is responsible for slow pain?
V
How does the signal travel on Laminae II and III?
Non-myelinated C-fibers
Where are Mechanoreceptors located?
Laminae I - VI
What do Mechanoreceptors do?
Relay pressure sensory info to the areas where Laminae I-VI
Where is Laminae I-VI?
Dorsal horn
What does Lamina Marginalis mean?
Tip of Dorsal Horn
How many Laminae are there in total?
10
Where does crosstalk happen in the grey matter?
Laminae X
Where does crosstalk happen in the white matter?
Anterior white commisure
Where are the majority of large motor neurons?
Laminae VIII
Why is the ventral horn bigger than the dorsal?
Cell bodies from multipolar motor neurons
Where is Laminae X located?
In the center of the grey matter. Surrounds the central canal
What does the Spinocerebellar tract do?
Bring sensory info from the spine to the cerebellum
What is the nickname for the Dorsal-Column Medial Lemniscal System?
DCML
Describe the Dorsal-Column Medial Lemniscal System
Major pressure sensory and touching sensitive pathway
Passes through the Medial Lemniscal of the brainstem
In the Dorsal part of the cord
Spinothalamic tract =
Pain
Corticospinal tracts alt names
Descending motor pathways
Pyramidal tracts
Where does the Corticospinal tracts originate?
Cerebral cortex / motor cortex
Where is our motor cortex?
Pre central sulcus
Frontal lobe
Where is our cerebral cortex?
Most superior part of brain: Telencephalon
Where does the Extrapyramidal tracts originate?
Brainstem
The higher in the cord we go the _____ the dorsal column is
Bigger
Which part of the dorsal column changes?
The Fasciculus Cuneatus
What is the lateral part of the dorsal column?
Fasciculus Cuneatus
Describe the Fasciculus Gracilis vs Fasciculus Cuneatus
Fasciculus Gracilis: Sensory pathway for muscles in lower extremities
Fasciculus Cuneatus: Sensory pathway for muscles in upper extremities
What type of fibers are used in the DCML?
Heavily myelinated A-fibers
Alpha
Beta
Delta
Gamma
(Fine vibrations and Fine pressure)
The Gracilis muscle is located where?
Leg
Describe A-fibers
Very fast signaling
Where does crossover happen in the DCML?
Lower part of the Medulla which is at the bottom of the brainstem
What is the Ventrobasal Complex?
Part of the thalamus that runs info to the parietal lobe in the DCML pathway
Describe the internal Capsule
Sits outside of the thalamus
The DCML pathway passes through here AFTER going through the thalamus on the way to the cerebral cortex / parietal lobe
Describe the pathway for DCML for a foot tickle
Dorsal root/spinal ganglion -> dorsal rootlets -> ascending Fasciculus gracilis -> Lower medulla oblongata -> Medulla oblongata -> Medial Lemniscus -> Ventrobasal complex of the thalamus -> Internal Capsule -> Cerebral cortex/parietal lobe
What are the body parts affected from the postcentral gyrus by DCML pathways from anterior to posterior
Lower extremities
Trunk
Upper extremities
Face
Where are the majority of our pressure sensors?
Hands and Face
Why are corticospinal tracts called Pyramidal tracts?
Because they pass through the pyraminds in the brain stem
Where does the Lateral corticospinal (primary) pathway originate?
Cerebral corbex (frontal lobe/precentral sulcus/primary motor cortex)
What is the pathway of the Lateral corticospinal pathway?
Cortex -> Internal Capsule -> Pyraminds of Medulla -> Crossover at the Pyramidal Decussation on the Medulla -> Lateral Corticospinal tract
Where does crossover happen in the Lateral Corticospinal (Primary) pathway?
Pyramidal Decussaton on the Pyramids of the Medulla
Where are the pyramids of the medulla located?
Ridges on the anterior brainstem
____% of Motor signals come from the anterior corticospinal tract
17%
Where does crossover happen in the anterior corticospinal tract?
In the spinal cord at the level where message needs to be communicated at
What % of info doesnt get crossed over at all?
2-3%
