Lecture 1 Test 3 Flashcards
What part of the spinal cord transmits sensory pathway in ascending (afferent)?
(Blue part) mostly dorsal and some lateral
What part of the brain does the information being sent through the spinal cord go to?
Brain stem, cerebellum and brain
What part of the spinal cord transmit in descending (efferent) motor pathways?
lateral corticospinal
What has a larger area in the spinal cord between sensory and motor pathways?
Sensory pathways
Name different types of sensors the body has?
Pressure sensors in the skin, temperature, vibration, and pain sensors
Which pathway takes up more real estate in the cord?
Ascending (sensory) pathway
What does the gray matter mainly do?
Decision making through synapses
What’s in the gray matter?
Cell bodies of motor neurons and parts for communication (synapses/decision making)
Bundle of axons outside of the CNS
Nerves
Bundle of axons within the CNS
Tract
What are the 2 main groups of descending pathways?
Pyramidal tract; extra pyramidal tract
Which descending tract does the primary (voluntary) motor function that we think about go through?
(Arm movement, leg movement)
Pyramidal tract
accessory motor pathways (complex tasks)
no realization of these things functioning but fine tune motor commands.
help control or give feedback on instructions
Extrapyramidal tract (outside of pyramidal tract)
If the pressure sensor needs to make it up (ascend) to the brain, which pathway does it go?
Dorsal column
The higher you go up in the cord, the ____ the dorsal columns are gonna be.
Larger
Where does the ascending crossover of the left side of the brain to the right side of the brain occur?
At the DCML lemniscus decussation located at the lower part of the medulla
What is the medial lemniscus?
This is a structure that the information travels through to get to the brain stem after the crossover process.
Where does the DCML information get routed through after the thalamus?
Ventrobasal Complex
What’s in charge of running the sensory information up towards the parietal lobe of the brain.
Ventrobasal Complex
Meaning of corticospinal
Signal originated from the motor cortex
Where does 80% of our motor function occur in the spinal cord?
Primary pyramidal tract
located in our skin
figure out if we’re holding on to something
we have our hands up in the air.
o pressure sensors (touch perception)
o Aka spinothalamic tracts, or spinothalamic pathways
o Anterolateral column pathway
Where are pain signals relayed?
spine and up the thalamus (spinothalamic tract) and then the parietal lobe
A system of 10 layers of gray matter within the spinal cord and their functions. Numbered from back to front
Rexed’s Laminae
Aka “Lamina marginalis”
First tip of dorsal horn
Lamina I
What type of pain fibers does Lamina I use?
Fast pain myelinated nociceptors (A(d) -Fibers)
Fast pain pathway
Neospinothalamic pathway
aka Substantia gelatinosa
Lamina II & III
What type of pain fibers does Lamina II & III use?
Slow pain; nociceptors that are non-myelinated C fibers
Sometimes Lamina II & III has a synaptic connection with
Lamina V
Activated by the descending motor pathways; motor neurons are located here
Anterior horn
anterior Horn can be elicited to send action potentials when stimulated by
Brain motor center or reflex ARCs
middle of the gray matter, allows for signals to get routed to the other side of the cord
Lamina X
o the portion of tissue that can relay information to the other side of the cord that’s made up of white matter.
Anterior White Commissure
Five different categories of spinal tracts
Spinocerebellar tract, Dorsal-column medial Lemniscal system (DCML), Spinothalamic/anterolateral tracts, Corticospinal tracts (pyramidal tracts), Extrapyramidal tract
o send information from the spinal cord up to the cerebellum.
Spinocerebellar tract
o major pressure sensory pathway (touch-sensitive) other than pain
Dorsal-column medial Lemniscal system (DCML)
structure that the motor information x-over through to the brain stem before the thalamus.
o Lemniscal decussation
What type of neurons does DMCL use?
fast signal propagation (A fibers)
variety of A (myelinated) fibers
o A alpha
o A beta
o A delta
o A gamma
What type of sensory fibers do pressure, vibration use?
all 4 (A alpha, A beta, A delta, A gamma)
Pain tracts
Spinothalamic (anterolateral) tracts
o signal originated in the cerebral motor cortex and now going down the cord through
Lateral Corticospinal tracts (pyramidal tracts)
Left side of the CNS takes care of the function on the ____ of the body
Right side; and vice versa.
Where does the signal crossover in the brain?
Medullary decussation
Which direction does touch information travel?
1) it goes into the gray matter of the cord and stays there (lateral inhibition, or modulation of some activity in the cord).
2) takes it up towards the brain through the dorsal columns.
the further up the cord you get, the ____ dorsal column structure is.
wider; larger
Lower extremity information is fed into (dorsal column). (inferior section of the cord)
Fasciculus Gracilis
Upper extremity information are fed into (dorsal lateral column)
Fasciculus Cuneatus
Grouping of larger dorsal column includes lower and upper extremity going up towards the brain.
Fasciculus Cuneatus
Relay center of the middle part of the brain
Thalamus
*part of the thalamus where this DCML information gets routed through.
*in charge of running this sensory information up towards the parietal lobe of the brain.
Ventrobasal complex
o information pass through this structure on the way to the parietal lobe.
o sits just outside of the thalamus
o right between the thalamus and parietal lobe
Internal Capsule
Pressure/vibration > dorsal root > dorsal rootlets > DCML > crossover at medial lemniscus decussation -> ventrobasal complex of thalamus -> internal capsule -> out to parietal lobe (post central gyrus)
takes care of information coming from the lower extremities.
top part of the parietal lobe
takes care of information from the trunk
Middle top of parietal lobe
takes care of information from the upper extremities
Bottom of the parietal lobe
in charge of the information from the face (parietal lobe)
bottom borders of parietal lobe
stroke effects are based on ___
placement in the parietal lobe
o Creepy drawing to illustrate the topography region
Homunculus
hands/face have tons of
pressure sensors (sensitive).
Detailed info needs lots of
Pressure sensors
Parts of the brain that process a lot of info are ___
Large in portion because of the amount of sensors it needs to process
We have more pressure sensitive sensors in our feet or hands?
Hands
Smaller portion of the brain, lower density sensory receptor that’s in charge of this body part?
Trunk/torso
Descending motor pathway (2 parts)
Pyramidal tract; Extrapyramidal tract
80% (4/5) lateral descending pathway (bigger)
(Primary) Pyramidal tract
Where signal crossovers occur at the last part of the medulla
pyramids of the medulla
To cross over to the other side of the brain stem
Pyramidal decussation
bridges the gap between the left and right pyramids (majority of motor signals)
Pyramidal deposition
Which tract does 17% of anterior descending pathway (smaller) occur. Crossover occurs at the level of the cord.
(Secondary) Pyramidal tract - Anterior corticospinal tract
About how many signals do not crossover at all?
3%
o targets, for your drugs (anesthesia)
Descending pain inhibitory complex
Are you born with NMDA-R?
No its a growth development from the CNS
T/F: AMPA-R increases due to chronic pain
True
What are the 3 ionotropic receptor
AMPA-R, NMDA-R, Kanate-R
What type of receptors are metabotropic?
GPCRs
How is iNOs related to pain?
Induced by pain and increases sensitivity of pain synapse
4 types of extrapyramidal tract sensors
Vestibulospinal - eye fixation, muscle orientation
Olivospinal - cerebellar output to coordinate movement
Rubrospinal - modulation voluntary movement
Reticulospinal - maintain muscle tone
