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161 Cards in this Set

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Imagine what fibers are contained in the spinal roots vs trunks vs rami?
What structures do the dorsal vs ventral rami serve?
they each serve all the sensory receptors and motor muscles of their respective side of the body.
Why are they called anterior and posterior roots and trunks?
Because they litterally look like a set of roots coming from the anterior and posterior side to make a common trunk.
What is a spinal column of white matter also called?
Funiculus
What is the root of funiculus?
something embeded in a CT fascicle
Imagine what each of our funiculuses look, how many we have, and the direction of their neuronal fibers. (up/down)
Which columns are most modern?
dorsal
Which column are more primitive (earlier in evolution)?
anterior and lateral
What does this mean for modern beings?
we have a whole two extra columns of sensory old fibers that help us experience more in life.
What analogy can you use to compare dorsal and anterolateral columns? Why is this sppropriate?
Dorsal is an expressway because it is heavily myelinated. Anterolateral is not as myelinated and is a dirt road.
Where can you fine crude touch sensory fibers vs fine touch?
crude- anterolateral
fine- dorsal
Which columns have more variety in the types of sensations they hold? Mnemonic?
the primitive system because on a dirt road you will see every type of vehicle including bikes and horses, but there will only be cars in the expressway.
What are some examples of primitive sensations?
think very essential sensations like pain, tickling, temperature, itching, sexual pleasure, and crude touch
What are the qualities of the types of sensations that go through the dorsal column?
They are modern, need to be fast, and need to be super analyzed.
What are some examples of modern sensations?
fine touch (vibration, two point discrimination), proprioception
Why does proprioception need to be fast?
we can't **** up all these movements or else we'll fall
Where does the proprioception senses go to?
the cerebellum
When can proprioception go to the cerebral cortex?
when we pay attention to it and unlock the gates
How are the primitive and modern tracts different in ability for localization and gradation?
The modern tracts are better at both localization and gradation
What implications does this have for our ability to say where pain is?
Since it is primitive, we are very bad at saying exactly where the pain we feel is.
What implications does this have for our ability to dance?
We are able to dance because our sense of proprioception is so good!
Imagine the path of a sensory fiber from the body to the fasiculus
Draw the medial to lateral organization of the dorsal tract as well as the two fasiculi in the column using the graceful ballerina mnemonic. Which portions of the body does each fasicle serve?
What happens if you have a tumor squishing the dorsal lateral part of the spinal cord?
the upper part of the body will lose fine/proprioceptive sensation.
Do the fasiculi contain all types of modern sensory fibers?
Yes, both fine touch and proprioception! They only discriminate between anything above or below T6.
If you take a coronal section of the spinal cord at T7, how many fasiculi would you expect to find in a dorsal column? What are they called?
One. Fasciculus gracilis.
How well arranged are the fibers within the fasiculi?
very precisely arranged from lower body to upper body.
Do the sensory tracts cross sides in the spinal column?
No, they ascend ipsilaterally
Imagine the body parts represented in the dorsal columns.
Imagine how you would lose sensation if there was a growing tumor in the medial posterior spinal cord.
Imagine how you would lose sensation if there was a growing tumor in the right lateral posterior spinal cord growing to the left.
describe the previous scenario in words.
you would lose sensation starting on the RIGHT side of whatever level you are on (info will go to left brain though), which will move down and then back up the other side.
What is a 1st order sensory fiber?
The one that starts at the dorsal root ganglion
Imagine what the medulla looks like and what it is connected to the cerebellum with.
Where will the first order dorsal sensory fibers terminate?
in their respective nucleus in the medulla. (nucleus gracilis or cuneate)
Imagine what the nuclei look like in the medulla.
Imagine what the crossing of the dorsal columns looks like?
What are the crossing fibers called? Why? What part of the medulla do they exist in?
internal arcuate fibers because they arc accross at the lower end of the medulla.
Where do the arcuate fibers go?
to the medial laminicus, which travels up
What is this whole dorsal sensory system called then?
Dorsal column-medial laminiscal system
What does a fascicle vs laminiscus fibers look like? (imagine)
What is the derivative meaning of laminiscus?
laminar = a flat plane
Imagine the path of the medial laminisci and where they terminate.
Essentially what are the thalami?
Two eggs full of nuclei
Imagine the 3/4 groups of nuclei of the thalami. What are they called?
What are the front and back nuclei of the lateral part of the thalamus called?
ventral and dorsal thalamic nuclei
When referring to these lateral thalamic nuclei, do you have to put lateral in front of them? Why?
No because you use anterior to refer to the front portion of the anterior thalami so dorsal and ventral are words unique to the lateral thalamus.
Imagine the nuclei in the lateral ventral nuclei group and label them. (3)
Which nuclei do the secondary dorsal fibers terminate on?
The ventral posterolateral
The first scientists cut a cross section of the brain at the thalami, what did they see lateral to them? (where the fibers head next) IMAGINE
In the last picture, what is grey matter and what is white?
What is that cheese looking thing called?? Why?
Lenticulate nucleus because it looked like a telescope lens to those scientists.
What are the two pieces of white matter called and why?
Internal and external capsule (of the lenticulate nucleus) because they look like they are enclosing it and were white.
Do the internal and external capsules actually wholly encapsulate the lenticulate nucleus?
No
What is in between the capsules?
The caudate nucleus.
Can you draw the rat, egg, and cheese mnemonic for the caudate nucleus?
What does the caudate nucleus look like in relation to the thalamus in 3D space?
like a bluetooth device in someone's ear with the bottom part wider.
What is the part that goes into the ear called?
the lenticular nucleus, which the caudate nucleus rat is "tasting"
Which portion is the caudate nucleus rat "tasting"? What do I mean by "tasting"?
Tasting means this is where they are connected and it is at the anterior side of the lateral section called the putamen.
Real 3D image of caudate nucleus.
Imagine how the internal capsule passes through the caudate nucleus.
Imagine the two parts of the internal capsule.
Imagine which part of the internal capsule the tertiary dorsal fibers travel through the internal capsule.
Imagine what do the tertiary sensory fibers do after passing through the internal capsule. What do they become?
Where do the fibers of the corona radiata end?
In the cerebral cortex in the post central gyrus aka the sensory cortex.
What is a gyrus?
One of the lumps on the brain. (not a valley like a sulcus)
Show the lateral view of the post central gyrus on the brain.
Break down the meaning of POST CENTRAL GYRUS.
That lump that is POSTerior to the CENTRAL GYRUS
What are the receptors for pain vs temperature made from?
Essentially what are the pain fibers sensing?
Any kind of tissue damage.
Show some substances that stimulate pain. (4)
What three related prcesses are these substances indicative of? Which ones?
1. tissue damage - H+, K+
2. inflammation - histamine, bradykinin
3. platelet aggregation - 5-HT
Show some substances that lower the pain threshold.
Show how the pain and temperature fibers travel through the spinal cord
Where does this tract terminate?
in the thalamus
So what would this whole system be called?
The lateral spinothalamis tract.
Where is the tract of lissauer located? How do fibers travel through it?
dorsolateral to the dorsal horn. Fibers from the primary sensory neuron enters here from the dorsal root and either travels up or down a few levels and then exits to the substantia gelatinosa.
What is the pattern of fibers in the spinal cord from feet to head? How is this similar to the dorsal-thalamic tract?
the lower neurons add more laterally on the contralateral side. They both go to the furthest spot over on the side that they are on.
To the picture before, add in the crude touch pathway.
In what ways is the crude touch pathway similar to the pain and temperature pathway?
They both enter through the dorsal route and travel the same way throught the tract of Lissauer to the substantia gelatinosa.
In what ways are they different?
Crude touch crosses contralaterally to the anterior fasculis whereas the others go to the lateral fasiculus.
How do the fibers line up in the anterior spinothalamic tract?
The same as the lateral spinothalamic. The lower levels go to the farthest contralateral side.
What are the primitive sensory spinal pathways called collectively? (2 names)
The anterolateral system
The spinal-thalamic pathway
Draw out the categories of sensory pathways so far and include the type of sensation they serve.
What is the spino-tectal pathway (new) functional for?
for the reflex of turning your head and eyes at some sensory information.
Why is it called tectal?
Because that's where it terminates.
Draw a lateral view of where the spino-tectal path travels in the spinal cord and where it goes in the brain.
What are the superior and inferior colliculus called collectively?
tecta
Draw how the spinalthalamic and spinotectal pathways travel through the hindbrain together and where they end up generally.
There is actually white matter in the thalamus. Draw it out and name it and the nuclei within it.
What are slow vs fast pain fibers also called?
slow- C fibers
fast- A d fibers
The slow pain fibers go to unique places from the fast pain/modern fibers. Show where that is.
What is the main function of the reticular formation?
to bring things to consciousness
When you are sleeping, do sensory signals reach the sensory cortex? Why?
NO! Because the reticular formation is a main switch of the cortex and it is down during sleep.
Draw the lateral view of the reticular formation and the thalami.
Draw the pathway by which the reticular formation activates the cerebrum
Do any other sensory fibers go to the reticular formation? How?
Yes, they all do by making collaterals with it on their way to other places.
Which tract makes the most impact on activating the cerebral cortex? Why?
The slow/visceral pain C-fibers because they have the most connections with the reticular formation and also go directly to the intra laminar nuclei which will also activate the cortex.
Why is the reticular formation's function so important?
Because we NEED our cortex to be active when there is a strong sensory stimulus (especially pain) so that we can fix it.
How does this explain why throwing a bucket of water on someone wakes them up?
It's a strong sensory stimulus which activates the reticular formation.
How does this explain why I felt so alive after jumping off that ramp in the theater parking lot?
Same thing, now you know!
What kind of pathological behavior does this explain?
One of the reasons for self harm.
What does the post central gyrus do with the sensory information that it gets?
It processes it by comparing it with the past and also helps to localize the pain exactly.
Which type of pain fiber goes most to the postcentral gyrus?
The fast pain fibers
What implication does this have for us to point out different types of pain?
Sharp pain can be pinpointed exactly, but visceral and chemical pain we feel as a more general area.
What general pathway do the spinothalamic fibers take after they reach the thalamus?
Pretty much the same as the dorsal-medial lamiscus pathway. (Posterior limb of internal capsule to the postcentral gyrus)
Besides just being brought to consciousness for analysis and evaluation, what other responses does pain elicit in the brain?
An emotional response and an autonomic response
Draw the part of the brain responsible for emotional and autonomic responses to pain. Include the pain pathways there and what lobe they are on.
So which ones are for emotion and which ones are for autonomic response?
Emotional- cingulate cortex on Parietal lobe
Autonomic- Insular cortex on temporal lobe

Pain fibers all head there after hitting the posterior limb
What is the cingulate cortex a part of?
the limbic system.
A picture of the how the cingulate cortex sits laterally.
Right above the
Right above the corpus collasum
What is the difference between a gyrus and a cortex?
A cortex is a region of gyri and sulci
How can I remember the extra functions of pain on the cortex?
If you get punched in the gut, you will get very alert (reticular formation and sympathetic stim) and very upset (cingulate cortex)
What is a transection?
A section taken out of something in the transverse plane.
If you take a trans hemisection, out of the spinal cord, what sensations will you lose?
Ipsilateral fine touch/proprioception below that level
Contralateral pain, temperature, and crude touch below and some above
Ipsilateral pain, temp, crude several levels above and below
What syndrome does this hemisection cause?
Brown Sequard Syndrome
Show a picture of this syndrome.
Imagine the connections of the fast vs slow pain fibers within the ipsilateral spinal cord before crossing. Which one is more direct?
Imagine the road mnemonic for the slow vs fast pain connections. Implications?
What have we found to replace the gate control theory of why producing other sensations dulls pain?
What kinds of phenomenon use this mechanism of pain control to their advantage?
massage, acupuncture, caressing
What is the emotional component of pain? Does it hurt more if we fall down the stairs or someone slaps us?
Emotions from the brain have tracts that descend to regulate pain sensation. So it hurts more if someone slaps us.
where does the descending analgesic system comes from and what they release and where.
Peiventicular, periductal (cerebral aquaduct), and other central nuclei that descend down to the dorsal horns to release endorphins and enkephalins
What type of tissue were the organge circles by the ventricles and midline?
grey matter
What substance are enkephalins and endorphins similar to?
morphine
DO they have a mild or strong effect?
strong
WHat does that mean for being able to regulate your own pain?
If you are running or feeling good, you may not feel the pain anymore.
What are the 3 levels of pain that have to be examined to determine the end effect?
1. Pain transmission
2. Pain perception
3. Painmodulation
What is pain transmission?
Pretty much what we have been learning so far with the ascending tracts
NOW WE TALK ABOUT THE CEREBELLUM!
YAY!
What are the pathways that take sensory info from the spine to the cerebellum?
spinocerebellar pathway.
In what orientation are these fibers taking this info? Is this direct or indirect?
They connect ipsilaterally and it can be either direct or indirect
What are the different types of sensory cerebellar pathways and why are they named this way?
1. Dorsal/posterior spinocerebellar tract
2. Anterior spinocerebellar tract
They are named for how they travel in the lateral column
What kind of receptors use the dorsal cerebellar pathway to travel to the cerebellum? (3)
Golgi tendon
Muscle spindle
Pressure receptor
Draw the beginning of the dorsal cerebellar pathway in the spinal cord.
STate the path.
They start 1st order neuron in the dorsal root, synapse again in the dorsal root, move to the ipsilateral posteriior lateral column and go up.
How are the dorsal horn nuclei arranged for this system?
linearly in a column called Clarke's column or dorsal nucleus
What are the midbrain, pons, and medulla connected to the cerebellum with?
The superior, middle, and inferior cerebellar peduncles
Where does the dorsal/posterior cerebellar tract go to get to the cerebellum?
Through the inferior cerebellar peduncle in the medulla
Imagine which levels are dorsal root ganglion present in Clarkes's nucleus? What implication doe this have for connections at the bottom?
So how do we take golgi, spindle, and pressure info from above C8 to the cerebellum.
In the same way except we use another column of nuclei.
Imagine what these upper dorsal horn nuclei look like. What are they called? Which parts of the body does it serve compared to Clarke's?
What is this pathway for the golgi, spindle, and pressure sensation from the arms and neck to the cerebellum called?
The cuneatocerebellar pathway.
Why is this superior column of nuclei called the accessory cuneatus nuclei?
Because scientists first thought it was related to the cuneatus nuclei of the dorsal column- medial lemiscus pathway because it goes to the same level, but it isn't.
Show the two cuneatuses together.
Show the pathway of the anterior spinocerebellar pathway in one level of the spinal cord.
Describe the pathway.
Info is taken in from the dorsal root, synapses in the ipsilateral dorsal horn and then crosses to the contralateral anterior side of the lateral column.
Show the final journey of where the anterior spinocerebellar pathway goes after that.
Describe this journey.
They pass up contralaterally from the anterior lateral column to the superior cerebellar peduncle and then cross to the ipsilateral side in the cerebellum.
What are the 3 extra minor sensory pathways?
1. Spinotectal pathway
2. Spino-olivary pathway
3. Spino-reticular pathway.
What function does the spinotectal pathway have?
Visual reflex
What function does the spino-olivary pathway have?
Same as the spino-cerebellar except through an alernate path
What function does the spino-reticular pathway have?
Stimulates the reticular formation to activate the whole cortex
Draw out these 3 minor pathways and remember that some are ipsilateral and some are contralateral.
Make a flow chart of the major and minor ascending tracts
Make a flow chart of the pathways of the major ascending tracts.
What pathway takes pain and temperature up to the cortex?
Lateral spinothalamic.
What pathway takes crude touch up to the cortex?
Anterior spinothalamic
What pathway takes propioception up?
Need more info about whether this is reaching consciousness
WHich one is conscious and which is non conscious?
conscious- dorsal- medial leminiscal
non conscious- spinocerebellar