Neurology | Spinal Cord: White Matter Structure & Function

Summary

This educational video offers an in-depth exploration of the spinal cord's white matter, focusing on its structure and function. It explains the concept of white matter as myelinated axons and introduces the term 'tract' as bundles of axons in the central nervous system. The video outlines the anatomy of the white matter in the spinal cord, including dorsal, lateral, and ventral columns, and discusses the ascending and descending tracks that carry sensory and motor information. It provides a detailed overview of specific tracts like the tract of Lissauer, corticospinal, reticulospinal, and spinothalamic tracts, emphasizing their roles in pain, temperature, touch, and motor control. The script also highlights the somatotopic organization of these tracts, crucial for understanding the implications of spinal cord injuries.

Takeaways

• 🧠 The white matter of the spinal cord is primarily composed of myelinated axons, which give it a whitish appearance.
• 🌐 Myelin sheaths are lipid-protein layers that insulate axons and facilitate the rapid transmission of action potentials.
• 🔄 A tract, or fasciculus, is a bundle of axons in the central nervous system that transmits information either ascending (sensory) or descending (motor).
• 🌱 The white matter is anatomically divided into dorsal (posterior), lateral, and ventral (anterior) columns relative to the gray matter of the spinal cord.
• ➡️ Ascending tracts carry sensory information up the spinal cord, such as the spinothalamic tracts responsible for pain and temperature sensations.
• 🔽 Descending tracts, like the corticospinal tracts, carry motor information down the spinal cord to stimulate voluntary muscle control.
• 🔄 The tract of Lissauer is involved in the pain and temperature pathway, with fibers ascending or descending one or two segments before synapsing in the posterior gray horn.
• 🏃‍♂️ The lateral corticospinal tract is the most significant descending motor tract, responsible for voluntary control of skeletal muscles.
• 🦾 The somatotopic arrangement of the lateral corticospinal and spinothalamic tracts places the sacral region laterally, followed by lumbar, thoracic, and cervical.
• 👣 The dorsal column contains only ascending tracts, specifically the fasciculus gracilis and fasciculus cuneatus, which transmit fine touch, vibration, and proprioceptive sensations.
• 🧍 The anterior spinothalamic tract in the ventral column carries crude touch and pressure sensations.

Q & A

What is white matter in the context of the spinal cord?

White matter in the spinal cord refers to the myelinated axons, which give the tissue its whitish appearance due to the myelin sheaths that insulate the axons and facilitate quick transmission of action potentials.

What is the function of the myelin sheath in neurons?

The myelin sheath serves as an insulating layer around the axon of a neuron, allowing for faster transmission of action potentials along the axon.

What is a tract in the context of the central nervous system?

A tract is a bundle of axons within the central nervous system that facilitates the transmission of information either ascending (upwards) or descending (downwards).

What are the different columns of white matter in the spinal cord?

The different columns of white matter in the spinal cord are the dorsal white column (posterior to the gray matter), the lateral white column (on the sides), and the ventral white column (anterior to the gray matter).

What is the anterior white commissure and its significance?

The anterior white commissure is a structure in the spinal cord where crossing of fibers occurs, allowing for the transmission of information across different sides of the spinal cord.

What is the function of the tract of Lissauer and how does it relate to pain and temperature sensations?

The tract of Lissauer is involved in the pain and temperature pathway. It allows these sensory fibers to ascend or descend one or two spinal cord segments before synapsing on the cell bodies in the posterior gray horn, which is important for understanding the levels affected by a lesion in the spinal cord.

What is the primary descending motor tract in the lateral white column of the spinal cord?

The primary descending motor tract in the lateral white column is the lateral corticospinal tract, which is crucial for voluntary control of skeletal muscles.

What are the two main ascending tracts in the dorsal white column of the spinal cord?

The two main ascending tracts in the dorsal white column are the fasciculus gracilis and the fasciculus cuneatus, which are responsible for carrying fine touch, vibration, and proprioceptive sensations.

What is the somatotopic arrangement of the lateral corticospinal tract and its significance?

The somatotopic arrangement of the lateral corticospinal tract places the legs laterally, with sacral motor supply being the farthest lateral, followed by lumbar, thoracic, and cervical. This arrangement is significant for understanding the impact of lesions on specific body regions.

What types of sensations are carried by the dorsal spinocerebellar and ventral spinocerebellar tracts?

The dorsal and ventral spinocerebellar tracts primarily carry proprioceptive sensations, which provide information about the position and movement of the body in space.

Outlines

00:00

🧠 Introduction to White Matter of the Spinal Cord

The video script begins with an introduction to the white matter of the spinal cord, explaining its basic structure and function. It clarifies what white matter is, emphasizing the role of myelin sheaths in giving the axons a whitish appearance. The script then defines a tract as a bundle of axons in the central nervous system. The anatomy of the spinal cord's white matter is outlined, identifying the dorsal, lateral, and ventral white columns, also known as funiculi. The anterior white commissure, where fiber crossing occurs, is also introduced.

05:00

🔍 Ascending and Descending Tracts in the Spinal Cord

This paragraph delves into the functions of the white matter in the spinal cord, focusing on the ascending and descending tracts. Ascending tracts are responsible for carrying sensory information, while descending tracts are involved in motor information. The script introduces the tract of Lasauer, which plays a role in the pain and temperature pathway, allowing these sensations to ascend or descend one or two spinal cord segments before synapsing in the posterior gray horn. The importance of this pathway is highlighted in relation to the impact of lesions on sensory and motor functions.

10:02

🚀 Descending Motor Tracts in the White Matter

The script provides an in-depth look at the descending motor tracts in the spinal cord's white matter. It identifies the lateral corticospinal tract as the most significant tract in the lateral white column, responsible for voluntary control of skeletal muscles. The rubrospinal tract is also mentioned as another descending motor tract in the lateral column. Moving to the ventral white column, the script describes several tracts including the lateral and medial reticulospinal tracts, the vestibulospinal tract, the tectospinal tract, and the anterior corticospinal tract. The somatotopic arrangement of the lateral corticospinal tract is explained, detailing the organization of motor neurons based on the body regions they supply.

15:02

🌐 Ascending Sensory Tracts in the White Matter

The focus shifts to the ascending sensory tracts within the white matter of the spinal cord. The dorsal column, which contains only ascending tracts, is highlighted with the fasciculus gracilis and fasciculus cuneatus being introduced. These tracts are responsible for carrying sensations related to fine touch, vibrations, and proprioception. The script also covers the ascending tracts in the lateral white column, including the dorsal and ventral spinocerebellar tracts, the spino olivary tract, and the lateral spinothalamic tract, each with specific roles in sensory processing. The anterior white column is noted to contain only one ascending tract, the anterior spinothalamic tract, which carries crude touch and pressure sensations.

20:03

🔬 Basic Functions of White Matter Tracts

This paragraph summarizes the basic functions of the white matter tracts discussed in the script. The dorsal column's fasciculus gracilis and fasciculus cuneatus are associated with sensations from the lower and upper extremities, respectively. The lateral corticospinal tract in the lateral white column is responsible for voluntary muscle control, while the rubrospinal tract influences limb flexors. The spinocerebellar tracts are linked to proprioception, and the spinothalamic tracts are involved in pain and temperature sensations. The anterior white column's descending motor tracts are also mentioned, with their roles in muscle control and the single sensory tract's function in crude touch and pressure sensation.

25:04

🎓 Conclusion on the White Matter of the Spinal Cord

The script concludes with a recap of the white matter of the spinal cord's anatomy and function. It emphasizes the importance of understanding the structure and function of white matter for neurological studies and clinical practice. The video encourages viewers to explore more detailed videos in the neurology playlist for further understanding. The script ends with an invitation for viewers to like, comment, and subscribe for more educational content.

Keywords

💡White Matter

White matter refers to the myelinated axons in the central nervous system, which give it a whitish appearance due to the myelin sheaths. In the context of the video, white matter is crucial as it forms the structural basis for the ascending and descending tracks in the spinal cord, facilitating the transmission of sensory and motor information.

💡Axons

Axons are the long, slender projections of nerve cells, or neurons, that conduct electrical impulses away from the neuron's cell body. The video emphasizes the role of axons in the white matter, where they are insulated by myelin sheaths, allowing for rapid transmission of action potentials.

💡Myelin Sheaths

Myelin sheaths are lipid-protein layers that insulate axons and increase the speed of electrical signal transmission. The video explains that these sheaths are responsible for the white appearance of the white matter and are vital for the fast conduction of nerve impulses.

💡Neuron

A neuron is a cell that is the fundamental unit of the nervous system, transmitting information through electrical and chemical signals. The script describes the basic structure of a neuron, including dendrites, the cell body, and the axon, which are all integral to understanding the function of white matter.

💡Ascending Tracks

Ascending tracks are pathways in the spinal cord that carry sensory information upwards towards the brain. The video script discusses the importance of these tracks in transmitting information related to pain, temperature, touch, and proprioception.

💡Descending Tracks

Descending tracks are pathways that carry motor information downwards from the brain to the spinal cord. The script explains that these tracks are essential for voluntary muscle control and include the corticospinal tracts and other motor pathways.

💡Spinal Cord

The spinal cord is a central nervous system structure that connects to the brain and facilitates communication between the brain and the rest of the body. The video script provides an overview of the spinal cord's white matter, highlighting its role in ascending and descending neural pathways.

💡Funiculus

Funiculus refers to the columns of white matter in the spinal cord, which are named based on their position relative to the gray matter. The script describes the dorsal, lateral, and ventral funiculi, emphasizing their role in the organization of neural pathways.

💡Somatotopic Arrangement

Somatotopic arrangement is the organization of neurons in the nervous system according to the body regions they innervate. The video explains the somatotopic arrangement in the context of the lateral corticospinal and spinothalamic tracts, where the body's sensory and motor information is mapped in a specific sequence.

💡Lateral Corticospinal Tract

The lateral corticospinal tract is a major descending motor pathway that carries signals for voluntary movement from the brain to the spinal cord. The script highlights its role in motor control and its somatotopic organization, with the legs represented laterally and the arms medially.

💡Spinothalamic Tract

The spinothalamic tracts are ascending pathways that carry sensory information related to pain and temperature from the body to the brain. The video script discusses the lateral spinothalamic tract, emphasizing its importance in sensory perception.

Highlights

Introduction to the white matter of the spinal cord and its significance.

Explanation of white matter as myelinated axons giving a whitish appearance.

Definition of a tract as a bundle of axons in the central nervous system.

Anatomy of white matter in the spinal cord, including dorsal, lateral, and ventral white columns.

The role of the anterior white commissure in the crossing of fibers.

The function of white matter in facilitating ascending (sensory) and descending (motor) information.

Description of the tract of Lissauer and its role in the pain and temperature pathway.

Importance of the somatotopic arrangement in the lateral corticospinal tract.

Overview of descending motor tracts in the lateral and ventral white columns.

Functions of the lateral corticospinal tract in voluntary control of skeletal muscles.

Role of the rubrospinal tract in stimulating limb flexors.

Ascending sensory tracts in the lateral white column, including the spinothalamic and spinocerebellar tracts.

The anterior spinothalamic tract's role in carrying crude touch and pressure sensations.

Ascending and descending tracts in the ventral white column, including reticulospinal and vestibulospinal tracts.

Functions of the medial and lateral reticulospinal tracts in supplying extensors and flexors.

Summary of the basic anatomy and function of the white matter of the spinal cord.

Transcripts

all right engineer so in this video

today we're going to talk about

the white matter of the spinal cord and

kind of a basic overview of the

ascending

and descending tracks let's go and get

started all right so when we talk about

the white matter of the spinal cord we

also

first have to talk about what in the

heck is white matter

that's important right so what is white

matter well let's take a teensy little

look here at the

kind of structure of a neuron you guys

know that on the neuron we're going to

have these little extensions called

dendrites right and then we know that

these dendrites are basically

you know the kind of the receptive

region of the neuron then you're going

to have this big structure here with the

nucleus which is called our cell

body and then here we're going to have

the axon

terminal or the terminal bulb whichever

you prefer

and then obviously the length of this

structure here from this point here to

this point here

is our axon the last thing that i want

you guys to remember here is that you

have these little

lipid protein sheets that are

surrounding the axon insulating the axon

allowing for action potentials to be

carried quick down the axon

what are these structures these little

pink little

fat structures hanging on these things

is called your myelin sheaths

these are called your myelin sheaths

now what i want you to remember is

anywhere on a neuron that you see

myelin i want you to remember that is

going to give the neuron a whitish

appearance

so the myelin sheath gives off a white

matter appearance right so when we talk

about white matter i want you to

primarily remember that it is the

myelinated

axons what is white matter it is the

myelinated

axons done

all right so we know what white matter

is the next thing we have to talk about

is another term that i'm going to be

using throughout the course of this

video and that is attract

now if you guys remember what a tract is

imagine here we have a bunch of cell

bodies

okay and then all of these cell bodies

they start giving off their axons and

these axons

travel up as a bundle

these bundles of axons right here this

whole thing here

that is called a track so what is

attract a tract

is a bundle of axons but primarily

in the central nervous system so it is a

bundle

of axons in

the central nervous system boom that's

what i want you to know

all right so we know white matter is we

know what attract is

now let's go over the basic anatomy of

the white matter in the spinal cord

so you know we have different parts of

the spinal cord right and we have we

know here's our gray matter

we've already talked about that well now

we have these columns here that we have

to talk about the white columns or the

funiculi

we already know that we talk about the

white columns based upon their position

in respect to the gray matter so here is

this white column it is

posterior or dorsal to this gray matter

so this is called or dorsal

white column right

or another term is our dorsal funiculus

this right here is our lateral white

column and again

because it's on the side so these are

your lateral white columns and they are

on the sides

of the gray matter so this is called our

lateral

white column or our lateral funiculus

boom all right last one is we have our

ventral

white column and the ventral white

column is anterior

to the gray matter so this is our

anterior

white column beautiful

sometimes there is another structure

that can come up

and you can see this in books and they

kind of sometimes represent it like this

they show these lines crossing there is

a special name for that

we're going to write this down this

right here is called your anterior

white commissure because it's in the

anterior

horn i mean the anterior white column

but this is where crossing of fibers

occur

so whenever fibers come into the dorsal

gray horn and they cross over to the

other side

that is what that structure is so what

is this structure here

it's kind of again in the ventral white

column anterior white column they kind

of represent it with little cross lines

this is called our anterior white

commissure beautiful

all right so we talked about the basic

anatomy of

our white matter the next thing that we

have to talk about

is that this white matter allows for

information

right to either move up so if the

information is moving

up right so let's say that we have

information moving up

right the information that's moving up

through these columns is called

ascending tracks or sending information

and this is usually

sensory information right sensory

information

the other one that we're going to have

to talk about that is also carried in

these white columns

is descending so it's descending

information

and descending information is usually

going to be

motor information so in these tracks

what i want you to remember is that

these tracks can

carry information via their axons up

as a part of your ascending tracks right

and they can carry information down

via the descending tracks that is what i

want you guys to know

okay and what we're gonna do is we're

gonna talk about some of these ascending

and descending tracks

in a basic overview way we have another

we have other videos on our

neurology playlist that cover all of

these tracks in great detail

we're gonna cover this basic all right

so the first kind of white matter track

that we have to talk

about here is actually an interesting

one because it kind of has an ascending

and a descending type of function

this is called the tract

of lasauer

the track of last hour is interesting so

what i want you to remember for the

tractively sour is it is involved in the

pain and temperature pathway

but what it allows for is let me explain

it through kind of a visual here

let's say i have three segments of the

spinal cord right so let's say that here

we have

let's say that this is the t1 segment

this is the

t2 segment and this is our t3 segment of

the

spinal cord now what happens is let's

say that we have a

pain and temperature stimulus so here

we're going to have a receptor right

and it's going to be picking up pain and

temperature sensations

when this receptor picks up that pain

and temperature sensation it carries it

via the sensory neuron

and generally we know that it goes into

the posterior gray horn well actually

that's not completely true

what happens is is this neuron will go

into the right before the posterior gray

horn

right let's imagine here i cut it off

so imagine i cut that portion off right

there

what happens is just before they enter

into that poster gray horn

they enter into this tract and what this

attracts

allows for is it allows for these pain

and temperature fibers

to ascend up one

or two spinal cord segments so you see

how there was a pain and temperature

sensation that were coming from the t3

spinal cord level

it actually won't synapse onto the

posterior gray horn

until it ascends one to two levels then

it'll synapse on the cell bodies here in

the posterior gray horn

cross over and then ascend upwards via

the

spinothalamic tract why is that

important

because if you develop a lesion in the

spinal thalamic tract

let's say at t1 level technically the

loss of pain

in temperatures and stations isn't from

t1 down

it's actually from two levels below

where that lesion is t3 and down

that's why it's important so what i want

you to know about the tractively sour

it allows for pain and temperature

fibers to

ascend or

descend one to two

segments okay before synapsing on the

cell bodies in the posterior gray horn

okay so now we understand the

attractiveness hour let's now move on

and talking about all the different

columns white columns

of dorsal lateral and ventral white

columns all right so we've talked about

white matter we've talked about what

that means to have white matter

or what it means to be white matter we

talked about axons that are bundle of

them in the central nervous system being

attract

right we talked about the anatomy of the

different columns right the dorsal white

column lateral white column

ventral white or another name is

funiculus right so dorsal finiculus

lateral funiculus ventral funiculus

we talked about the basic concept of

descending tracts which is descending

motor information

ascending tracks which is a sensory

information and we talked about this

first kind of weird track called the

tract of lasaur

now what i want to do is i want to take

a cross-section of the spinal cord here

right so i'm taking a cross-section of

the spinal cord

and what i want to do is i want to kind

of draw an imaginary line here

right down the middle of the spinal cord

on one half for kind of diagrammatic

simplicity sake

we're going to talk about all the

descending motor tracks

that are in the spinal cord that are

part of that white matter

and over here on the right side we're

going to talk about all the

ascending or sensory tracks that are

involved

in the white matter of the spinal cord

all right so first things first let's

kind of label these structures

the first one that is out of all of

these motor tracks the most important

is this one right here this big son of a

gun right here this guy right here

is called and it's in the lateral white

column so here we're going to make a

line here to kind of separate

right here is going to separate your

lateral white column from your ventral

white column or anterior white column

so in the lateral white column there's

only two descending

motor tracks what are those two

descending motor tracks

the real big one that i want you to know

is this one and this one is called

the lateral corticospinal

tract okay i want you to remember this

one this is the most important

descending tract in the lateral white

column the

other tract descending track that's also

present in the lateral white column

is called the rubra spinal tract it's

called the rubrow

spinal tract all right beautiful

that covers the descending motor tracks

that are present in the lateral white

column

now let's talk about the descending

motor tracks present in the ventral

white column

okay these ones are actually very

interesting here

so let's cover this from kind of lateral

inwards right

so this first one here this first one

here is called the

lateral reticulo

spinal tract the lateral reticulospinal

tract then if we move

here this is also a reticular spinal

tract but this one's lateral

this one's medial so this guy is called

the

medial reticulo

spinal tract beautiful

okay so we get the lateral reticular

spinal tract the medial reticulospinal

tract

there's another tract right here this

one which is very ventral but again a

little bit more laterally out in this

ventral white column this one is called

your

vestibulo vestibulo

spinal tract

then we move here again a little bit

more immediately we got this son of a

gun right here this is called our

tacto spinal tract

and then the last descending motor track

present in the anterior or ventral white

column

is called our anterior

corticospinal

tract all right beautiful so to recap

descending motor tracks which are

present only in the anterior white

column

are lateral reticular spinal tract

medial reticulospinal tract

vestibulospinal tract tactospinal tract

anterior corticospinal tract and the

lateral white column the descending

motor tracks are the

lateral corticospinal tract and the

rubro

spinal tract all right so the last thing

i want to talk about before we go

starting i'm talking about the basic

overview of the ascending tracks

right make up the white matter of the

spinal cord i want to basically cover

something that's very important

which is called somatotopic

kind of arrangement okay of

this lateral corticospinal tract we

actually have to know this for three

tracks total

the lateral corticospinal the dorsal

column medial meniscus pathway

and the lateral spinal thalamic tract

for right now i want to start with this

lateral corticospinal tract

what i want you to know in simple

way is that in the lateral corticospinal

tract

the legs are laterally that's all i want

you to know

so if we were to kind of put this like

this technically sacral

since the sacral motor supply would be

all the way laterally

then the lumbar then the thoracic

then the cervical if we were to kind of

slice these out like this

this is actually what i want you to know

so whenever we talk about the

somatotopic

arrangement of the lateral corticospinal

tract the descending motor neurons in

the cervical portion are most medially

the descending motor nuts and the

thoracic are just out laterally to that

the lumbar just laterally to that sacral

just laterally to that

why is that important if you develop a

lesion

that only affects this portion of the

lateral corticospinal tract

what areas of the body are going to get

less motor supply or no motor supply

the lower extremities because this is

the sacral and lumbar supply

if you develop a lesion that affects the

medial aspect of the corticospinal tract

the lateral

then you're going to have no motor

supply to the cervical

thoracic regions so now your upper

extremities and trunk

are going to be affected okay that's why

i want you to know that

okay so now we know the descending motor

tracks that make up the white columns

the lateral ventral now let's talk about

the ascending tracts

that are going to be again a component

of the white matter of the spinal cord

all right so we talked about the

descending tracks right which make up

the white mount of the spinal cord now

let's talk about the ascending tracks

that make up the white matter of the

spinal cord so let's start here with our

dorsal column do you guys notice

something

there's no descending tracks in the

dorsal column that's important to

remember only ascending tracks are

present in the

dorsal white column so there are special

names

for these tracks which are present in

the dorsal

column or that dorsal white column if we

talk about

this track which is located more

medially this track which is located

more immediately

this is called the fasciculus

gracilis if we talk about

this tract which is located laterally

in this dorsal white column this is

called our fasciculus

cunietus

that's the first thing i want you to

know okay we're going to talk about

again

the somatotopic arrangement in just a

second let's move on talk about the

other tracks first

so in the dorsal column there's only the

fasciculus gracilis and the fasciculus

cuneinate as fasciculus crystallus

medially fasciculus cunatus

laterally now let's go into this lateral

white column and again we're

going to separate these put a line right

here

okay so this line here is separating the

lateral white column

from the ventral white column in the

lateral white column there's actually a

bunch of ascending tracts

sensory tracts right this one here

on the outer side here kind of in the

dorsal aspect of this lateral white

column

is called the dorsal spino

cerebellar tract so dorsal spinal

cerebellar

tract this tract here which is actually

located more ventrally in this lateral

white column

this is called the ventral

spino cerebellar

tract beautiful

okay now this tract here

is actually a very very important one

this tract right here

is actually going to be the lateral

spinothalamic

tract what is this one the lateral

spinophthalmic

tract beautiful

so we have dorsal spinous cerebellar

tract ventral spinous cerebellar tract

lateral spinothalamic tract one more

tract here which is in the lateral white

column

it's this one right here this son of a

gun here is called the

spino aloe very

tract okay so we have

all of these ascending tracks present in

our lateral white column dorsal spinal

cerebellar ventral spinal cerebellar

spinal olivery

and lateral spinal thalamic tract now

before we cover the somatotopic

arrangements of the lateral

spinothalamic tract

and the dorsal column we're going to

next talk about the ascending tract here

and the anterior white column so

there's only thank goodness only one

ascending track

present within the anterior white column

what is this thing called this is called

our anterior

spinothalamic

tract all right

beautiful now that we've covered that we

have to cover the somatotopic

organization

of the lateral spinothalamic tract and

that dorsal column so let's cover that

first

okay remember what we said for the

lateral corticospinal tract right we

said legs

laterally guess what the lateral

corticospinal tract

and the lateral spinothalamic tract both

legs are laterally

okay so what does that mean that means

that the sacral

sensory supply is going to be most

laterally the

lumbar sensations are going to be a

little bit laterally here

thoracic and then cervical okay

so lateral corticospinal tract and

lateral spinal thymic tract

legs laterally that's what i want you to

remember

okay to finish up with this somatotopic

arrangement

we have to come over here to that dorsal

column now the dorsal column we said has

two areas here right the fasciculus

gracilis

and the fasciculus cunatus i want you to

remember

that the fasciculus gracilis is taking

information

from your lower extremities think about

graceful legs

okay whereas the fasciculus cuniatus is

getting it from the upper

extremities so again if that's the case

then

lower extremities are actually going to

be in here first so we have

sacral then we have lumbar

then we have thoracic and then we have

cervical

so technically the fasciculus gracilis

is taking sensory information from the

lumbosacral area

and the fasciculus cunatus is taking

sensations from the cervical and

thoracic area

boom roasted we hit that let's move on

to the basic functions

of these structures all right so we

already have

detailed videos that cover all these

ascending and descending tracks that we

talked about over here in that

cross section of the spinal cord which

we were kind of pretending is at the

cervical level

what i want you to remember is that

the basic functions the basic functions

of what we're going to cover here if you

want more detail

go watch those videos okay in our

neurology playlist

but dorsal column to give a basic

function of this we have to go back and

talk about that fasciculus

fasciculus gracilis

and the fasciculus cunatus remember

these are picking up

what types of sensations do you guys

remember we've talked about this like a

million times

it's picking up fine touch so like

you're fine a discriminative touch

it's picking up vibrations it's picking

up

proprioception all of those sensations

are being carried

via a specific pathway called the dorsal

column medial lemniscus pathway right

we have a video in more detail on that

what i want you to remember is that all

that fine discriminative touch

vibrations proprioceptions carried from

the fasciculus gracilis

is from t6 and below

whereas all the fine touch vibrations

proprioception discriminative touch

from the fasciculus cuniatus is going to

be from the t5 spinal cord level

and above that's all i want you to know

okay

lateral white column okay again dorsal

dorsal column just to recap

was there any motor pathways any

descending tracks no

only ascending tracks okay ladder white

column

there was motor tracks right we said

that the big one that i wanted you to

know was that

lateral corticospinal tract right so

that lateral

corticospinal tract what do we need to

know about this one

this will supply what again this is 85

of that corticospinal tract again it

decays at the pyramids right

but the main thing that i want you to

know is that this will

stimulate the lower motor neurons

right to allow for voluntary

control of

skeletal muscles that's all i want you

to know about this one again you want

more detail

on this go watch our video on that

lateral corticospinal tract

it stimulates the lower motor neurons

and again that allows for voluntary

control of our skeletal muscles for

fine-tuned type of activities

the other motor track that was present

within our lateral white column you guys

remember

it was the rubra spinal tract that was

our rubra

spinal tract now the rubra spinal tract

its basic function is it is also going

to stimulate lower motor neurons

but primarily for the flexors

okay so it's only going to pretty much

stimulate your

limb flexors that was all of the

descending tracts in the lateral white

column what were some of the ascending

tracts in the lateral white column do

you guys remember

one of them was the dorsal

spinocerebellar tract spino cerebellar

tract now the dorsal spinal cerebellar

tract what did it pick up

it picked up proprioception again for

like the

millionth time what is proprioception it

is the

three-dimensional position of our our

muscles right our tendons

our ligaments our joint capsules all

that stuff in a three-dimensional space

it sends that and picks up

proprioceptive sensations

from what areas of the body from c8 to

l2 via clark's column what was the other

white matter track there

the other one was called the ventral

spino

cerebellar tract and that was

also picking up what proprioceptive

sensations

and that proprioceptive sensations were

coming from what areas of the body

this was coming from from l2 to

the coccygeal one area of the spinal

cord

what was another white matter tract that

was called the

spino aloe very tract

and the spinal olivery tract was

important for what again it picks up

proprioception

but it sends this information to who

what structure

the inferior olives so it sends it again

to the inferior

olives and then the inferior olives will

send this to your

cerebellum these are called your

climbing fibers

okay the last one which we talked about

was the

lateral spinothalamic

tract and the lateral spinothalamic

tract we said that this one is going to

carry what kinds of sensations

primarily pain and

temperature sensations beautiful

all right so last one venture white

column we had all those

tons of motor tracks present right we

had what which ones did we talk about

first we said we had that lateral

reticulospinal oh what is another name i

should have said this before

what is another name for the lateral

reticulospinal tract

because remember there was two

reticulospinal tracts one's from the

pons

and then one's from the medulla lateral

medulla

okay so technically this is actually the

fibers coming from the

medulla so the medullary reticulospinal

tract

this one from medullo reticulospinal

tract is primarily for

flexors so all i want you to know is

that this stimulates

flexors done the other one we said was

the

medial reticulo

spinal tract oh

so what's the other one then this one

was the medulla the other one was the

pontine reticulospinal tract

so the medial reticular spinal tract is

also called the

pontine reticulospinal tract

this primarily supplies extensors

that's all i want you to know the other

one that we talked about is called the

vestibulo spinal vestibulo

spinal tract and the vestibulospinal

tract i want you to know that this one

is primarily stimulating

extensors your anti-gravity muscles

right the other one there's so many of

these dang things

the tectospinal tract the tectospinal

tract

i want you to know that that is going to

be sending information for

movement of the head and

neck and eye movements

boom roasted all right the last one here

is your ventral or anterior

corticospinal

tract right so it's the same thing

anterior ventral corticospinal tract

that was also going to stimulate lower

motor neurons

for voluntary

voluntary muscle control what type of

muscle

skeletal muscle control boom

that covered all of the descending

tracks there was

one sensory tract in this one it was the

interior spinothalamic

tract and this one carried crude

touch and pressure

sensations boom roasted

we hit all of them so now we know the

basic anatomy and the basic function of

the white matter of the spinal cord

all right ninja nurse so in this video

we talk in pretty decent detail about

the white matter of the spinal cord

its structure and its function i hope

this made sense hope you guys did like

it if you guys did

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alright ninja nerds we love you we thank

you we appreciate you and as always

until next time

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you