Shadowing Practice: Embryology of the Nervous System - Learn English Speaking with Video

In this video, we'll talk about nervous system embryology.

Let's get started.

The important thing to note here is that you have something called a blastula, and over time, that blastula will sort of fold into itself, shown here in red.

In doing so, the blastula will give rise to a blastopor.

For the purposes of nervous system embryology, we don't really care about the blastopor because that goes on to form a cavity for the GI system.

But what we do care about is that after the blastula folds into itself, we get the formation of three germ layers.

Those three germ layers are the endoderm, the mesoderm, and the ectoderm.

And in talking about nervous system embryology, we are particularly focused on the ectoderm.

The ectoderm is what goes on to become the entire nervous system.

So here's where we are right now.

We've got an ectoderm shown in purple, mesoderm shown in orange, and I'm not even showing you the endoderm

because it's kind of irrelevant for the purposes of this embryology discussion.

So between where the mesoderm sits, you get the development of something called the nodochord.

And the nodochord will secrete growth factors, and those growth factors will seep out and act on the ectoderm.

Those growth factors are going to tell the ectoderm to start to differentiate into a neural plate.

Now, as that neural plate begins to form in the center, it pushes out the ectoderm laterally.

The combination of the ectoderm moving laterally and the growing neural plate forming in the medial section,

this is all referred to as the neuroectoderm because the ectoderm is giving rise to all of the nervous system.

Now, what's going to start to happen here is that the neural plate will sort of start to fold over.

And as it grows and continues to fold, it's going to push the ectoderm up and out.

And it's going to look like this.

So that growing, if we were on this side, that growing neural plate starts to fold.

And then the ectoderm forms these folds that will curve out at the top.

Now between the ectoderm, which is shown in purple and is continually moving out laterally and folding over.

And the neural plate, which is shown in teal, which is growing in a sort of circular fashion,

that area in between them shown here with the brown circles, that is going to ultimately give rise to neural crest.

So again, in teal, we have neural plate.

In brown, we have the tissue that will ultimately become neural crest.

And in purple, we have the ectoderm that's folding out laterally, and this is referred to as the neural folds.

Now as these neural folds start to invaginate, they sort of pinch medially,

and as this happens, the neural plate area of the neural folds will move toward the midline.

And so when all of these motions are happening in 3D in real time, you're slowly going to get the formation of a circular object.

And what we end up with is a neural tube, which was derived from the neural plate, the neural crest, which sits right above it,

which was the area in between the ectoderm of the neural fold and the neural plate of the neural fold.

And then we've got the remnants of the ectoderm up on the top.

And so this entire process that I've just described is what's known as neurulation.

And on your exams, neurulation is is really the meat of all of your questions.

So if they're going to ask you a black

and white question about embryology in terms of how these things are folding and moving, it's probably going to be about neuralation.

So here's where we are.

And let's pause for a moment

because what becomes really high yield is not only knowing how

neuralation works in terms of the neural ectoderm giving rise to the neural crest and the neural tube,

but also pathology that can occur if this doesn't happen the way that it's supposed to.

So embryology, if you want to really be a reductionist here

and think about this in a really simple and stupid kind of way.

Embryology is normal, but when embryology doesn't occur normally, you get pathology and congenital abnormalities.

So let's talk about spina bifida.

Spina bifida in general refers to varying degrees of congenital abnormalities

that result from the failure of the neural tube to close caudally.

In other words, if neuralation, as I've just described it, doesn't occur the way that it's supposed to, one of the manifestations of that is spina bifida.

So let's go and talk about the three different types of spina bifida.

We'll start with spina bifida occulta.

Spina bifida occulta, there is no protrusion of spinal contents.

Okay, so look at the image below.

There's three different types of spina bifida.

There's spina bifida occulta, spina bifida with meningocele, and spina bifida with myelomeningocele.

And as you move from left to right across these three different types, it gets more severe.

So in spina bifida occulta, no protrusion of the spinal contents will be coming out through the vertebrae.

And in this case, alpha fetal protein, when it's measured, will be normal.

You would only see elevated levels of alpha fetal protein

if there is an open hole in the low back through the vertebrae, because that's where the AFP will leak out, and that's where it's measured.

Now in these patients with spina bifida occulta, you could see a tuft of hair or a sacral dimple right in

that area of the low back where in more severe versions of spina bifida, you would see protrusion.

But again, in occulta, it's called occulta because it's occult.

You don't see it.

It's kind of there hidden with no protrusion.

So this is the most benign version of spina bifida.

Now in spina bifida with meninges seal, we do see protrusion of the meninges.

And because we're seeing protrusion and because there's that opening in the low back, levels of alpha-fetoprotein will be increased if measured.

And in these patients, the spinal cord is undamaged.

And that's important to know because even though you have protrusion of something, it's just the meninges.

It's not the spinal cord itself.

So look in the image, the spinal cord is still in the canal where it's supposed to be.

It's just the meninges that are protruding through.

Lastly, we have spina bifida with myelomeningocele.

And this is the most severe type of spina bifida.

In myelomeningocele, you see protrusion of both the meninges and the spinal cord.

And because of this, because there's a hole in the low back, fluid can leak out.

So if measured, you'll see increased levels of alpha-feta protein.

What's very important to know for exams is that spina bifida with myelomeningocele is highly associated with Chiari type 2 malformations.

Now these are the three different types of spina bifida, and I want to show you this summary chart so that you can keep all of this straight.

Again, occulta is occult.

It's not protruding through.

It's just there in the low back.

So there's no protrusion and AFP is normal.

In these patients, you could see a tuft of hair or sacral dimpling.

In spina bifida with meninges, it's meninges.

It's just meninges.

So protrusion of the meninges through the low back, there's a hole there, so AFP will be increased.

It's just meninges, so the spinal cord is fine.

It's just the meninges.

In spina bifida with myelomeningocele, it's myeloplus meningoceles.

So So it's spinal cord, mylo, plus meningo, plus meninges.

So it's protrusion of meninges and spinal cord.

There's a hole in the low back, so AFP is increased.

And this is highly associated with Chiari 2 malformations.

So these are the three different types of spina bifida.

Again, this pathology occurs if neurulation does not happen normally.

100

The other pathology I want to talk about is anencephaly.

101

And this is a really sad and unfortunate congenital malformation where you have partial absence of the brain,

102

calvaria, or skull because the neural tube didn't close at the cephalic end.

103

So spina bifida is at the other end, not the cephalic end.

104

But anencephaly is the cephalic end, right?

105

So it's up at the top where the head would be.

106

So in anencephaly, you can, you really see incompatible with life, right?

107

So this isn't compatible with survival.

108

If, if, if a developing baby has anencephaly, then unfortunately it's, it's either going to be stillborn or it will probably pass within a few hours of birth.

109

And in anencephaly, you're going to see increased levels of AFP and polyhydramnios.

110

Again, there's a hole up where the head should be, and that allows the leakage of fluid.

111

So we'll the increased AFP and polyhydramnios.

112

Now again, this is what we were talking about.

113

So we were talking about neurulation and this is where we ended.

114

And what's important to note now is that at that neural tube, at the top of the neural tube where that black star is shown,

115

this is what's going to lead to primary vesicle formation.

116

So let's talk about that now.

117

So primary vesicle formation is the formation of the developing nervous system.

118

And the first thing that's going to form are three primary vesicles.

119

So we have the prosencephalon, which gives rise to the forebrain, the mesencephalon, which gives rise to the midbrain,

120

and the romencephalon, which gives rise to the hindbrain.

121

Again, all of this is derived from the top part of the neural tube.

122

Now each of these three areas shown in different colors for your convenience gives rise to more and more structures.

123

So the prosencephalon will give rise to both the telencephalon and the diencephalon.

124

The mesencephalon will give rise to the mesencephalon, so that's pretty easy to memorize.

125

The romencephalon will give rise to both the metencephalon and the myelencephalon.

126

Now, I'm going to pause for a moment.

127

I have another video on my channel that goes through this and gives you mnemonics to remember all of this.

128

So I'm just describing the embryology here, but if you want the mnemonic for how all of this is easily memorized, then see that other video.

129

So now we have the telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon.

130

And these are going to give rise to neural derivatives, okay?

131

So just to keep things stupid and simple, we talked about these are your primary vesicles.

132

They give rise to secondary vesicles.

133

Here are your secondary vesicles that will give rise to neural derivatives, okay?

134

So the telencephalon will give rise to the cerebral hemispheres and the globus pallidus, and the diencephalon will give rise to the thalamus and the hypothalamus.

135

The mesencephalon, the metencephalon, and the myelencephalon give rise to midbrain, pons, cerebellum, and medulla.

136

And if you're a little confused right now in terms of how you're supposed to learn all of this

137

and keep all of this straight, aside from using my mnemonic, which I have in my other video on this topic.

138

Really, if you know neuroanatomy, this should make sense because the telencephalon is at the top, the myelencephalon is at the very bottom,

139

and then you've got varying degrees of these vesicles in between.

140

And so from top down, if you know where the cerebral hemispheres are, where the globus pallidus is, thalamus, hypothalamus, as I go down this list,

141

et cetera, et cetera, I'm moving from top to bottom.

142

So if you know that the telencephalon is at the top and the myelencephalon is at the bottom, and then you're asked which one gives rise to the medulla, well, in your head, you could be like,

143

I know that the medulla is at the bottom or the base of the brain.

144

So which of the secondary vesicles is at the bottom or is at the base?

145

And so myelencephalon gives rise to medulla.

146

Conversely, if you're asked what gives rise to the cerebral hemispheres, in your head you could be like,

147

well, I know that the cerebral hemispheres are sort of like at the outside or at the top of the brain,

148

and so it's probably the topmost secondary vesicle, so it's probably telencephalon.

149

And so it's easier to guess if you have a rough idea of the general neuroanatomy from top to bottom.

150

And that's a theme that we'll carry over into the next slide as well.

151

So these neural derivatives each give rise to cavities or where CFS or CSF flows.

152

That's a tongue twister.

153

So the telencephalon goes to cerebral hemispheres and globus pallidus.

154

That gives rise to the lateral ventricle.

155

The diencephalon gives rise to the thalamus and hypothalamus.

156

That gives rise to the third ventricle.

157

Mesencephalon gives rise to midbrain that creates the cerebral aqueduct.

158

Metencephalon, pond cerebellum, that gives rise to the upper part of the fourth ventricle.

159

And the myelencephalon gives rise to the medulla, that gives rise to the lower part of the fourth ventricle and the central canal.

160

So just like we saw with the neural derivatives, if you have a rough understanding of top to bottom neural anatomy,

161

you can make a very educated guess about which ventricle or which cavity is formed from which structure.

162

And so here is an image of how CSF flows from top to bottom.

163

So lateral ventricle to third ventricle to cerebral aqueduct to fourth ventricle to central canal.

164

And top to bottom, you see on this slide, it's identical to this slide.

165

So telencephalon at top, then diencephalon, mesencephalon, metencephalon, myelencephalon, top to bottom.

166

And so keeping this color coded top to bottom, we go lateral to third, cerebral, fourth, central.

167

Again, the takeaway here is that you can either memorize it, you can learn a mnemonic from my other video,

168

or you can just, if you know neuroanatomy, work top to bottom.

169

And this should all make sense.

170

So those are the derivatives.

171

So here's what we talked about.

172

The top part of the neural tube gave rise to primitive vesicles or primary vesicles.

173

Those gave rise to secondary vesicles.

174

Those gave rise to neural derivatives and those gave rise to cavities.

175

So that's what we just talked about.

176

That was all from the top part of the neural tube.

177

The bottom part of the neural tube, that gives rise to the spinal cord.

178

Not really a lot to talk about there.

179

Just know that the bottom part of the neural tube becomes the spinal cord.

180

Top part of the neural tube basically becomes everything else.

181

So I flew through that, but that is nervous system embryology.

182

Again, I'd probably re-watch this video once or twice because it is a complex topic, but at the end of the day, if they're going to ask you questions about this,

183

they'll either ask you about how neuralation works, they'll ask you about pathology, you know, spina bifida, that sort of thing.

184

They'll ask you about the derivatives from the top of the neural tube, or they'll just be really, really nice to you and they'll say, where does the spinal cord come from?

185

And that's the bottom of the neural tube.

186

Good luck.

📺 Mismo canal

Lymphoma

IELTS PrepTOEFL PrepUniversity Students

✨ Recomendar Video

52 oraciones

Vocabulario y notas de pronunciación para esta lección

Esta lección de conversación de nivel C1 se basa en el vídeo “Embryology of the Nervous System”. Las palabras que más se repiten: neural, rise, bifida, spina, ectoderm. Este vídeo tiene 186 frases y 2553 palabras para practicar shadowing. La parte hablada dura 14:48. El hablante habla a un ritmo natural de unas 173 palabras por minuto, cercano a una conversación cotidiana. Solo el 77 % de las palabras está entre las 3.000 más comunes del inglés, por lo que el vocabulario es exigente.

Vocabulario clave de este vídeo

Las 15 palabras más avanzadas del vídeo, con su pronunciación y significado:

Palabra	Pronunciación	Significado
neural adjetivo	/ˈnʊɹəl/	neural
ectoderm sustantivo		ectodermo
fold verbo	/ˈfəʊld/	plegar, doblar
meninx sustantivo	/ˈmi.nɪŋks/	meninge
vesicle sustantivo	/ˈvɛsɪkəl/	vesícula
spinal adjetivo	/spaɪ.nəl/	espinal, vertebral
embryology sustantivo		embriología
cord sustantivo	/ˈkoɹd/	cuerda, cordón
telencephalon sustantivo	/ˌtɛlənˈsɛfələn/	telencéfalo
ventricle sustantivo	/ˈvɛn.tɹɪk.əl/	ventrículo
cerebral adjetivo	/səˈɹi.bɹəl/	cerebral
derivative sustantivo	/dɪˈɹɪvətɪv/	derivado
anencephaly sustantivo	/æn.ɪnˈsɛ.fə.lɪ/	anencefalia
diencephalon sustantivo	/ˌdaɪ̯.ənˈsɛfəlɑn/	diencéfalo
medulla sustantivo	/məˈdulə/	médula, medula

Phrasal verbs que vas a escuchar

Palabra	Pronunciación	Significado
come out verbo	/ˌkʌm ˈaʊt/	revelarse, salir a la luz
go through verbo		atravesar
move out verbo		mudarse de acá, independizarse

Gramática en este vídeo

Las estructuras que más usa el hablante, con las palabras exactas del vídeo:

Estructura	En el vídeo
Voz pasiva be + participio pasado — importa lo que ocurre, no quién lo hace	is shown · is referred · was derived
Oraciones de relativo who / which + oración — información extra sobre una persona o cosa	ectoderm, which is · plate, which is · tube, which was
Present perfect have/has + participio pasado — una acción pasada que sigue importando ahora	I've just described

Pronunciación a tener en cuenta

El hablante usa 36 contracciones y formas reducidas, como you're, they'll, I'm. Dilas en su forma corta, tal como las oyes.

Los sonidos de “th”: pathology /pəˈθɒləd͡ʒi/, thalamus /ˈθæləməs/
Los sonidos de “sh” y “zh”: protrusion /pɹəˈtɹuːʒən/, neuralation /ˌn(j)uːɹəˈleɪʃən/, manifestation /ˌmænɪfɛˈsteɪʃən/, differentiate /dɪf.əˈɹɛn.ʃi.eɪt/
Palabras largas — cuida el acento: telencephalon /ˌtɛlənˈsɛfələn/, mesencephalon /ˌmɛzənˈsɛfələn/, derivative /dɪˈɹɪvətɪv/, anencephaly /æn.ɪnˈsɛ.fə.lɪ/, diencephalon /ˌdaɪ̯.ənˈsɛfəlɑn/

Sonidos difíciles para hispanohablantes:

s + consonante al inicio — sin añadir una “e” delante: spina /ˈspaɪ.nə/, spinal /spaɪ.nəl/, stillborn /ˈstɪlbɔː(ɹ)n/
/v/ — no es /b/: los dientes tocan el labio inferior: vesicle /ˈvɛsɪkəl/, ventricle /ˈvɛn.tɹɪk.əl/, derivative /dɪˈɹɪvətɪv/, cavity /ˈkæv.ɪt.i/, vertebra /ˈvɝ.təb.ɹə/
/z/ — sonora, no /s/: mesencephalon /ˌmɛzənˈsɛfələn/, memorize /ˈmɛm.əˌɹaɪ̯z/, pause /pɔːz/

Cómo practicar con este vídeo

Escucha el vídeo entero una vez sin hablar y anota las palabras que no conoces.
Empieza a velocidad 0,75×, haz shadowing frase por frase y vuelve a la velocidad normal cuando te resulte fácil.
Grábate y compara con el original, prestando atención a palabras como neural, ectoderm, fold.

¿Qué es la Técnica de Shadowing?

Shadowing es una técnica de aprendizaje de idiomas respaldada por la ciencia, desarrollada originalmente para la formación de intérpretes profesionales y popularizada por el políglota Dr. Alexander Arguelles. El método es simple pero poderoso: escuchas audio en inglés nativo y lo repites en voz alta de inmediato, como una sombra que sigue al hablante con solo 1-2 segundos de retraso. A diferencia de la escucha pasiva o los ejercicios de gramática, el shadowing obliga a tu cerebro y músculos de la boca a procesar y reproducir simultáneamente patrones de habla reales. Las investigaciones muestran que mejora significativamente la precisión de la pronunciación, la entonación, el ritmo, el habla conectada, la comprensión auditiva y la fluidez al hablar, convirtiéndola en una de las metodologías más efectivas para la preparación del IELTS Speaking y la comunicación en inglés en el mundo real.

Técnica de shadowing: lee la guía completa paso a paso →

Shadowing Practice: Embryology of the Nervous System - Learn English Speaking with Video

Lymphoma

Human Anatomy Eye

Could Humans Evolve Flight?

Stem Cells

The Nervous System Explained Simply | Brain, Neurons & Signals

MRI-Negative Epilepsy

Review of Musculoskeletal System (Bones & Muscles) - Biology Lectures Series

The Insane Biology of: The Octopus

Endocrine System

The medicine myth | Denis Noble, Nessa Carey, Guy Brown

The Neuroscience of Creativity

Cerebral Vascular Anatomy And Imaging

Homeostasis - How Your Body Keeps its Balance - Physiology Series