シャドーイング練習: Embryology of the Nervous System - 動画で英語スピーキングを学ぶ

練習モードを選ぶ

各モードは全画面の練習ルームで開きます。

186 文

文が短すぎたり長すぎる場合は、Editをタップして調整してください。

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.

アプリをダウンロード

流暢に話すために必要なすべて

AI発音採点文ごとに採点

IPA練習すべての音をマスター

単語学習自分の単語帳を作る

単語ゲーム遊びながら覚える

QRをスキャン

Download on theApp Store Get it onGoogle Play

同じチャンネル

Retinal Artery Occlusion vs. Retinal Vein Occlusion

Daily ConversationUniversity Students

Lymphoma

IELTS PrepTOEFL PrepUniversity Students

FOR YOU

このレッスンの語彙とスピーキングのポイント

このC1レベルのスピーキングレッスンは、動画「Embryology of the Nervous System」を教材にしています。繰り返し出てくる語は次のとおりです：neural, rise, bifida, spina, ectoderm。この動画には、シャドーイング用の文が186文、単語が2553語あります。音声の長さは14:48です。話す速さは1分あたり約173語で、日常会話に近い自然なペースです。英語の頻出3,000語に含まれる単語は77%だけなので、語彙は難しめです。

この動画の重要語彙

動画の中で特に難しい単語15語を、発音と意味つきで紹介します。

単語	発音	意味
fold 動詞	/ˈfəʊld/	折る, 畳む
vesicle 名詞	/ˈvɛsɪkəl/	小胞
embryology 名詞		発生学, 胎生学
cord 名詞	/ˈkoɹd/	縄
ventricle 名詞	/ˈvɛn.tɹɪk.əl/	心室
derivative 名詞	/dɪˈɹɪvətɪv/	派生
diencephalon 名詞	/ˌdaɪ̯.ənˈsɛfəlɑn/	間脳
medulla 名詞	/məˈdulə/	髄
pathology 名詞	/pəˈθɒləd͡ʒi/	病理学
hemisphere 名詞	/ˈhɛmɪsfɪə/	半球
blastula 名詞	/ˈblæst͡ʃələ/	胞胚
mnemonic 名詞	/nəˈmɑnɪk/	語呂合わせ, 記憶法
cavity 名詞	/ˈkæv.ɪt.i/	腔
crest 名詞	/kɹɛst/	とさか
congenital 形容詞	/kənˈdʒɛnɪt(ə)l/	先天的

動画に出てくる句動詞

単語	発音	意味
come out 動詞	/ˌkʌm ˈaʊt/	出る
go down 動詞		降りる, 降下する

この動画の文法

話し手がよく使っている文型を、動画の実際の表現とともに紹介します。

文型	動画での表現
受動態 be + 過去分詞 — 誰がするかより、何が起きるかに焦点を当てる	is shown · is referred · was derived
関係詞節 who / which + 節 — 人や物について情報を加える	ectoderm, which is · plate, which is · tube, which was
現在完了形 have/has + 過去分詞 — 過去の出来事が今も関係している	I've just described

注意したい発音

話し手はyou're, they'll, I'mなど、短縮形や弱形を36回使っています。聞こえたとおりの短い形で発音しましょう。

「th」の音: pathology /pəˈθɒləd͡ʒi/, thalamus /ˈθæləməs/
「sh」と「zh」の音: protrusion /pɹəˈtɹuːʒən/, neuralation /ˌn(j)uːɹəˈleɪʃən/, manifestation /ˌmænɪfɛˈsteɪʃən/, differentiate /dɪf.əˈɹɛn.ʃi.eɪt/
長い単語（アクセントの位置に注意）: telencephalon /ˌtɛlənˈsɛfələn/, mesencephalon /ˌmɛzənˈsɛfələn/, derivative /dɪˈɹɪvətɪv/, anencephaly /æn.ɪnˈsɛ.fə.lɪ/, diencephalon /ˌdaɪ̯.ənˈsɛfəlɑn/

日本語話者が苦手な音：

/r/ と /l/ の区別 — /l/ は舌先を歯茎につけ、/r/ はどこにもつけない: neural /ˈnʊɹəl/, ventricle /ˈvɛn.tɹɪk.əl/, cerebral /səˈɹi.bɹəl/, laterally /ˈlæ.tə.ɹə.li/, neuralation /ˌn(j)uːɹəˈleɪʃən/
/v/ — /b/ にならないように、上の歯を下唇に当てる: vesicle /ˈvɛsɪkəl/, ventricle /ˈvɛn.tɹɪk.əl/, derivative /dɪˈɹɪvətɪv/, cavity /ˈkæv.ɪt.i/, vertebra /ˈvɝ.təb.ɹə/
/f/ — 「フ」ではなく、上の歯と下唇で出す: fold /ˈfəʊld/, telencephalon /ˌtɛlənˈsɛfələn/, mesencephalon /ˌmɛzənˈsɛfələn/, anencephaly /æn.ɪnˈsɛ.fə.lɪ/, diencephalon /ˌdaɪ̯.ənˈsɛfəlɑn/

この動画での練習方法

まず声を出さずに動画を最後まで聞き、知らない単語をメモします。
まず0.75倍速で一文ずつシャドーイングし、慣れてきたら通常の速度に戻します。
自分の声を録音して元の音声と比べます。fold, vesicle, embryologyなどの単語に特に注意しましょう。

シャドーイングとは？英語上達に効果的な理由

シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。

シャドーイングのやり方: ステップ別の完全ガイドを読む →

シャドーイング練習: Embryology of the Nervous System - 動画で英語スピーキングを学ぶ

練習モードを選ぶ

アプリをダウンロード

同じチャンネル

Retinal Artery Occlusion vs. Retinal Vein Occlusion

Lymphoma

おすすめ動画

The Nervous System Explained Simply | Brain, Neurons & Signals

Stem Cells

Human Anatomy Eye

Biggest Breakthroughs in Biology and Neuroscience: 2025

Micro-Biology: Crash Course History of Science #24

Cerebral Vascular Anatomy And Imaging

Introduction to Hematology

How Depression Affects The Brain - Yale Medicine Explains

Why don't you remember being a baby?

The Worm with 4 Nobel Prizes

The 600 Million Year Story of the Human Brain | FULL DOCUMENTARY

🏥 Locating Organs with Surface Landmarks: Do You Know Where Key Organs Are?