تدريب Shadowing: Introduction to neural cell types | Organ Systems | MCAT | Khan Academy - تعلم التحدث بالإنجليزية عبر الفيديو

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In this video, I want to introduce the different types of neural cells.
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The word neural, or the prefix neuro, just refers to the nervous system, so that neural cells are cells of the nervous system.
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Neural cells work with all the other cell types of the
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body to produce the amazing range of functions of the nervous system, including consciousness, social interactions, cognition,
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emotion, movement, sensory perception, and regulation of other functions such as circulation, respiration, and digestion.
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Neural cells are divided into two big categories.
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The first are neurons, which were traditionally called nerve cells.
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And the second are glia.
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Now these can also be called neuroglia or glial cells.
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That all means the same thing.
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Neurons are named from a Greek word for nerve, while glia are named from a Greek word for glue because they are once thought to do little except glue neurons together.
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The structure of the nervous system is divided into two main parts.
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The first part is mainly made up of the brain in the head and the spinal cord in the spine.
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And this part of the nervous system is called the central nervous system.
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The other part of the nervous system is called the peripheral nervous system.
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And that's made up mostly of nerves, these long stringy structures that come out of the brain and the spinal cord.
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And they go all over the body, like down into the arms and down into the legs and into every part of the body.
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And we'll cover a lot more detail about neuroanatomy in other videos, but I just need to bring up the central
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and peripheral nervous system because the neural cells are divided up differently amongst the different systems.
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Calling neurons nerve cells is a little problematic
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because these structures in the peripheral nervous system called nerves are made up of neurons, but they also contain glial cells,
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and they contain a number of other cells that aren't neural cells at all.
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However, you'll often hear people refer to neurons as nerve cells because that was the traditional name for them.
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Neurons are found both in the central nervous system, the brain and the spinal cord, and the peripheral nervous system, in the nerves.
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But the different types of glial cells are found only in one or the other.
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Most neural cells are derived from populations of cells called neural stem cells or neural crest cells.
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And both of those cell types arise early in development in the part of the embryo called the ectoderm.
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Most neurons in glia found in the central nervous system are derived from neural stem cells,
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while most neurons in glia found in the peripheral nervous system are derived from neural crest cells.
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Now we'll go into a lot more detail about what neural stem cells are
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and neural crest cells in other videos when we cover development of the nervous system.
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Most types of both neurons and glia share some structural features of the way their cell is shaped.
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Most of them have a main part to their cell called the soma, or the cell body, that contains the nucleus and most of the organelles.
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Coming out of the soma, most of these cell types have processes, long, thin extensions that come out of the soma.
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And the processes of the different neural cells vary in number and in length and thickness and degree of branching, because some of them will be unbranched,
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and some of them will have processes that branch, sometimes a little and sometimes a lot.
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They will also vary a lot in the terminal structures at the end of their processes
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and the function of these structures and the processes.
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The function of neurons is to process and transmit information, and the function of glia is to support them in a variety of ways.
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There are many structural and functional types of both the neurons and the glia, And there are large numbers of these cells making up the nervous system.
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There are billions of neurons that form trillions of connections in the adult human nervous system.
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And there are even more glia than there are neurons.
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In subsequent videos, we'll go over the most common glia, which are astrocytes, microglia, ependymal cells, oligodendrocytes, and Schwann cells.
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There are also less common glia, such as satellite cells and olfactory and sheathing cells.
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But we'll just go over the most common types here.

تنزيل التطبيق

كل ما تحتاجه للتحدث بطلاقة

تقييم النطق بالذكاء الاصطناعيتقييم كل جملة
تدريب IPAأتقن كل صوت
المفرداتابنِ رصيدك من الكلمات
لعبة المفرداتتعلّم أثناء اللعب

نفس القناة

FOR YOU

فيديو موصى به

المفردات وملاحظات التحدث لهذا الدرس

يحتوي هذا الفيديو على 45 جملة و742 كلمة للتدرب على الترديد. مدة الكلام 4:10. يتكلم المتحدث بسرعة طبيعية، نحو 178 كلمة في الدقيقة، قريبة من المحادثة اليومية. 77% فقط من الكلمات ضمن أكثر 3,000 كلمة شيوعًا في الإنجليزية، فالمفردات صعبة نسبيًا.

أهم المفردات في هذا الفيديو

15 كلمة من الفيديو تستحق التعلّم، مع النطق والمعنى:

الكلمةالنطقالمعنى
nerve اسم/nɝv/عَصَب
divide فعل/dɪˈvaɪd/قَسَّمَ
cord اسم/ˈkoɹd/خَيْط, حَبْل
spinal صفة/spaɪ.nəl/فِقْرِيّ, فِقَرِيّ
derive فعل/dɪˈɹaɪv/استمد
refer فعل/ɹɪˈfɜː/أَشَارَ
glue اسم/ɡlu/غِرَاء, لِزَاق
thin صفة/ˈθɪn/رَفِيع, رَقِيق
regulation اسم/ˌɹɛɡjʊˈleɪʃən/تَنْظِيم
introduce فعل/ˌɪntɹəˈdus/قَدَّمَ
satellite اسم/ˈsætəlaɪ̯t/قَمَر, تَابِع
interaction اسم/ˌɪn.təˈɹæk.ʃən/تَآثُر, تَفَاعُل
emotion اسم/ɪˈməʊ.ʃən/عَاطِفَة, عَوَاطِف
perception اسم/pɚˈsɛpʃ(ə)n/اِدْرََاك حَسِّيّ
consciousness اسم/ˈkɑnʃəsnəs/وَعْي, شُعُور

نطق يحتاج إلى انتباه

يستخدم المتحدث 6 من الصيغ المختصرة، مثل we'll, aren't, you'll. انطقها بصيغتها القصيرة كما تسمعها.

  • أصوات “th”: thin /ˈθɪn/, thickness /ˈθɪknəs/, sheath /ʃiθ/
  • أصوات “sh” و“zh”: structural /ˈstɹʌk(t͡)ʃəɹəl/, extension /ɪkˈstɛnʃən/, regulation /ˌɹɛɡjʊˈleɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, emotion /ɪˈməʊ.ʃən/
  • الكلمات الطويلة — انتبه لموضع النبر: peripheral /pəˈɹɪf(ə)ɹ(ə)l/, regulation /ˌɹɛɡjʊˈleɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, differently /ˈdɪf.ə.ɹənt.li/, traditionally /tɹəˈdɪʃ.ə.nə.li/

كيف تتدرب بهذا الفيديو

  1. استمع إلى الفيديو كاملًا مرة واحدة دون أن تتكلم، ودوّن الكلمات التي لا تعرفها.
  2. ابدأ بسرعة 0.75×، وردّد جملة جملة، ثم عُد إلى السرعة العادية عندما يصبح الأمر سهلًا.
  3. سجّل صوتك وقارنه بالأصل، مع الانتباه إلى كلمات مثل nerve, divide, cord.

القواعد في هذا الفيديو

أكثر التراكيب التي يستخدمها المتحدث، مع العبارات نفسها من الفيديو:

التركيبفي الفيديو
المبني للمجهول be + اسم المفعول — التركيز على ما يحدث لا على من يفعلهare divided · be called · are named
جمل الوصل who / which + جملة — معلومة إضافية عن شخص أو شيءneurons, which were · glia, which are

ما هي تقنية التظليل الصوتي؟

التظليل الصوتي (Shadowing) تقنية تعلم لغة مدعومة علمياً، طُورت أصلاً لتدريب المترجمين الفوريين المحترفين. الطريقة بسيطة لكنها قوية: تستمع لصوت إنجليزي أصلي وتكرره فوراً بصوت عالٍ — كظل يتبع المتحدث بتأخير 1-2 ثانية. تُظهر الأبحاث تحسناً كبيراً في دقة النطق والتنغيم والإيقاع وربط الأصوات والاستماع والطلاقة.

تقنية الشادوينغ: اقرأ الدليل الكامل خطوة بخطوة →