Name: suspensions, sedimentation, and colloids
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 17 s
Channel: JoVE

コロイドと懸濁液は、2つ以上の物理的に混合された成分の不均一な混合物です。
コロイドでは、溶質粒子のサイズは1〜1000ナノメートルの範囲であり、個別には見えないほど小さいです。ただし、これらの溶質粒子は光を散乱させる可能性があり、コロイドを半透明または不透明に見せます。それらは無期限に解決策に残り、落ち着きません。
生細胞内の半流動物質であるサイトゾルは、多数のタンパク質と代謝物が分散しているため、コロイドです。
対照的に、懸濁液には、通常10000ナノメートルを超える大きな粒子が含まれており、多くの場合、肉眼で見ることができます。
乱されないままにしておくと、これらの粒子は堆積物として沈殿します。
血液は懸濁液の一例です。採取したばかりの血液をしばらく放置すると、赤血球が容器の底に沈殿します。血漿と呼ばれる上部の液体部分は、小さな溶質と大きな血漿タンパク質を含むコロイドの溶液です。

コロイドと懸濁液

遊ぶ子供たちはしばしば、泥と水や小麦粉と水、絵の具として知られる水中の固体顔料の懸濁液など、懸濁液と呼ばれる混合物を作ります。これらの懸濁液は、肉眼や拡大鏡で見ることができる比較的大きな粒子から成る非均質な混合物です。それらは曇っており、混合後には懸濁粒子が沈殿します。懸濁液中の懸濁粒子は、混合後にしばらくすると沈殿します。懸濁物質が混合物から粒子が分離することを沈降と呼びます。沈降速度を測定する血液検査では、試験管中の赤血球が血液（プラズマとも呼ばれます）の水分部分からどれくらいの速さで沈殿するかが測定されます。健康な体内では、血球の迅速な沈降は通常起こりません。しかし、特定の病気の要素によって血球が凝集し、これらの重い血球の塊が通常の血球よりも速く試験管の底に沈みます。 コロイドと呼ばれる別の混合物のクラス（またはコロイド分散体）は、懸濁液と溶液の性質の中間を示します。コロイド中の粒子は、ほとんどの単純な分子よりも大きいですが、コロイド粒子は立っている間に沈殿しません。コロイド混合物は、光を散乱するほどの十分な大きさの粒子を含んでいるため、タイントール現象と呼ばれる現象によって曇りや不透明に見えます。雲もまたコロイド混合物です。それらは分子よりもはるかに大きい水滴でできていますが、沈殿しないほど小さいです。一部のコロイドはソル-ゲル変換の特性を持ち、流体から固体（ゲル）状態に可逆的に変化することができます。たとえば、ゼラチン製品は冷蔵するとゲル状に固まり、加熱すると再び液化できます。細胞の液体である細胞質のソル-ゲル特性は、細胞分裂や細胞形状の変化など、多くの細胞活動にとって重要です。比較的少量含まれるコロイド溶液の粒子成分は、分散相と呼ばれます。粒子が分散する物質または溶液全体は、分散媒と呼ばれます。この文章は「<a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-4-inorganic-compounds-essential-to-human-functioning">Openstax, Anatomy and Physiology 2e, Section 2.4: Inorganic Compounds Essential to Human Functioning</a> and <a href="https://openstax.org/books/chemistry-2e/pages/11-5-colloids">Openstax, Chemistry 2e, Section 11.5: Colloids</a>.

遊んでいる子供たちは、泥と水、小麦粉と水の混合物、またはテンペラとして知られる水中の固体顔料の懸濁液などの懸濁液を作ることがよくあります...

Education

JoVE Core

Anatomy and Physiology

解剖生理学

Unit 1

ユニット1

Fundamentals of Chemistry

化学の基礎

KEY TERMS AND CONCEPTS

主要用語と概念

Colloids and Suspensions

suspensions, sedimentation, and colloids

Suspensions and colloids are two common kinds of mixtures seen in everyday life. Mud and water, flour and water, and tempera paint are suspensions. These mixtures are heterogeneous, which means their particles are not spread out evenly. The particles are relatively large and can be seen with the naked eye or a magnifying glass.

Suspension particles make mixtures cloudy, and they settle out after mixing. The settling of particles in a suspension is called sedimentation. A blood test can measure the rate of sedimentation by showing how fast red blood cells settle out of plasma, the watery part of blood, in a test tube over time. Rapid sedimentation is not usual in a healthy body, but some diseases can cause blood cells to clump together and sink faster than normal cells.

Colloids, also called colloidal dispersions, sit between suspensions and solutions. Their particles are larger than most simple molecules, but they are small enough that they do not settle out when left standing. Colloidal particles are still large enough to scatter light. This is known as the Tyndall effect, and it makes colloids look cloudy or opaque, like a beam from a searchlight.

Clouds are another example of a colloid. They contain water droplets that are bigger than molecules, but still small enough to stay suspended in the air. Some colloids can also change from a fluid sol to a solid gel and back again. Gelatin is one example. It forms a gel when chilled and can become liquid again when heated. The sol-gel behavior of cytosol, the fluid inside living cells, is important for cell division and for changes in cell shape.

In a colloid, the dispersed phase is the particulate part present in smaller amount. The dispersion medium is the substance that carries the particles throughout the mixture. These terms help describe how colloids are organized and why they behave differently from suspensions and solutions.

Suspensions, Sedimentation, and Colloids

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electron behavior

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colloids and suspensions

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key terms and concepts

Learn how suspensions settle, how sedimentation works, and why colloids stay cloudy without settling. Explore real examples like blood, clouds, and gelatin.

Suspensions, Sedimentation, and Colloids | JoVE K12

anatomy and physiology

JoVE Core 解剖学と生理学では、人体の解剖学的および生理学的な詳細を、包括的で明確で魅力的なビデオ アニメーションで紹介します。このレッスン集は、人体の構造、コンポーネント、機能、要件に焦点を当てています。この知識を実際の医療および研究現場で応用することを実証する科学者による実際のビデオによって補完されています。

Suspensions, Sedimentation, and Colloids

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