Blood
Introduced| English | Meaning |
|---|---|
| red blood cells/red blʌd selz/ | Blood cells specialised to carry oxygen using haemoglobin. |
| haemoglobin/ˌhiːməˈɡləʊbɪn/ | The iron-containing protein in red blood cells that binds and transports oxygen. |
| biconcave/baɪˈkɒŋkeɪv/ | biconcave |
| platelets/ˈpleɪtlɪts/ | platelets |
| plasma/ˈplæzmə/ | The liquid component of blood in which cells, proteins and other dissolved substances are carried. |
| white blood cells/waɪt blʌd selz/ | white blood cells |
| clot/klɒt/ | A solid mass of blood formed to seal a wound. |
More than a red liquid
- Blood looks like a simple red liquid, but it's a mixture of cells and fluid doing many jobs at once.
- It has four main parts.
Blood component lab
Classify blood components by the job they do.
Red blood cells carry oxygen using:
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Haemoglobin binds oxygen.
Red blood cells have a large nucleus to control haemoglobin production.
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False. Mature red blood cells have no nucleus, leaving more room for haemoglobin; their biconcave shape also suits oxygen transport.
Red blood cells 红细胞
- Red blood cells carry oxygen, using the red pigment haemoglobin 血红蛋白.
- They have no nucleus and a biconcave 双凹的 shape — more room and surface area for oxygen.

Blood is red cells, white cells and platelets 血小板 carried in liquid plasma 血浆
White blood cells:
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White blood cells defend against pathogens.
Platelets help to:
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Platelets are needed for clotting.
White blood cells 白细胞 and platelets
- White blood cells fight pathogens (some engulf them, some make antibodies).
- Platelets are cell fragments that help the blood to clot 凝血 at a wound.
The liquid part of blood that carries cells and nutrients is ______.
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Plasma carries cells, nutrients, hormones, waste and heat.
Plasma
- Plasma is the pale yellow liquid that carries everything: blood cells, nutrients, hormones, waste and heat.
Worked example. A red blood cell's lack of a nucleus leaves more space for haemoglobin, and its biconcave disc shape gives a large surface area — both adaptations for carrying as much oxygen as possible.
You've got it
- red blood cells carry oxygen (haemoglobin; no nucleus; biconcave)
- white blood cells fight pathogens; platelets help clotting
- plasma is the liquid carrying cells, nutrients, hormones, waste and heat
Write from a red cell with no nucleus
- A blood cell is biconcave and carries oxygen.
- Small fragments in the same sample help the blood clot.
What is each part, and what does plasma carry besides cells?
Shape and the missing nucleus fit the oxygen job.
Which part of the blood helps clotting?
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Platelets start the clot.