← 🫀 Human body · usually met in Std 7-12
A transport fluid: red cells carry oxygen, white cells fight infection, platelets stop leaks, and plasma carries everything else.
Red blood cells are packed with haemoglobin, an iron-bearing protein that grabs oxygen where there is plenty and releases it where there is little. They have no nucleus in humans, which leaves more room for cargo. White blood cells are the immune system's workforce. Platelets are fragments that clump at a wound and start the chain of reactions that forms a clot. Plasma, the straw-coloured liquid, carries nutrients, hormones, waste and heat.
Blood groups matter because the immune system attacks cells it does not recognise. The ABO system and the Rh factor together decide who can safely receive blood from whom, and getting it wrong is dangerous. Donated blood is tested and matched for exactly this reason.
Want to see it moving? Search YouTube for “Blood” ↗ — we send you to the search rather than to one video, because a link to one video eventually rots.
This entry was written for Star Student in our own words — it is a summary, not a source. Here is where the people who actually hold these facts keep them. Go and check.
Your own textbook ↗Balbharati publishes the textbooks free to read online. Your chapter is the thing to check first — an encyclopedia is a summary, and the syllabus is the syllabus. World Health Organization ↗Health facts stated carefully, and updated when the evidence changes.Last gone through: 1 October 2026 · How these entries are written
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