Q1.
Do you know your blood group? Find out!
Answer
Your blood group is decided by which marker proteins sit on the surface of your red blood cells. In the common ABO and Rh system there are eight groups: A+, A−, B+, B−, AB+, AB−, O+ and O−.
How to find out: a blood group test needs only a drop or two of blood. It is done free at almost every blood donation camp, and at any hospital or pathology laboratory. Some school health check-ups also record it. Write it down and keep it in your school diary — in an emergency it saves valuable minutes.
Why it matters, and how this chapter connects to it: If a patient is given blood of the wrong group, the body treats the incoming cells as foreign and clumps them together, blocking blood vessels. So every donated unit is tested and its group identified before use. It is then separated by centrifugation into plasma, platelets, white cells and red cells (Fig. 5.22) — the same technique you met for muddy water — because one donation can then treat several different patients, each getting only the component they need. The components are stored in blood banks and supplied on demand.
Did you know? The body replaces donated blood naturally within a few weeks, which is why regular donation is safe for a healthy adult. In Chapter 3, Tissues in Action, you learnt that blood connects the different parts of the body by transporting nutrients, gases and hormones — a donation quite literally passes that service on to someone else.