HealthInfo Canterbury

What blood is made of

Ngā kiko o te toto

Your blood is a mixture of blood cells and a liquid called plasma.

Blood cells

Your blood cells are made in your bone marrow. You have three main types of blood cells:

Red blood cells (erythrocytes)

Red blood cells are what make your blood red. They contain a substance called haemoglobin, which carries oxygen around your body. You need iron, vitamin B12 and folic acid for these red blood cells to work properly. If you're low in red blood cells you have what's called anaemia.

White blood cells (lymphocytes)

White blood cells are part of your immune system. They help you fight infections. Infections are the most common cause of high white blood cells.

Platelets (thrombocytes)

Platelets are tiny cell fragments which, (with clotting factor proteins) help your blood clot if you get cut.

Plasma

Plasma is a yellow liquid that contains many chemicals and proteins, which all do different things. They include clotting proteins, hormones, enzymes, antibodies, nutrients, sugars and salts.

  HealthInfo recommends the following pages

• Leukaemia & Blood Cancer New Zealand – Blood basics

  This detailed page can give you a deeper understanding about bone marrow and blood cells.

Written by HealthInfo clinical advisers. Last reviewed February 2023.

Sources

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Review key: HIBBV-38552