Understanding the Components of Blood: Red Cells, White Cells & Platelets

The solid part of blood consists of:

* Red blood cells (erythrocytes): These are small, disk-shaped cells that contain the oxygen-carrying protein haemoglobin. Red blood cells are produced in the bone marrow and have a lifespan of around 120 days.

* White blood cells (leukocytes): These are larger than red blood cells and play a role in the body's immune system. White blood cells are produced in the bone marrow and lymph nodes and have a lifespan of a few days to several years.

* Platelets (thrombocytes): These are small, colourless cells that play a role in blood clotting. Platelets are produced in the bone marrow and have a lifespan of around 10 days.