BLOOD -
Noun: Blood is essential for life. Blood carries oxygen, nutrients, hormones and chemicals to each of the sixty billion cells throughout the body. It plays an essential part in protecting the body from infection. Blood also helps the body remove waste and toxins. There are close to 30 trillion blood cells in an adult. Each cubic millimetre of blood contains from 4 1/2 to 5 1/2 million red blood cells and an average total of 7,500 white blood cells.

All types of blood cells are produced by the bone marrow . The bone marrow is the soft, spongy tissue found in the centre of the large bones in the body. There are four main components of blood: red blood cells, white blood cells, platelets, and liquid plasma . Since red and white blood cells are continually being destroyed, they body must continue to produce new ones in the bone marrow. About 2 1/2 million new red blood cells are created every second.

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