composition of blood

red blood cell

The function of the red blood cell is to carry oxygen from the lungs to the tissues of the body and to carry carbon dioxide back.

To do this, it requires the protein haemoglobin which contains an iron ion.

Each haemoglobin molecule can carry up to four oxygen molecules.

Red blood cells make up between 40- 45% of the blood volume.

white blood cell

There are several types of white blood cells all of which are concerned with protecting the body from infection and cancer.

Different types of white blood cell do this in different ways.

The white blood cells make up about 1% of the volume of the blood.

platlets

Platelets are small fragments of cells. They are also known as thrombocytes.

Their function is to clot blood to prevent loss of blood after a cut.

Plasma

Plasma makes up about 65% of the volume of the blood.

It is the liquid part and is mostly composed of water with dissolved substances such as nutrients, as well as proteins and hormones.