Blood

Blood and your body

What is blood and why is it so important?

Importance of blood

Blood has three main functions: transport, protection and regulation. Approximately 8% of an adult's body weight is made up of blood. Females have around 4-5 litres, while males have around 5-6 litres. Its mean temperature is 38 degrees Celcius and it has a pH of 7.35-7.45, making it slightly basic.

For more information, see Blood Function and Composition.

A, B or O: What is a blood type?

Blood type

The ABO blood groups are made up of 4 types of blood - A, B, AB and O. An individual's ABO blood type is determined by the hereditary presence or absence of the antigens A and B on the surfaces of RBCs. People with type A blood have the antigen A on the surface of their RBCs, while people with type B blood have the B antigen. Individuals with type AB blood have both A and B antigens, whereas people with type O blood have no antigens present.

For more information, see Blood Types (Blood Groups).

What do your blood test results mean?

Blood test results

A full blood count (FBC) is a very common clinical procedure and often the “starting point” for most medical investigations. An FBC not only tests for disorders and abnormalities of the blood but, as blood travels throughout the whole body, it can give an indication of disease present in other organs.

For more information, see Full Blood Count.

Blood donation and transfusion

Video: Artificial blood substitutes

Artificial blood substitutes

Dr Nicholas Wickham explains the importance of blood and blood products. He talks about the advantages of artificial blood substitutes, and the current substitutes available.

Watch a video on Artificial Blood Substitutes.

The importance of blood donation and transfusion

Blood transfusions

Blood is a bodily fluid which carries oxygen, nutrients and wastes around the body via small vessels. Since blood serves such an important function, large losses of blood volume can be fatal. Some people may have conditions which affect certain components of their blood, such as the white blood cells, red blood cells and platelets. A person may require extra blood if they have serious bleeding, haemophilia, cancer or serious anaemia.

For more information, see Blood Transfusion.

Video: Blood donation

There are many gifts that we can give each other in this world. Possibly the most valuable one is the gift of life. We hear a lot about blood donation and at times the Red Cross will call for donors, but what do we really achieve or what happens when we give blood?

Watch a video on Blood Donation.