Lesson starter Once a protein has denatured, it cannot return to its original shape. Explain why. Haemoglobin is a protein found in the blood. Name two other proteins found in blood. The bonds holding it in its tertiary structure have broken, and the molecule becomes tangled up with other molecules. This stops it reforming into its original shape Albumin, fibrinogen, prothrombin

Storing blood Learning objectives outline the types of blood products stored: whole blood, leuco-depleted blood, packed red cells, platelets, clotting factors and plasma; outline the use of blood products: whole blood, leuco-depleted blood, packed red cells, platelets, clotting factors and plasma; outline how blood products are screened and treated to prevent the transmission of HIV and hepatitis C (HSW6b, 7b, 7c).

Types of blood products Donor blood is rarely used directly for transfusion these days. Instead, it is processed into different blood products used for different purposes. Examples you need to know are: Whole blood Leuco-depleted blood Packed red cells Platelets Clotting factors plasma

Whole blood Contains everything that is in blood Erythrocytes (red blood cells) Leucocytes (white blood cells) Platelets Plasma This product was more commonly used in the past, but is rarely used now, except for severe blood loss.

Leuco-depleted blood This is blood that has had as many of the leucocytes removed as possible. This is important for patients who receive repeated transfusions. White blood cells are more likely to provoke the patient’s immune system into making antibodies. This can cause problems with future transfusions

Packed red cells The red blood cells are separated from the rest of the blood and stored. When needed, the cells are diluted with a salt and sugar solution. There will be no white blood cells present in the final solution. This is used in many kinds of transfusion, especially for people with anaemia, or to replace lost red blood cells after surgery or childbirth

Platelets Platelets are particularly useful for patients with bone marrow failure They are also used following transplant and chemotherapy treatments, and for patients with leukaemia

Clotting factors Plasma from blood donations can be processed to provide clotting factors. There are many soluble proteins in plasma that help the blood to clot. Some people many have a condition in which one of these blood clotting factors is missing. This means that their blood is slow to clot. For example, a person with classical haemophilia does not have factor VIII in their blood. These people can be treated with transfusions of factor VIII

Plasma Plasma is blood from which all the blood cells have been removed Fresh frozen plasma is used during cardiac surgery, to reverse any anti-coagulent treatment and when a woman has lost blood during childbirth It is also used to replace clotting factors after major transfusions or when clotting factors are not being produced in sufficient quantities, such as liver disease

Screening blood When people volunteer for blood donation, it is vital that their health is checked A small sample of blood is taken for testing when blood is donated. This is normally done by a machine that checks for the following viral infections: HIV Hepatitis C If exposed to a virus, antibodies will be found in the blood. During testing, antigens are added to the blood sample to see if any antibodies will combine with them Blood is also tested to find out the blood group of the donor. This is important so that the correct blood is given to a patient

Blood group distribution

Exam questions - plenary

Exam questions - plenary