Transport in the Blood B3 2.3 p.238

Outcomes Most students should be able to: describe the composition of the blood describe the structure of red blood cells and their role in the blood describe how oxygen is transported from the lungs to the other body organs by haemoglobin describe the structure and functions of the white blood cells and the platelets describe the functions of the blood plasma in the transport of substances around the body. Some students should also be able to: explain how red blood cells are adapted to carry out their function describe the reversible reaction between haemoglobin and oxygen.

Workbook homework p. 112

Which type of blood vessels?

What is blood made up of?

Name of part of blood Brief description / diagramFunction(s)

Blood Plasma The liquid part of our blood is called plasma. It transports red blood cells, white blood cells and platelets. Blood plasma is a yellow liquid which transports all blood cells and other substances around the body. Carbon dioxide produced as a by- product of aerobic respiration is carried in the plasma back to the lungs. It is the red blood cells which give blood its red colour.

Red Blood Cells Red blood cells pick up oxygen from your lungs and carry it to where it is needed for aerobic respiration. DID YOU KNOW? One red blood cell contains about 250 million molecules of haemoglobin which allow it to carry 1000 million molecules of oxygen There are more red blood cells than any other type of cell in your body – about 5 million in each cubic millimetre of your blood

A red blood cell has several features that help it do its job: Biconcave disc-shaped, with a dent on each side, creates a large surface area for gas exchange. A large surface area compared to volume, so oxygen is always close to the surface. Short diffusion distance How are red blood cells adapted to carry oxygen? It contains haemoglobin, a special pigment that combines with oxygen. It has no nucleus, so there is more space for haemoglobin and so more oxygen.

Gases moving in and out of the blood

The reversible reaction between oxygen and haemoglobin

The reversible reaction between oxygen and haemoglobin WHAT ORDER SHOULD IT BE? 1 Circulatory system transports the oxygen bound to the haemoglobin 2 Tissues respire using oxygen up 3 Oxygen diffuses from high to low concentration into the blood, and red blood cells In the lungs 4 Oxygen leaves the haemoglobin and diffuses from high to low concentration into the tissues 5 Haemoglobin binds oxygen in the blood

The reversible reaction between oxygen and haemoglobin Oxygen diffuses from high to low concentration into the blood, and red blood cells In the lungs Haemoglobin binds oxygen in the blood Circulatory system transports the oxygen bound to the haemoglobin Oxygen leaves the haemoglobin and diffuses from high to low concentration into the tissues Tissues respire using oxygen up

White Blood Cells Much bigger than RBCs and there are fewer of them. Have a nucleus and form part of the body’s self-defence system against harmful microorganisms. Some WBCs form antibodies against microorganisms. Other digest invading bacteria and viruses (phagocytosis).

Blood clotting (Platelets) At the site of a cut or wound the blood will clot. This prevents further blood loss, reduces the risk of pathogens entering and forms a framework for repairing the damaged tissue. Platelets will rapidly stick to a damaged area, releasing chemicals that start a series of complex reactions. This results in a network of protein threads that trap blood cells and more platelets to form a jelly-like clot. The clot dries and hardens to form a scab which protects the skin and stops bacteria getting into your body

Which component?

Blood under the microscope Try and focus in high power to see the cells

In your books – match up the correct words and statements about blood Component Function Plasma These cells form part of the body’s defence system against microorganisms. There are many different types. Red blood cells This liquid transports carbon dioxide from the organs to the lungs, soluble products of digestion from the small intestine to other organs, and urea from the liver to the kidneys. White blood cells These are small fragments of cells. They help blood to clot at the site of a wound. Platelets These cells transport oxygen from the lungs to the organs. They have no nucleus. They are packed with a red pigment called haemoglobin.

Can I be a blood donor? Blood donors must be over 17 years old and are always needed In small groups of 3 or 4, think of reasons why a person should not donate blood After 5 minutes discussion, produce a list of reasons as a class

Blood transfusions Blood is regularly donated by thousands of people around the UK. The national blood service obtains, transports and tests blood from donors before it is used. A blood transfusion involves taking blood from one person and giving it to another. Blood transfusions are used to replace blood lost in accidents, after surgery and to treat blood conditions. Hospitals will store a large amount of donated blood.

Real blood Blood is vital to life – if you lose too much you can die. Patients can be given blood plasma or saline to restore blood volume, but using real blood for transfusions presents several problems – can you think of any?

Draw a table like the one below to input your notes during the next few slides TopicBrief descriptionAdvantagesDisadvantages Real Blood Artificial Blood Haemoglobin- based products Perfluorocarbons (PFC’s) Artificial mechanical heart

Disadvantages of using real blood It has to be kept refrigerated It has a shelf life of only 42 days People have different blood groups that need to be matched Real blood may be contaminated by viruses e.g. HIV There is often a shortage of blood donors Some people cannot accept blood transfusions for religious reasons

Artificial blood Contains no cells. 2 main types are on trial:

Advantages of artificial blood (currently being trialled in Europe) Shelf life of a year or more It does not need refrigeration It can be sterilised so does not carry disease It is safe regardless of blood type as does not contain any cells But it can’t do all the work of real blood

Haemoglobin based products Based on haemoglobin taken from human or animal blood Can be made synthetically or by genetic engineering This haemoglobin carries even more oxygen than normal blood Disadvantage: it is broken down quickly and only lasts in the body for hours

Perfluorocarbons (PFCs) These are very non- reactive chemicals that can carry oxygen around your body Oxygen dissolves very readily in PFCs Disadvantage: PFCs don’t dissolve in water, so getting them into the blood is difficult

Use the data in the graph on p.240 and the next slide to help you explain why there is so much interest in developing artificial blood products Activity 1

Artificial Hearts Scientists are also trying to develop artificial hearts, since there are not nearly enough donors and it is difficult to find a donor with the right tissue type In 2010, a 43 year old American was the first person to leave hospital with a completely artificial heart He carried it in a back-pack!

Artificial hearts work by pumping deoxygenated blood from the body to the lungs. The device then pumps oxygenated blood through the body. The newly approved device, called AbioCor, made by Massachusetts-based Abiomed, uses an implanted hydraulic pumping system to simulate a natural heart beat. But an alternative design, conceived by O.H. "Bud" Frazier, a prominent heart surgeon and pioneer in the development of cardiac devices at the Texas Heart Institute in Houston, pumps blood through the body continuously, rather than with the periodic beat of the normal heart. Extension: How do they work?

Problems with artificial hearts? Expense Problems with blood clotting Size

Questions Answer q.1 and 2 p.240 Workbook p.113

Plenary: How science works – which one should I have? Scientists are working on developing an artificial heart that can be fitted into patients Read the information about this and think about the ethical issues involved Complete the task questions

Homework Choose from: A. Make a poster encouraging people to give blood. Include information about the need for blood and the advantages and limitations of the artificial bloods developed so far (the NHS Blood and Transport website is useful) B. Make a poster or presentation about the history of heart transplants and the benefits of artificial hearts

Extension - ABO blood grouping Cells contain markers on their surface, called antigens. Red blood cells can contain two types of antigens called antigen A and antigen B. These form the basis of a type of blood grouping called the ABO blood system. blood group O – cells do not contain antigens A and B Blood groups can be classified by the presence or absence of these antigens: blood group A – cells contain antigen A only blood group B – cells contain antigen B only blood group AB – cells contain antigens A and B

Who can receive what type of blood? The immune system will contain antibodies against the antigens that are not present in the blood. For example group A blood will contain antibodies against antigen B. If a recipient's anti-B antibodies come in contact with blood cells containing antigen B this will cause clotting. This affects blood donation, e.g. a person with group A blood can only receive blood group A or O, as these don’t contain B antigens. Blood groupAntigensAntibodies Can receive O A B AB None A B A and B anti-A, anti-B anti-B anti-A None O A and O B and O All groups

Extension - Donating ABO groups