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Yr 12 Biology: Research Assessment Part B – Blood By Peter Rowlands.

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1 Yr 12 Biology: Research Assessment Part B – Blood By Peter Rowlands

2 The composition of blood Blood is composed for the most part of four main substances: -Red Blood Cells (RBC’s) -White Blood Cells (WBC’s) -Plasma -Platelets

3 Parts of donated blood which are extracted, and how they are separated: -Red Blood cells: Red blood cells can be obtained from whole blood by means of centrifugation: In this case, the whole blood sample undergoes centrifugation until the heavier red blood cells are separated from the whole blood. Complete separation and extraction of the red blood cells from the blood cells can be achieved in two different ways; -The Centrifuged blood can be placed in a bag, which allows the red blood cells to drain through a port in the bottom of the bag. Following this method, some red blood cells may be left over, but mainly all that remains in the bag will be the buffy coat (coagulation) of white blood cells and platelets, and plasma. Once separated and extracted from the blood, the red blood cells can be used to boost the oxygen carrying capability of patients with anemia or following severe blood loss.

4 -In the second method, the blood is centrifuged less hard, leaving the platelets suspended in the plasma. The Platelet rich plasma is then squeezed from the top to leave the red blood cells, a buffy coat of white blood cells and a smaller amount of platelet-rich plasma. This mixture is then further concentrated of red blood cells. Following this, a nutrient rich additive is added to the sample, making it less viscous for emergency administration.

5 -Plasma: -Following donation, the plasma is still rich with platelets. To counter this, the plasma is centrifuged hard, separating and removing the heavy platelets from the sample. With the intention of combating infection and boosting the effectiveness of donated and centrifuged plasma, the sample is then frozen at – 18ºC for one year, or –65ºC or seven years. Once thawed, it can be kept at 1–6 ºC for 5 days. Used to increase the volume of blood following severe blood loss.

6 -Platelets: The aforementioned Platelet-rich plasma is centrifuged, isolating, separating and removing the platelets from the buffy coat. There is some evidence that may suggest that this method may not be very effective. The argument states that the process of centrifuging the platelet-rich plasma may activate some of the platelets, rendering them useless for medical purposes. A different way in which Platelets may be separated from the blood is by methods of aphaeresis. They are often donated to patients suffering from Leukemia or severe blood loss.

7 - White Blood cells: White blood cells are separated and removed from the blood through the method of leukoreduction. The main reason this is done is to reduce the risk of complications with the blood donations and transfusions: White blood cells have been recognized to cause complications in transfusion such as Immunologically mediated effects, Infectious disease transmission and Reperfusion injury. Leukoreduction involves the filtration and removal of red blood cells and platelets from the blood sample. Used to boost the immune system. E.g. Following a severe infection.

8 Artificial blood: Artificial blood carries oxygen throughout the body in situations where someone’s red blood cells are not able to do this competently on their own. Because of this trait, it is known as oxygen therapeutic. Until recently, all attempts to create an artificial blood substance have failed. There have been large amounts of research done in this area. Recently, scientists have created several effective blood substitutes which have been classed in two categories: Perflurocarbons (PFC’s), and Haemoglobin-Based Oxygen Carriers (HBOC’s). These are much smaller than red blood cells and both work through the process of passive diffusion: moving from the lungs to the blood, where it diffuses into the body tissue surrounding the capillaries. Many of these such substances are nearing the end of testing phases and should hopefully be available to hospitals in the near future. Some Blood substitutes are already in use in areas of South Africa, where they are helping to control the mortality rate of HIV.

9 The need for Artificial Blood: Artificial Blood is in high demand, and for good reason. It can be sterilized in order to kill of bacteria and infections, can be made compatible with up to 98% of the population, can be stored for longer periods of time, and can be used in great quantities in situations where blood is needed, e.g. artificial blood could revolutionise treatment in war zones, ambulances, and disaster areas.

10 Bibliography - 1 Internet: "Blood Basics." Blood Basics. American Society of Hematology, n.d. Web. 20 Nov "Blood Components." Australian Red Cross Blood Service. Australian Red Cross Blood Service, n.d. Web. 20 Nov Collins, Nick, Science Correspondent. "Artificial Blood Could Be Used within next Decade."Http://www.telegraph.co.uk. N.p., 27 Oct Web. 20 Nov Wilson, Tracy V. "How Artificial Blood Works." HowStuffWorks. N.p., n.d. Web. 20 Nov

11 Bibliography - 2 Books/Scientific Journals: Graham D. Sher, Vice-President, Medical, Research and Clinical Management Canadian Blood Services. "LEUKOREDUCTION OF THE BLOOD SUPPLY." (n.d.): n. pag. Web. 20 Nov Hess, John R. "Conventional Blood Banking and Blood Component Storage Regulation: Opportunities for Improvement." Blood Transfus ( ): n. pag. Print. Tortora, Gerard J., and Sandra Reynolds. Grabowski. Principles of Anatomy and Physiology. New York: Wiley, Print.


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