Biology - Blood Components and Blabla

Biology – Problem Solving and Communication
Question 1

Question 2
There are many products of whole blood which can be extracted (via the process of centrifugation) for further use for patients who require specific blood products. These components include red blood cells, plasma and platelets where these products are then used for many purposes in the medical field.
Red blood cells (RBC), which can be turned into a concentrate with 2 times more red blood cells than whole blood, is critical in treating patients with anaemia (a deficiency in the quantity or efficiency of red blood cells) by increasing the oxygen-carrying capabilities within the body of a patient. and are essential in replacing red blood cells that have been lost due to accidents, surgical procedures or from illnesses such as leukaemia. However there are limitations for the use of these packed RBCs, as the oxygen delivery to tissues are restricted. It is also indicated that patients who received these transfusions had a higher rate of infections and death compared to those who didn’t receive RBC concentrate.
Plasma is a protein-salt solution which constitutes as 55% of the volume of blood. This liquid is where platelets, red and white blood cells are located. Plasma can be dried out into a powder or frozen which contains clotting factors to treat patients with disorders such as haemophilia (specific clotting factors are missing in the blood, which then results in excessive bleeding) and sepsis (severe illness where the bloodstream is overwhelmed by bacteria). Frozen plasma contains all necessary clotting factors and are free of red blood cells, white blood cells and platelets. It can serve as a medium of exchange for vital minerals (such as sodium and potassium) for patients who require clotting effects immediately (e.g. major blood transfusions) which in return, aids the body in maintaining a proper balance for optimum cell function. The allowable volume of plasma being extracted from a donor is restricted to approximately only 10-15 litres a year due to the negative effects on albumin (water soluble protein molecules found within blood) levels. Extraction of plasma can also lead to high blood pressure, so the amount taken from a donor must be carefully monitored.
Platelets are small fragments of cells made from the bone marrow which is usually congregated in large numbers where it is essential for the coagulation of blood. Platelets are taken from the donor through the process of aspheresis, where the blood is drawn out and placed centrifuged to separate it from the plasma and other components of blood. The result is concentrated platelets where there is six times as much platelets compared to the concentration within whole blood. This platelet concentrate are then transferred to patients with diseases where the platelets do not function properly within the blood of the patient. However, there are also disadvantages with platelet transfusions due to the significant risk of immunologic disorders and bacteria within the platelets which can be transferred through to the patient. Question 3
The need for blood is universal; hence blood is in high demand. There is not enough blood donations which can keep up with the demand, therefore blood substitutes are being made to further reduce the overwhelming need for hospitals around the world to gather blood. The HIV crisis during the 1980s triggered the further development of artificial blood to prevent the spread of HIV from donor blood supplies.
Blood has a primary function of the removal of carbon dioxide and transportation of oxygen to every cell, tissue and organ of the body. This is the basic idea of what a blood substitute is like; it imitates the oxygen-carrying capabilities of red blood cells. However artificial blood is not a supplementary for real blood and so it only acts as a temporary supply of blood for the bone marrow to create a sufficient amount of blood cells for the body to function properly.
The most significant blood substitute is Hemopure, which is a haemoglobin-based blood substitute usually used during acute anaemia where RBCs are incapable of transporting oxygen throughout the body properly. It has been developed to prevent any future HIV crises and other blood-related diseases. The development of Hemopure is through the extraction of blood within cattle which is then purified to its important components such as haemoglobin. Although this blood substitute was considered a breakthrough in the medical industry, current researches have shown that Hemopure increases the chances of a heart attack due to nitric oxide contained within it. This chemical causes vasoconstriction where the patients are 2.7 times more likely to have a heart attack and an increased chance of death rate. This then leads into a research of why blood substitutes can cause heart attacks in patients.
Shelf life is also a major factor of artificial blood; henceforth research has lead to the production of bovine haemoglobin, a blood substitute which has a three year shelf life at room temperature. Other advantages of this substitute are its effect in curing hemorrhagic shock, protecting the kidneys and preventing any damage to the cardiovascular system. This substitute is then able to accommodate the increasing demand for blood. The cost of this substitute is not costly so it is able to be used by all types of patients as the haemoglobin is modified from a bovine source.
Another potential route that researchers have explored blood pharming, where RBCs are extracted from umbilical cords to further grow more RBCs. The first step of creating blood cells is to isolate the stem cells from an umbilical cord and then culture the cells using a polymer substrate that expands the stem cells rapidly. These stem cells are then cultured into forming red blood cells where it is filtered and placed into plasma which can then be transferred into the body. The biotechnology firm Arteriocyte plans to expand this approach into remote areas such as war zones where blood substitutes can be readily transferred when required.
PFC’s have been found to be excellent oxygen carriers compared to other types of artificial blood, but this chemical is not a natural product, hence human lungs cannot adapt to the man-made blood efficiently. Other disadvantages include spine-ache and flu symptoms.
Artificial blood is a very new in research; hence there are still many major breakthroughs that have yet to be found. Blood substitutes like Hemopure, PFCs and blood pharming are still being perfected therefore the need for blood is still high within the medical industry. As technology advances, the possibility of blood substitutes permanently replacing natural blood increases. Question 4
Aldosterone is a mineralocorticoid, a chemical which controls the balance of salts (sodium and potassium ions) and water within the body that is produced within the adrenal glands located above the kidneys. If the salt concentrations of blood are high, this then leads to an increase in blood volume and blood pressure as the water is retained within the blood. As a result, the secretion of aldosterone is then reduced where less water and salts are absorbed from the nephron tubules (a part of the kidney), where high salt and water concentrations are lost in urine. Aldosterone can also be released in higher concentrations from the adrenal glands if the body requires more salt concentrations within the body, where water levels drop. The nephron tubules then reabsorb the sodium ions to maintain a balance in salt and water concentrations within the body.
The secretion of aldosterone is a negative feedback system where the hypothalamus detects low levels of aldosterone within the body which in turn stimulates the pituary gland to send messages to the adrenal cortex to produce the hormone. Low blood volumes and blood pressure can result if the adrenal glands cannot secrete aldosterone. This can then lead to Addison’s disease due to the incorrect sodium levels within the body which is lethal, as it causes electrolyte imbalances, high blood pressure, cardiac failure and leads to higher acidity within the blood which can denature the function of enzymes.
To be able to treat or prevent this disease, a hormone replacement therapy is required to maintain the balance of salts and water inside the body. Fludrocortisone acetate (or Florinef) is a synthetic steroid which imitates the actions of aldosterone as a mineralocorticoid. This steroid comes in the form of a tablet which is taken once or twice a day, depending on the patient, where it is consumed to increase their salt intake to prevent low blood pressure and electrolyte imbalances. However if their disease reaches a life threatening point (low blood pressure, low blood glucose and high concentrations of potassium ions), intravenous injections of Florinef and large volumes of saline solution with dextrose (a type of sugar) is transferred into the bloodstream of the patient. This improves their condition rapidly by stabilising the concentrations of salts and fluids within the body.

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