Blood Analysis Essays - Blood, Anatomy, Medicine, Hematology

Blood Analysis Blood is a fluid substance that circulates in the arteries and veins of the body. Blood is bright red or scarlet when it has been oxygenated in the lungs and passes into the arteries; it becomes bluish red when it has given up its oxygen to nourish the tissues of the body and is returning to the lungs through the veins and the tiny vessels called capillaries. In the lungs, the blood gives up the carbon dioxide wastes it has taken from the tissues, receives a new supply of oxygen, and begins a new cycle. This movement of blood is brought about by the coordinate activity of the heart, lungs, and blood vessels. Blood is composed of a yellowish fluid, called plasma, in which are suspended the millions of cells that constitute about 45 percent by volume of whole blood. It has a characteristic odor and a specific gravity between 1.056 and 1.066. In an average healthy adult, the volume of blood is one-eleventh of the body weight, or between 4.5 and 6 liters (5 and 6 qt). A great portion of the plasma is composed of water, a medium that facilitates the circulation of the many indispensable factors of which blood is composed. A cubic millimeter of human blood contains about 5 million red corpuscles called erythrocytes; 5000 to 10,000 white corpuscles called leukocytes; and 200,000 to 300,000 platelets called thrombocytes. The blood also carries many salts and organic substances in solution. Blood type, in medicine, classification of red blood cells by the presence of specific substances on their surface. Typing of red blood cells is a prerequisite for blood transfusion. In the early part of the 20th century, physicians discovered that blood transfusions often failed because the blood type of the recipient was not compatible with that of the donor. In 1901 the Austrian pathologist Karl Landsteiner classified blood types and discovered that they were transmitted by Mendelian heredity . The four blood types are known as A, B, AB, and O. Blood type A contains red blood cells that have a substance A on their surface. This type of blood also contains an antibody directed against substance B, found on the red cells of persons with blood type B. Type B blood contains the reverse combination. Serum of blood type AB contains neither antibody, but red cells in this type of blood contain both A and B substances. In type O blood, neither substance is present on the red cells, but the individual is capable of forming antibodies directed against red cells containing substance A or B. If blood type A is transfused into a person with B type blood, anti-A antibodies in the recipient will destroy the transfused A red cells. Because O type blood has neither substance on its red cells, it can be given successfully to almost any person. Persons with blood type AB have no antibodies and can receive any of the four types of blood; thus blood types O and AB are called universal donors and universal recipients, respectively. Other hereditary blood-group systems have subsequently been discovered. The hereditary blood constituent called Rh factor is of great importance in obstetrics and blood transfusions because it creates reactions that can threaten the life of newborn infants. Blood types M and N have importance in legal cases involving proof of paternity. A chemist uses liquid chromatography to analyze a complex mixture of substances. The chromatograph utilizes an adsorbtive medium, which when placed in contact with a sample, adsorbs the various constituents of the sample at different rates. In this manner, the components of a mixture are separated. Chromatography has many valuable applications, such as determining the level of pollutants in air, analyzing drugs, and testing blood and urine samples. Gas chromatography separates the volatile constituents of a sample, and liquid/liquid chromatography separates small, neutral molecules in solution. The goal in conducting a separation is to produce a purified or partly purified form of the desired constituent for analytical measurement, or to eliminate other constituents that would interfere with the measurement, or both. Separation is often unnecessary when the method is highly specific, or selective, and responds to the desired constituent while ignoring others. Measuring the pH, or hydrogen ion content, of blood with a glass electrode is an example of a measurement that does not require a separation step. QHP 7694 Head Space Sampler is a machine that equilibrates the sample vials at the desired temperature for the specified time period. A needle then punctures the teflon coated septum at the top