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What is blood? Who needs blood? What are the types of blood and who has them? How much blood does a human body have? How does the body make blood? What is whole blood? What are red blood cells? How are red blood cells used? What is plasma? How is plasma used? What are platelets? How are platelets used? What are white blood cells? How are white blood cells used? What is the complete blood count test (CBC)? How is the complete blood count test (CBC) done? What are the components of the complete blood count (CBC)? What are values for a complete blood count (CBC)? What are the functions of the cells in a complete blood count (CBC)? What is the complete blood count (CBC) used for? Multiple Choice QUestions |
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What is blood? Blood is a living tissue that circulates through the heart, arteries, veins and organs carrying nourishment, electrolytes, hormones, vitamins, antibodies, heat and oxygen to the body’s tissues. Who needs blood? The need for blood is great. Blood transfusions often are needed for trauma victims — due to accidents and burns — heart surgery, organ transplants, and patients receiving treatment for leukemia, cancer or other diseases, such as sickle cell disease and thalassemia. An aging population and advances in medical treatments and procedures requiring blood transfusions also continue to increase the demand for blood. What are the types of blood and who has them? Blood types by percentage of population are as follows: * O positive, 37 percent * O negative, 7 percent * A positive, 36 percent * A negative, 6 percent * B positive, 8 percent * B negative, 2 percent * AB positive, 3 percent * AB negative, 1 percent In an emergency, anyone can receive O negative blood, and those with O negative blood are known as “universal donors.” How much blood does a human body have? An average size female has about nine pints of blood, while an average size male has about 12 pints of blood. How does the body make blood? Red cells, platelets and white cells are made in the bone marrow. Coagulation proteins (clotting factors) are made in the liver and water comes from the body’s general fluid content. What is whole blood? Whole blood is just as it sounds – it is blood with all of its components intact. Whole blood is comprised of red blood cells, white blood cells and platelets suspended in a proteinaceous fluid called plasma. These parts can be separated from whole blood in order to provide patients with superior treatment by giving them the specific elements they need. Whole blood donations can be made every eight weeks (56 days). What are red blood cells? Red blood cells are perhaps the most recognizable component of whole blood. Red blood cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body and gives blood its red color. The percentage of blood volume composed of red blood cells is called the hematocrit. The average hematocrit in an adult male is 47 percent. There are about one billion red blood cells in two to three drops of blood, and, for every 600 red blood cells, there are about 40 platelets and one white cell. Manufactured in the bone marrow, red blood cells are continuously being produced and broken down. They live for approximately 120 days in the circulatory system and are eventually removed by the spleen. Red blood cells are prepared from whole blood by removing the plasma, or the liquid portion of the blood, and can raise the patient’s hematocrit and hemoglobin levels while minimizing an increase in blood volume. How are red blood cells used? Patients who benefit most from transfusions of red blood cells include those with chronic anemia resulting from disorders such as kidney failure, malignancies, or gastrointestinal bleeding and those with acute blood loss resulting from trauma or surgery. Since red blood cells have reduced amounts of plasma, they are well-suited for treating anemia patients who would not tolerate the increased volume provided by whole blood, such as patients with congestive heart failure or those who are elderly or debilitated. What is plasma? Plasma is the liquid portion of the blood – a protein-salt solution in which red and white blood cells and platelets are suspended. Plasma, which is 90 percent water, constitutes about 55 percent of blood volume. Plasma contains albumin (the chief protein constituent), fibrinogen (responsible, in part, for the clotting of blood), globulins (including antibodies) and other clotting proteins. Plasma serves a variety of functions, from maintaining satisfactory blood pressure and volume to supplying critical proteins for blood clotting and immunity. It also serves as the medium of exchange for vital minerals such as sodium and potassium, thus helping maintain a proper balance in the body, which is critical to cell function. How is plasma used? Plasma is most often used to treat certain bleeding disorders when a clotting factor or multiple factors are deficient and no factor-specific concentrate is available. It can also be used for plasma replacement through a process called plasma exchange. What are platelets? Platelets (or thrombocytes) are very small cellular components of blood that help the clotting process by sticking to the lining of blood vessels (basically, they form scabs). Platelets are made in the bone marrow and survive in the circulatory system for an average of 9-10 days before being removed from the body by the spleen. The platelet is vital to life, because it helps prevent both massive blood loss resulting from trauma and blood vessel leakage that would otherwise occur in the course of normal, day-to-day activity. Units of platelets are prepared by using a centrifuge to separate the platelet-rich plasma from the donated unit of whole blood. The platelet-rich plasma is then centrifuged again to concentrate the platelets further. Platelets may also be obtained from a donor through a process known as automation. In this process, blood is drawn from the donor into an automation instrument, which, using centrifugation, separates the blood into its components, retains the platelets, and returns the remainder of the blood to the donor. The resulting component contains about six times as many platelets as a unit of platelets obtained from whole blood. Platelets are stored at room temperature for up to five days. How are platelets used? Principally patients with different forms of cancer and leukemia. Chemotherapy helps save lives but it destroys healthy platelets at the same time. Without platelet transfusions, these patients could bleed to death. Patients suffering from leukemia and other cancers of the blood are doubly affected. In addition to the effects of chemotherapy, their disease may crowd out or destroy the bone marrow cells that make healthy platelets. Despite advances in medical technology, there is still no substitute for platelets... they must come from dedicated volunteer donors. What are white blood cells? White blood cells are responsible for protecting the body from invasion by foreign substances such as bacteria, fungi and viruses. The majority of white blood cells are produced in the bone marrow, where they outnumber red blood cells by two to one. However, in the blood stream, there are about 600 red blood cells for every white blood cell. There are several types of white blood cells. Granulocytes and macrophages protect against infection by surrounding and destroying invading bacteria and viruses, and lymphocytes aid in the immune defense. Granulocytes can be collected through automation or by centrifugation of whole blood and are transfused within 24 hours after collection. How are white blood cells used? White blood cells are used to fight infections that are unresponsive to antibiotic therapy and to produce interferon. The effectiveness of white blood cell transfusion is still being investigated. How is the complete blood count test (CBC) done? The complete blood count (CBC) test is performed by obtaining a few milliliters (one to two teaspoons) of blood sample directly form the patient. It can be done in many settings including the doctor's office, laboratories, and hospitals. The skin is wiped clean with an alcohol pad, and then a needle is inserted through the area of cleansed skin into to patient's vein (one that can be visualized from the skin.) The blood is then pulled from the needle by a syringe or by a connection to a special vacuumed vial where it is collected. This sample is then taken to the laboratory for analysis. What are the components of the complete blood count (CBC)? The complete blood count, or CBC, lists a number of many important values. Typically, it includes the following: * White blood cell count (WBC or leukocyte count) * WBC differential count * Red blood cell count (RBC or erythrocyte count) * Hematocrit (Hct) * Hemoglobin (Hbg) * Mean corpuscular volume (MCV) * Mean corpuscular hemoglobin (MCH) * Mean corpuscular hemoglobin concentration (MCHC) * Red cell distribution width (RDW) * Platelet count * Mean Platelet Volume (MPV) What are values for a complete blood count (CBC)? The values generally included are the following: * White blood cell count (WBC) is the number of white blood cells in a volume of blood. Normal range varies slightly between laboratories but is generally between 4,300 and 10,800 cells per cubic millimeter (cmm). This can also be referred to as the leukocyte count and can be expressed in international units as 4.3 to 10.8 x 109 cells per liter. * White blood cell (WBC) differential count. White blood count is comprised of several different types that are differentiated, or distinguished, based on their size and shape. The cells in a differential count are granulocytes, lymphocytes, monocytes, eosinophils, and basophils. A machine generated percentage of the different types of white blood cells is called the automated WBC differential. These components can also be counted under the microscope on a glass slide by a trained laboratory technician or a doctor and referred to as the manual WBC differential. * Red cell count (RBC) signifies the number of red blood cells in a volume of blood. Normal range varies slightly between laboratories but is generally between 4.2 to 5.9 million cells/cmm. This can also be referred to as the erythrocyte count and can be expressed in international units as 4.2 to 5.9 x 1012 cells per liter. Red blood cells are the most common cell type in blood and people have millions of them in their blood circulation. They are smaller than white blood cells, but larger than platelets. * Hemoglobin (Hb). This is the amount of hemoglobin in a volume of blood. Hemoglobin is the protein molecule within red blood cells that carries oxygen and gives blood its red color. Normal range for hemoglobin is different between the sexes and is approximately 13 to 18 grams per deciliter for men and 12 to 16 for women (international units 8.1 to 11.2 millimoles/liter for men, 7.4 to 9.9 for women). * Hematocrit (Hct). This is the ratio of the volume of red cells to the volume of whole blood. Normal range for hematocrit is different between the sexes and is approximately 45% to 52% for men and 37% to 48% for women. This is usually measured by spinning down a sample of blood in a test tube, which causes the red blood cells to pack at the bottom of the tube. * Mean corpuscular volume (MCV) is the average volume of a red blood cell. This is a calculated value derived from the hematocrit and red cell count. Normal range may fall between 80 to 100 femtoliters (a fraction of one millionth of a liter). * Mean Corpuscular Hemoglobin (MCH) is the average amount of hemoglobin in the average red cell. This is a calculated value derived from the measurement of hemoglobin and the red cell count. Normal range is 27 to 32 picograms. * Mean Corpuscular Hemoglobin Concentration (MCHC) is the average concentration of hemoglobin in a given volume of red cells. This is a calculated volume derived from the hemoglobin measurement and the hematocrit. Normal range is 32% to 36%. * Red Cell Distribution Width (RDW) is a measurement of the variability of red cell size and shape. Higher numbers indicate greater variation in size. Normal range is 11 to 15. * Platelet count. The number of platelets in a specified volume of blood. Platelets are not complete cells, but actually fragments of cytoplasm (part of a cell without its nucleus or the body of a cell) from a cell found in the bone marrow called a megakaryocyte. Platelets play a vital role in blood clotting. Normal range varies slightly between laboratories but is in the range of 150,000 to 400,000/ cmm (150 to 400 x 109/liter). * Mean Platelet Volume (MPV). The average size of platelets in a volume of blood. What are the functions of the cells in a complete blood count (CBC)? The cells in the CBC (white blood cells, red blood cells, and platelets) have unique functions. Generally speaking, white blood cells are an essential part of the immune system and help the body fight infections. Each different component of the white blood cell (the WBC differential) plays a specific role in the immune system. Red blood cells are essential in transporting oxygen to all the cells in the body to serve their functions. The hemoglobin molecule in the red blood cell is the vehicle for the transportation of oxygen. Platelets are a part of the blood clotting system in the body and help in preventing bleeding. What is the complete blood count (CBC) used for? Your doctor may order this test for a variety of reasons. It may be a part of a routine check-up or screening, or as a follow-up test to monitor certain treatments. It can also be done as a part of an evaluation based on a patient's symptoms. For example, a high WBC count (leukocytosis) may signify an infection somewhere in the body or, less commonly, it may signify an underlying malignancy. A low WBC count (leukopenia) may point toward a bone marrow problem or related to some medications, such as chemotherapy. A doctor may order the test to follow the WBC count in order to monitor the response to a treatment for an infection. The components in the differential of the WBC count also have specific functions and if altered, they may provide clues for particular conditions. A low red blood cell count or low hemoglobin may suggest anemia, which can have many causes. Possible causes of high red blood cell count or hemoglobin (erythrocytosis) may include bone marrow disease or low blood oxygen levels (hypoxia). A low platelet count (thrombocytopenia) may be the cause of prolonged bleeding or other medical conditions. Conversely, a high platelet count (thrombocytosis) may point toward a bone marrow problem or severe inflammation. Functions of blood * It supplies oxygen to cells and tissues. * It supplies essential nutrients to cells, such as amino acids, fatty acids, and glucose. * It removes carbon dioxide, urea and lactic acid (waste products) * Its white blood cells have antibodies which defend us from infection and foreign bodies. * It has specialized cells, such as platelets, which help the blood to clot (coagulate) when we are bleeding. * It transports hormones - chemicals released by a cell in one part of the body that sends out messages that affect cells elsewhere in the body. * It regulates our acidity (pH) levels. * It regulates our body temperature. When the weather is very warm or during strenuous exercise there will be increased blood flow to the surface, resulting in warmer skin and faster heat loss. When environmental temperatures drop, blood flow focuses more on the important organs deep inside the body. * It also has hydraulic functions - when a human is sexually aroused, engorgement (filling the area with blood) will result in a male erection and swelling of the female's clitoris. Blood cells are produced in the bone marrow White cells, red cells and platelets are made in the bone marrow - a jellylike substance that fills the cavities of bones. Bone marrow consists of fat, blood, and special cells (stem cells) that turn into the various kinds of blood cells. The main areas of bone marrow involved in the formation of blood cells are in the vertebrae, ribs, sternum, skull and hips. http://www.healthline.com/sw/gsa-hematology http://www.floridasbloodcenters.org/learn/aboutFaq.stml * Red Blood Cells * White Blood Cells * Platelets * Plasma * Lymph * Blood Types * Rh Factors Human blood is the body fluid circulated by the heart through the vascular system of the human body to deliver oxygen and nutrients to the body's cells and to transport waste products away from these cells. Blood is considered as a specialized form of connective tissue that is produces by the bones by a process called hematopoiesis. Human blood is red in color due to the presence of red blood cells containing the pigment hemoglobin. An average adult has about five liters of blood in his body, which accounts for seven percent of his body weight. Other functions of blood include providing immunity, coagulation, transport of hormones and regulating body temperature and pH. The constituents of blood are blood cells suspended in the fluid called blood plasma. Blood cells include erythrocytes or red blood cells, leukocytes or white blood cells and thrombocytes or platelets. All blood cells are produced in the bone marrow from a single cell called hematopoietic stem cell. Erythrocytes are the most numerous cells of all blood cells and range from 4.7 to 6.1 million cells per millimeter cube in males and from 4.2 to 5.4 million cells per millimeter cube in females. Red blood cells (RBCs) are biconcave in shape and contain no nucleus or organelles. They contain hemoglobin and their function is oxygen transport to body cells and carrying back carbon dioxide from these cells to the lungs. White Blood Cells (WBCs) constitute the immune system and range from 4,000 to 11,000 cells per millimeter cube. They are white in color and are much larger in size than the more numerous erythrocytes. They consist of granulocytes and agranulocytes. Granulocytes include neutrophils, eosinophils and basophils. Agranulocytes include lymphocytes and monocytes. Lymphocytes are of two types- B and T lymphocytes which produce antibodies against bacteria, toxins and other infectious agents and regulate immunity. Monocytes are the largest of all WBCs and become tissue macrophages to remove foreign particles and protect against them. Hence they are known as phagocytes. Granulocytes are named after the staining characteristics of their granules. Neutrophils have segmented nuclei, eosinophils have two to four lobes nuclei whereas basophils have two lobed nuclei. Platelets range from 150,000 to 400,000 per micro liter. They help in formation of blood clot and prevent excessive bleeding. Plasma is the liquid component of blood in which blood cells are suspended. It is straw colored and makes up 55% of total blood volume. It is composed of mainly water with dissolved proteins, glucose, clotting factors, hormones, minerals and carbon dioxide. Serum proteins constitute serum albumin serum globulin, fibrinogen and prothrombin which can be separated by electrophoresis. Blood is a connective tissue containing suspended cells in its liquid component called plasma. Plasma constitutes 55% of blood volume and blood cells make up the remaining 45%.The types of Blood cells are red blood cells, white blood cells and platelets out of which RBCs are the most numerous and responsible for the red color of blood. Each component of blood has a specific function vital to life. 1. Which of the following statements is true concerning human blood? a) The blood of all normal humans contains red and white cells, platelets, and plasma. b) Some human populations normally lack the ability to produce plasma. c) Proteins are not normal components of human blood. Correct:The blood of all normal humans contains red and white cells, platelets, and plasma. ## CORRECT --> There are no populational or regional differences. All healthy people produce these 4 main blood components. 2. Erythrocyte is another name for a: a) red cell b) white cell c) platelet Correct: red cell ## CORRECT --> Erythrocyte literally means red cell in Greek. 3. Which of the following blood components provide the major defense for our bodies against invading bacteria and viruses? a) red cells b) white cells c) platelets Correct:white cells ## CORRECT --> There are numerous types of white cells, many of which function to seek out and destroy alien microbes in our bodies. Some other types of white cells have the function of getting rid of old unneeded blood cells. 4. The relatively clear liquid medium which carries the other cells of blood is called: a) lipid b) antibody c) plasma Correct:plasma ## CORRECT --> Most of blood`s volume is made up of plasma. As the heart pumps blood to cells throughout the body, the plasma brings them nourishment and removes the waste products of metabolism. It also transports the red and white cells as well as the platelets. 5. Which of the following are likely to increase in quantities when the body is under attack from bacteria? a) erythrocytes b) leukocytes c) thrombocytes Correct:leukocytes ## CORRECT --> In response to such an attack, the leukocytes, or white cells, normally appear at the site of infections in increasing numbers. They attack the invading bacteria and ultimately get rid of them if they are successful. 6. When blood clumps or forms visible islands in the still liquid plasma, it is called: a) clotting b) agglutination c) none of the above Correct:agglutination ## CORRECT --> Agglutination is the result of red cells being stuck together by antibodies attaching on to antigens on the alien red cells. Within the body, this recognition-rejection process results in the bursting of alien red cells rather than agglutination. 7. Antigens are: a) found on the surface of red cells b) kinds of red cells that identify a blood type c) relatively large carbohydrate molecules d) a and b Correct:found on the surface of red cells ## CORRECT --> They are relatively large protein molecules that identify a blood type. Each antigen type has unique traits that, in a sense, make it like a lock that only a specific antibody key can fit. 8. Which of the following statements is true of antigen-antibody interactions? a) They are used by our bodies only to identify blood types. b) They are used to identify and reject microorganisms, such as viruses and bacteria, that invade our bodies. c) They are the way our blood clots when we are bleeding from an open wound. d) b and c Correct:They are used to identify and reject microorganisms, such as viruses and bacteria, that invade our bodies. ## CORRECT --> Microorganisms carry foreign antigens on their surfaces which stimulate the production of white cell antibodies that attack the antigens as a way of getting rid of the invading parasites and subsequently develop an immunity to future attacks. 9. Most of the volume of normal human blood is composed of: a) red cells b) hemoglobin c) plasma d) white cells Correct:plasma CORRECT --> The liquid component of blood that we call plasma is the most abundant substance in blood. However, red cells are a close second. Practice Quiz for ABO blood types 1. In the ABO blood system, you normally can be type: a) A b) B c) ABO d) A, B, AB, or O e) all of the above Correct: A, B, AB, or O ## CORRECT --> You can be type A, B, AB, or O but not ABO. 2. Which of the following statements is true regarding the ABO blood system? a) People who have the A antigen normally would not produce the anti-A antibody. b) People who are type AB normally produce both anti-A and anti-B antibodies. c) The only ABO type blood that normally does not have either A or B antigens is AB. Correct: People who have the A antigen normally would not produce the anti-A antibody. ## CORRECT --> If they produced anti-A antibodies, it would destroy their own blood. However, they do normally produce anti-B antibodies since B type blood would be alien to them. 3. The universal blood donors for the ABO system are type: a) A b) B c) O d) AB Correct: O ## CORRECT --> Since type O blood normally lacks both A and B antigens, it will not be recognized as an alien type by the blood of anyone. As a result, anyone usually can be transfused with O blood without concern about rejection for this blood group. 4. Which of the following statements is true about the ABO blood system? a) It was discovered in the 1950's. b) It was discovered by Karl Landsteiner c) Few people are actually typed for this system because of the difficulty of the procedure and high cost. d) a and b Correct:It was discovered by Karl Landsteiner ## CORRECT --> Karl Landsteiner discovered the ABO system in 1900 and 1901 while trying to understand why blood transfusions sometimes saved lives and at other times caused death. 5. An individual's ABO blood type is normally determined by: a) Genetic inheritance and environmental influences during life b) Environmental influences alone c) The inheritance of 1 of 3 possible alleles (A, B, or O) from each parent Correct:The inheritance of 1 of 3 possible alleles (A, B, or O) from each parent ## CORRECT --> In most cases these alleles are totally responsible for determining blood type phenotypes. The inheritance usually follows simple Mendelian patterns. However, there are rare exceptions such as the Bombay Phenotype described in the tutorial. 6. In determining the phenotype for the ABO blood system: a) O is dominant over A b) B is dominant over A c) O is recessive d) all of the above Correct: O is recessive ## CORRECT --> The rules of dominance for the ABO system are that A and B are both dominant over O (i.e., O is recessive) and A and B are codominant. 7. If one of your parents is blood type A and the other is type B, which of the following blood types would you likely be? a) A b) B c) O d) AB e) any of the above Correct:any of the above ## CORRECT --> Since you could inherit A or O alleles from one parent and B or O alleles from the other, you could be any of the 4 ABO types. Look at the other answers to see how this could be true. |