Red blood cells are the most numerous blood cell, about 5,, per microliter. Their color is caused by hemoglobin, which accounts for nearly all of the red cell volume. Hemoglobin is the critical protein that transports oxygen from our lungs to the tissues. Red cells are normally shaped as round, biconcave discs. With microscopic examination, they look like a red or orange tire with a thin, almost transparent center.
White blood cells are the largest of the blood cells but also the fewest. There are only 5, to 10, white blood cells per microliter. There are several different types of white cells but all are related to immunity and fighting infection. Platelet Production Platelets are produced in the bone marrow, the same as the red cells and most of the white blood cells. Platelet Structure Platelets are actually not true cells but merely circulating fragments of cells.
Platelet Function In addition to being the smallest blood cell, platelets are also the lightest. Disorders of Platelet Function The most common disorder of platelet function is caused by aspirin. Disorders of Platelets Number: Too Many Platelets Rare conditions result in the bone marrow producing too many platelets, sometimes as many as one million or two million per microliter.
Almost all medications can cause bad allergic reactions in sensitive people, but these reactions are rare. Most commonly, drugs may cause a red rash in sensitive people. Drugs can also cause serious reactions with blood platelets. In these reactions, drugs stick to the platelet surface, and this combination of the drug bound to the platelet can be recognized by the body as a foreign substance and the body then makes an antibody to the drug-coated platelets, and all platelets can be destroyed.
When the drug is stopped, platelet destruction is stopped, and the platelet count returns to normal. But these drug-dependent antibodies can persist for many years, the same way that protective antibodies persist for many years after immunizations. So if the patient takes the drug again, the platelets are coated, the antibody reacts with the platelets and again the platelet count falls immediately to low levels.
Therefore recognition of a drug as the cause for thrombocytopenia is critical to avoid any further exposure to that drug. This is described in its own section on this website. The platelet count is not very low. Our opinion is that this is merely a normal adjustment of the platelet count during pregnancy, that the platelet counts of pregnant women, particularly near the end of pregnancy and at the time of delivery, all shift down a little bit.
A reason for this is that the plasma volume is increased during pregnancy, and therefore the platelets are simply diluted in the larger volume of plasma. This is the explanation for why the blood hemoglobin concentration is also a little lower during pregnancy. Our opinion is that this is not a health problem and it does not require any additional testing or care. Thrombotic microangiopathies TMA - These disorders are the result of abnormal blood clotting in the smallest blood vessels arterioles, capillaries throughout all of the body.
There are multiple causes of these syndromes. All are uncommon. Granular Myeloid White Blood Cells. Agranular Myeloid White Blood Cells.
Lymphoid White Blood Cells. When you select "Subscribe" you will start receiving our email newsletter. Use the links at the bottom of any email to manage the type of emails you receive or to unsubscribe. See our privacy policy for additional details. Learn Site. No Nucleus? Red blood cells take seven days to develop from stem cells called hemocytoblasts. Inactivated platelets are irregular disc-shaped structures.
Activated platelets are round with projections. Platelets clump at sites of injury to prevent blood loss. Visible Body Biology Learn more. Originally developed to treat patients suffering from anemia, renal failure, or cancer treatment, large quantities of EPO can be generated by recombinant DNA technology. Synthetic EPO is injected under the skin and can increase hematocrit for many weeks.
It may also induce polycythemia and raise hematocrit to 70 or greater. This increased viscosity raises the resistance of the blood and forces the heart to pump more powerfully; in extreme cases, it has resulted in death. Blood doping has become problematic in many sports, especially cycling. Lance Armstrong, winner of seven Tour de France and many other cycling titles, was stripped of his victories and admitted to blood doping in The simple act of increasing the number of red blood cells in blood may be associated with hyperviscosity syndrome which is characterized by increased blood viscosity and decreased cardiac output and blood flow velocity which results in the reduction of peripheral oxygen delivery.
This increases the chances of heart attack, stroke, phlebitis, and pulmonary embolism, which has been seen in cases where there is too much blood reintroduced into the blood stream. Because blood doping increases the volume of red blood cells, it effectively introduces a condition called polycythemia, a blood disorder that has known adverse outcomes such as heart attacks or strokes.
Blood contamination during preparation or storage is another issue. Contamination was seen in 1 in every , transfusions of red blood cells in Blood contamination can lead to septicemia or an infection that affects the whole body. When cyclist Lance Armstrong admitted he used performance enhancing drugs, the practice of blood doping hit the media spotlight. But how exactly does it boost performance? Experts at Mayo Clinic explore the science behind blood doping in the following video.
These tests and procedures are often used to assist in the diagnosis and treatment of various severe forms of anemia, such as thalassemia major and sickle cell anemia, as well as some types of cancer, specifically leukemia. In the past, when a bone marrow sample or transplant was necessary, the procedure would have required inserting a large-bore needle into the region near the iliac crest of the pelvic bones os coxae. This location was preferred, since its location close to the body surface makes it more accessible, and it is relatively isolated from most vital organs.
Unfortunately, the procedure is quite painful. Monocytes and lymphocytes are agranulocytes. Neutrophils, the most numerous leukocytes, are phagocytic and have light-colored granules. Eosinophils have granules and help counteract the effects of histamine. Basophils secrete histomine and heparin and have blue granules. In the tissues, they are called mast cells.
Lymphocytes are agranulocytes that have a special role in immune processes. Some attack bacteria directly; others produce antibodies. Thrombocytes, or platelets, are not complete cells, but are small fragments of very large cells called megakaryocytes.
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