The "River of Life
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Blood is composed of plasma and formed elements such as red blood cells, white blood cells, and platelets. Red blood cells are biconcave discs that contain hemoglobin and transport oxygen and carbon dioxide. White blood cells provide defense against pathogens through mechanisms like phagocytosis. Platelets help in blood clotting when blood vessels are damaged. All blood cells are produced through hematopoiesis, which occurs primarily in the bone marrow.
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The "River of Life
- 1. Blood
- 12. Blood flow
- 15. Albumin Structure Regulation of osmotic pressure
- 25. Genesis of Formed Elements
- 45. Proerythroblast or pronormoblast Basophilic erythroblast or Early Normoblast Polychromatophilic (or intermediate) Erythroblast or Normoblast Dividing Polychromatophilic Erythroblast or Normoblast Orthochromatic (Acidophilic) erythroblast Or Late Erythroblast Orthochromatic erythroblast Extruding Nucleus Reticulocyte Reticulocyte (brilliant cresyl blue dye) 1
- 50. Fate and destr-uction of RBCs
- 52. Regulation of RBC production A negative Feed back mechanism
- 58. Hb Abnormalities
- 61. FR= ferrireductase Daily Iron Loss Male: 1mg/day Females: 2mg/day Daily Iron Requirement Male: 1mg/day Females: 2mg/day
- 68. Missing H-gene so no fucose tranferase so no fucose and no H-antigen that Forms the base for A and B Antigen. Bombay phenotype No fucose
- 71. Rh Factor
- 87. Intrinsic Pathway Blood Trauma or contact with collagen XII (Hageman) Activated XII (XII a ) HMW Kininogen, Prekellikerein XI (PTA) Activated XI (XI a ) IX (PTC) Activated IX (IX a ) Ca ++ X (SPF) Activated X (X a ) Ca ++ VIII (AHF-A) VIIIa Thrombin Ca ++ Thrombin V Prothrombin Activator V a Prothrombin Thrombin or PF 3 Ca ++ (1) (2) (3) (4) (5)
- 88. Extrinsic Pathway Tissue trauma VII (Proconvertin) Activated VII (VII a ) X (SPF) Activated X (X a ) Ca ++ Ca ++ Thrombin V Prothrombin Activator V a Prothrombin Thrombin or PF 3 Ca ++ (1) (2) (3)
- 100. Blood Testing
Notas do Editor
- Speticemia(blood poisoning)
- 1- wbcs are only formed elements that are complete cells 2- rbcs remain in blood stream while wbcs can slip out--- diapedesis (Leaping across) , Monocytes and Neutorphils can do this 3- mature cells– neutorphils– attack bacteria and viruses even in blood stream 4- Immature cells– monocytes—little ability to fight infections---but after entering tissues can change into Macrophages that are capable of combating pathogens
- PHSC: a primitive, undifferentiated form of blood cell from which erythroblasts, lymphoblasts, myeloblasts, and other immature blood cells are derived, capable of self-renewal An early branching of the pathway divides the lymphoid stem cells which produce lymphocytes from the myeloid stem cells which give rise to all other formed elements.
- 1-Thrombopoietin (leukemia virus oncogene ligand, megakaryocyte growth and development factor) , also known as THPO , is a glycoprotein hormone produced mainly by the liver and the kidney that regulates the production of platelets by the bone marrow . It stimulates the production and differentiation of megakaryocytes , the bone marrow cells that fragment into large numbers of platelets .[1] 2-In the liver it is produced by parenchymal cells and sinusoidal endothelial cells. In the kidney it is made by proximal convoluted tubule cells. Along with these it is made by striated muscle and stromal cells in the bone marrow . [1] In the liver, its production is augmented by interleukin 6 (IL-6). [1] Reference: Kaushansky K (2006). "Lineage-specific hematopoietic growth factors". N. Engl. J. Med. 354 (19): 2034–45. doi : 10.1056/NEJMra052706 . PMID 16687716 .
- i- The Bone Marrow Doesn't Make Enough Platelets Bone marrow is the sponge-like tissue inside the bones. It contains stem cells that develop into red blood cells, white blood cells, and platelets. When stem cells are damaged, they don't grow into healthy blood cells. Several conditions or factors can damage stem cells. Cancer Cancer, such as leukemia (lu-KE-me-ah) or lymphoma (lim-FO-ma), can damage the bone marrow and destroy blood stem cells. Cancer treatments, such as radiation and chemotherapy, also destroy the stem cells. Aplastic Anemia Aplastic anemia is a rare, serious blood disorder in which the bone marrow stops making enough new blood cells. This lowers the number of platelets in your blood. Toxic Chemicals Exposure to toxic chemicals, such as pesticides, arsenic, and benzene, can slow the production of platelets. Medicines Some medicines, such as diuretics and chloramphenicol, can slow the production of platelets. Chloramphenicol (an antibiotic) is rarely used in the United States. Common over-the-counter medicines, such as aspirin or ibuprofen, also can affect platelets. Alcohol Alcohol also slows the production of platelets. A temporary drop in platelets is common among heavy drinkers, especially if they're eating foods that are low in iron, vitamin B12, or folate. Viruses Chickenpox, mumps, rubella, Epstein-Barr virus, or parvovirus can decrease your platelet count for a while. People who have AIDS often develop thrombocytopenia. Genetic Conditions Some genetic conditions, such as Wiskott-Aldrich and May-Hegglin syndromes, can cause low numbers of platelets in the blood. 2-The Body Destroys Its Own Platelets A low platelet count can occur even if the bone marrow makes enough platelets. The body may destroy its own platelets due to autoimmune diseases, certain medicines, infections, surgery, pregnancy, and some conditions that cause too much blood clotting. Autoimmune Diseases With autoimmune diseases, the body's immune system destroys its own platelets. One example of this type of disease is called idiopathic thrombocytopenic purpura , or ITP. In most cases, the body's immune system is thought to cause ITP. Normally, your immune system helps your body fight off infections and diseases. But if you have ITP, your immune system attacks and destroys its own platelets—for an unknown reason. Other autoimmune diseases that destroy platelets include lupus and rheumatoid arthritis. Medicines A reaction to some medicines can confuse your body and cause it to destroy its platelets. Any medicine can cause this reaction, but it happens most often with quinine, antibiotics that contain sulfa, and some medicines for seizures, such as Dilantin,® vancomycin, and rifampin. Heparin is a medicine commonly used to prevent blood clots. But an immune reaction may trigger the medicine to cause blood clots and thrombocytopenia. This condition is called heparin-induced thrombocytopenia (HIT). HIT rarely occurs outside of a hospital. In HIT, the body's immune system attacks a substance formed by heparin and a protein on the surface of the platelets. This attack activates the platelets and they start to form blood clots. Blood clots can form deep in the legs , or a clot can break loose and travel to the lungs . Infection A low platelet count can occur after blood poisoning from a widespread bacterial infection. A virus, such as mononucleosis or cytomegalovirus, also can cause a low platelet count. Surgery Platelets can be destroyed when they pass through man-made heart valves, blood vessel grafts, or machines and tubing used for blood transfusions or bypass surgery . Pregnancy About 5 percent of pregnant women develop mild thrombocytopenia when they're close to delivery. The exact cause isn't known for sure. Rare and Serious Conditions That Cause Blood Clots Some diseases can cause a low platelet count. Two examples are thrombotic thrombocytopenic purpura (TTP) and disseminated intravascular clotting (DIC). TTP is a rare blood condition. It causes blood clots to form in the body's small blood vessels, including vessels in the brains, kidneys, and heart. DIC is a rare complication of pregnancy, severe infections, or severe trauma. Tiny blood clots form suddenly throughout the body. In both conditions, the blood clots use up many of the blood's platelets. The Spleen Holds On to Too Many Platelets Usually, one-third of the body's platelets are held in the spleen. If the spleen is enlarged, it will hold on to too many platelets. This means that not enough platelets will circulate in the blood. An enlarged spleen is often due to severe liver disease—such as cirrhosis (sir-RO-sis) or cancer. Cirrhosis is a disease in which the liver is scarred. This prevents it from working properly. An enlarged spleen also may be due to a bone marrow condition, such as myelofibrosis (MI-eh-lo-fi-BRO-sis). With this condition, the bone marrow is scarred and isn't able to make blood cells.
- 1- Males: Testosteron from leyding cells of testes, Increased BMR, increased oxygen demand, causes tissue hypoxia (low oxygen), this results in increased Erythropoietin release from kidneys (90%) (Juxta glumerular cells or mesangial cells) and liver (10%). Increased EPO, increased proerythroblasts formation from stem cells so increased RBCs. Females: Less testosteron so less RBCs. Infants: Greater need of oxygen as all their tissues are under a rapid growing process.
- 1- Basophil- A cell, especially a white blood cell, having granules that stain readily with basic dyes. 2-Polycrhromatophil- A young or degenerated red blood cell staining with acid, neutral, or basic dyes. Also called polychromatic cell , polychromatocyte . adj. Staining readily with acid, neutral, or basic dyes. 3- Orthochromatic - Sensitive to all colors except red. Staining with the same color as that of the dye used. Used of a cell or tissue.
- 1- Supravital dyes: Relating to or capable of staining living cells after their removal from a living or recently dead organism.
- Other cells that arise from monocyte are Osteoclast, Microglia – CNS, Langerhans cells – Epidermis, Kupffer cells - Liver
- Water soluble vitamins 1-Vitamin C (Ascorbic Acid) B1 (Thiamine), B2 (Riboflavin), B3 (Niacinamide, Niacin), B5 (Pantothenic acid), B6 (Pyridoxine), B7 (Biotin), B9 (Folic Acid (Folate) B12 (Cobolamine),
- 1 -The heme of their hemoglobin is split off from globin. Its core of iron is salvaged, bound to protein (as ferritin or hemosiderin), and stored for reuse. The balance of the heme group is degraded to bilirubin (bil″i-roo′bin), a yellow pigment that is released to the blood and binds to albumin for transport. Bilirubin is picked up by liver cells, which in turn secrete it (in bile) into the intestine, where it is metabolized to urobilinogen. Most of this degraded pigment leaves the body in feces, as a brown pigment called stercobilin. The protein (globin) part of hemoglobin is metabolized or broken down to amino acids, which are released to the circulation. Disposal of hemoglobin spilled from red blood cells to the blood (as occurs in sickle-cell anemia or hemorrhagic anemia) takes a similar but much more rapid course to avoid toxic buildup of iron in blood. Released hemoglobin is captured by the plasma protein haptoglobin and the complex is phagocytized by macrophages.
- 1- Hemostatic Imbalance: Rnal dialysis (Low EPO) Athletes Doping: 45%-65% , so blood becomes Thick, sticky sludge that can cause clotting, stroke, heart failure. Dehydration
- 1- 10 AA of delta chain are different from beta chain. 2- 37 AA of gamma chain are different from beta chain in sequence. And has less positive charges as compared to beta chain so less reaction with 2,3-BPG or DPG. 2,3-bisphosphoglycerate reacts with Hb in adults and reduces its binding affinity to O2 Fetal hemoglobin's affinity for oxygen is substantially greater than that of adult hemoglobin. Notably, the P50 value for fetal hemoglobin (i.e., the partial pressure of oxygen at which the protein is 50% saturated; lower values indicate greater affinity) is roughly 19 mmHg , whereas adult hemoglobin has a value of approximately 26.8 mmHg. As a result, the so-called "oxygen saturation curve", which plots percent saturation vs. pO2, is left-shifted for fetal hemoglobin in comparison to the same curve in adult hemoglobin.
- There are small amounts of hemoglobin A derivatives closely associated with hemoglobin A that represent glycated hemoglobins. One of these, hemoglobin A1c (HbA1c), has a glucose attached to the terminal valine in each β chain and is of special interest because the quantity in the blood increases in poorly controlled diabetes mellitus
- 2,3-bisphosphoglycerate reacts with Hb in adults and reduces its binding affinity to O2 Fetal hemoglobin's affinity for oxygen is substantially greater than that of adult hemoglobin. Notably, the P50 value for fetal hemoglobin (i.e., the partial pressure of oxygen at which the protein is 50% saturated; lower values indicate greater affinity) is roughly 19 mmHg, whereas adult hemoglobin has a value of approximately 26.8 mmHg. As a result, the so-called "oxygen saturation curve", which plots percent saturation vs. pO2, is left-shifted for fetal hemoglobin in comparison to the same curve in adult hemoglobin.
- 1-There are two copies of the α globin gene on human chromosome 16. In addition, there are five globin genes in tandem on chromosome 11 that encode β, γ, δ (Delta), ζ (zeeta), ε (epsilon) globin chains
- When an abnormal gene inherited from one parent, when the individual is heterozygous—half the circulating hemoglobin is abnormal and half is normal. When identical abnormal genes are inherited from both parents, homozygous all of the hemoglobin is abnormal. Many of the abnormal hemoglobins are harmless. However, some have abnormal O2 equilibriums. Others cause anemia. For example, hemoglobin S polymerizes at low O2 tensions, and this causes the red cells to become sickle-shaped, hemolyze, and form aggregates that block blood vessels. The result is the severe hemolytic anemia known as sickle cell anemia. Heterozygous individuals have the sickle cell trait and rarely have severe symptoms, but homozygous individuals develop the full-blown disease. The sickle cell gene is an example of a gene that has persisted and spread in the population. It originated in the black population in Africa, and it confers resistance to one type of malaria. This is an important benefit in Africa, and in some parts of Africa 40% of the population have the sickle cell trait. In the United States black population its incidence is about 10%. Hemoglobin F has the ability to decrease the polymerization of deoxygenated hemoglobin S, and hydroxyurea causes hemoglobin F to be produced in children and adults. It has proved to be a very valuable agent for the treatment of sickle cell disease. In patients with severe sickle cell disease, bone marrow transplantation has been carried out and the patients have generally done well, though more study is needed.
- Iron Metabolism and Erythropoiesis Roughly 2/3 of the body’s iron pool (ca. 2 g in women and 5 g in men) is bound to hemoglobin (Hb). About 1/4 exists as stored iron (ferritin, hemosiderin), the rest as functional iron (myoglobin, iron-containing enzymes). Iron losses from the body amount to about 1 mg/day in men and up to 2 mg/day in women due to menstruation, birth, and pregnancy. Iron absorption occurs mainly in the duodenum and varies according to need . The absorption of iron supplied by the diet usually amounts to about 3 to 15% in healthy individuals, but can increase to over 25% in individuals with iron deficiency. A minimum daily iron intake of at least 10–20 mg/day is therefore recommended (women > children > men). Iron absorption Heme-Fe++: Fe(II) supplied by the diet (hemoglobin,myoglobin found chiefly in meat and fish) is absorbed relatively efficiently as a heme-Fe(II) upon protein cleavage. With the aid of hemeoxygenase , Fe in mucosal cells cleaves from heme and oxidizes to Fe(III). The tri-ferric form either remains in the mucosa as a ferritin-Fe(III) complex and returns to the lumen during cell turnover or enters the bloodstream. Non-heme-Fe can only be absorbed as Fe2+. Therefore, non-heme Fe+++ must first be reduced to Fe2+ by ferrireductase (FR;) and ascorbate on the surface of the luminal mucosa . Fe2+ is probably absorbed through secondary active transport via an Fe2+-H+ symport carrier (DCT1) (competition with Mn2+, Co2+, Cd2+, etc.). A low chymous pH is important since it (a) increases the H+ gradient that drives Fe2+ via DCT1 into the cell and (b) frees dietary iron from complexes. The absorption of iron into the bloodstream is regulated by the intestinal mucosa . When an iron deficiency exists, aconitase (an iron-regulating protein) in the cytosol binds with ferritin- mRNA, thereby inhibiting mucosal ferritin translation. As a result, larger quantities of absorbed Fe(II) can enter the bloodstream.Fe(II) in the blood is oxidized to Fe(III) by ceruloplasmin (and copper). It then binds to apotransferrin , a protein responsible for iron transport in plasma . Transferrin (= apotransferrin loaded with 2 Fe +3 ), is taken up by endocytosis into erythroblasts and cells of the liver, placenta, etc. with the aid of transferrin receptors . Once iron has been released to the target cells, apotransferrin again becomes available for uptake of iron from the intestine and macrophages. Iron storage and recycling Ferritin ,( Ferritin is a globular protein complex consisting of 24 protein subunits and is the main intracellular iron storage protein in both prokaryotes and eukaryotes , keeping it in a soluble and non-toxic form. Ferritin which is not combined with iron is called apoferritin ). one of the chief forms in which iron is stored in the body, occurs mainly in the intestinal mucosa, liver, bone marrow, red blood cells, and plasma. It contains binding pockets for up to 4500 Fe3+ ions and provides rapidly available stores of iron (ca. 600 mg), whereas iron mobilization from hemosiderin is much slower (250mg Fe in macrophages of the liver and bone marrow). Hb-Fe and heme-Fe released from malformed erythroblasts (so-called inefficient erythropoiesis) and hemolyzed red blood cells bind to haptoglobin and hemopexin, respectively. They are then engulfed by macrophages in the bone marrow or in the liver and spleen, respectively, resulting in 97% iron recycling . An iron deficiency inhibits Hb synthesis, leading to hypochromic microcytic anemia: MCH "26 pg, MCV "70 fL, Hb "110 g/L. The primary causes are: ! blood loss (most common cause); 0.5mg Fe are lost with each mL of blood; ! insufficient iron intake or absorption; ! increased iron requirement due to growth, pregnancy, breast-feeding, etc.; ! decreased iron recycling (due to chronic infection); ! apotransferrin defect (rare cause). Iron overload most commonly damages the liver, pancreas and myocardium (hemochromatosis). If the iron supply bypasses the intestinal tract (iron injection),the transferrin capacity can be exceeded and the resulting quantities of free iron can induce iron poisoning. B12 vitamin (cobalamins) and folic acid are also required for erythropoiesis (! B ). Deficiencies lead to hyperchromic anemia (decreased RCC, increased MCH). The main causes are lack of intrinsic factor (required for cobalamin resorption) and decreased folic acid absorption due to malabsorption (see also p. 260) or an extremely unbalanced diet. Because of the large stores available, decreased cobalamin absorption does not lead to symptoms of deficiencyuntil many years later, whereas folic acid deficiency leads to symptoms within a few months.
- Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on N -linked glycans on the mammalian , insect and plant cell surface Ceramides are a family of lipid molecules.
- It now appears that type O individuals have a single-base deletion in their corresponding gene. This creates an open reading frame, and consequently they produce a protein that has no transferase activity.
- 1- An important problem related to the Rh factor occurs in pregnant Rh– women who are carrying Rh+ babies. The first such pregnancy usually results in the delivery of a healthy baby. But, when bleeding occurs as the placenta detaches from the uterus, the mother may be sensitized by her baby’s Rh+ antigens that pass into her bloodstream. If so, she will form anti-Rh antibodies unless treated with RhoGAM before or shortly after she has given birth. (The same precautions are taken in women who have miscarried or aborted the fetus.) RhoGAM is a serum containing anti-Rh agglutinins. Because it agglutinates the Rh factor, it blocks the mother’s immune response and prevents her sensitization. If the mother is not treated and becomes pregnant again with an Rh+ baby, her antibodies will cross through the placenta and destroy the baby’s RBCs, producing a condition known as hemolytic disease of the newborn, or erythroblastosis fetalis. The baby becomes anemic and hypoxic. In severe cases, brain damage and even death may result unless transfusions are done before birth to provide the fetus with more erythrocytes for oxygen transport. Additionally, one or two exchange transfusions (see Related Clinical Terms) are done after birth. The baby’s Rh+ blood is removed, and Rh– blood is infused. Within six weeks, the transfused Rh– erythrocytes have been broken down and replaced with the baby’s own Rh+ cells.
- When an endothelial injury occurs, platelets adhere to subendothelial collagen fibers (! A1 ) bridged by von Willebrand’s factor (vWF), which is formed by endothelial cells and circulates in the plasma complexed with factor VIII. Glycoprotein complex GP Ib/IX on the platelets are vWF receptors. This adhesion activates platelets (! A2 ). They begin to release substances (! A3 ), some of which promote platelet adhesiveness (vWF). Others like serotonin, platelet- derived growth factor (PDGF) and thromboxane A2 (TXA2) promote vasoconstriction. Vasoconstriction and platelet contraction slow the blood flow. Mediators released by platelets enhance platelet activation and attract and activate more platelets: ADP, TXA2, platelet-activating factor (PAF). The shape of activated platelets change drastically (! A4 ). Discoid platelets become spherical and exhibit pseudopodia that intertwine with those of other platelets. This platelet aggregation (! A5 ) is further enhanced by thrombin and stabilized by GP IIb/IIIa. Once a platelet changes its shape, GP IIb/IIIa is expressed on the platelet surface, leading to fibrinogen binding and platelet aggregation. GP IIb/IIIa also increases the adhesiveness of platelets, which makes it easier for them to stick to subendothelial fibronectin.
- Prothrombin and Thrombin. Prothrombin is a plasma protein, an alpha2-globulin, having a molecular weight of 68,700. It is present in normal plasma in a concentration of about 15 mg/dl. It is an unstable protein that can split easily into smaller compounds, one of which is thrombin , which has a molecular weight of 33,700, almost exactly one half that of prothrombin. Prothrombin is formed continually by the liver, and it is continually being used throughout the body for blood clotting. If the liver fails to produce prothrombin, in a day or so prothrombin concentration in the plasma falls too low to provide normal blood coagulation. Vitamin K is required by the liver for normal formation of prothrombin as well as for formation of a few other clotting factors. Therefore, either lack of vitamin K or the presence of liver disease that prevents normal prothrombin formation can decrease the prothrombin level so low that a bleeding tendency results.
- DIC: Under homeostatic conditions, the body is maintained in a finely tuned balance of coagulation and fibrinolysis. The activation of the coagulation cascade yields thrombin that converts fibrinogen to fibrin; the stable fibrin clot being the final product of hemostasis. The fibrinolytic system then functions to break down fibrinogen and fibrin. Activation of the fibrinolytic system generates plasmin (in the presence of thrombin), which is responsible for the lysis of fibrin clots. The breakdown of fibrinogen and fibrin results in polypeptides called fibrin degradation products (FDPs) or fibrin split products (FSPs). In a state of homeostasis, the presence of thrombin is critical, as it is the central proteolytic enzyme of coagulation and is also necessary for the breakdown of clots, or fibrinolysis. In DIC, the processes of coagulation and fibrinolysis lose control, and the result is widespread clotting with resultant bleeding. Regardless of the triggering event of DIC, once initiated, the pathophysiology of DIC is similar in all conditions. One critical mediator of DIC is the release of a transmembrane glycoprotein called tissue factor (TF). TF is present on the surface of many cell types (including endothelial cells, macrophages, and monocytes) and is not normally in contact with the general circulation, but is exposed to the circulation after vascular damage. For example, TF is released in response to exposure to cytokines (particularly interleukin 1), tumor necrosis factor, and endotoxin. This plays a major role in the development of DIC in septic conditions. TF is also abundant in tissues of the lungs, brain, and placenta. This helps to explain why DIC readily develops in patients with extensive trauma. Upon activation, TF binds with coagulation factors that then trigger both the intrinsic and the extrinsic pathways of coagulation. The release of endotoxin is the mechanism by which Gram-negative sepsis provokes DIC. In acute promyelocytic leukemia, treatment causes the destruction of leukemic granulocyte precursors, resulting in the release of large amounts of proteolytic enzymes from their storage granules, causing microvascular damage. Other malignancies may enhance the expression of various oncogenes that result in the release of TF and plasminogen activator inhibitor-1 (PAI-1), which prevents fibrinolysis. Excess circulating thrombin results from the excess activation of the coagulation cascade. The excess thrombin cleaves fibrinogen, which ultimately leaves behind multiple fibrin clots in the circulation. These excess clots trap platelets to become larger clots, which leads to microvascular and macrovascular thrombosis. This lodging of clots in the microcirculation, in the large vessels, and in the organs is what leads to the ischemia, impaired organ perfusion, and end-organ damage that occurs with DIC. Coagulation inhibitors are also consumed in this process. Decreased inhibitor levels will permit more clotting so that a feedback system develops in which increased clotting leads to more clotting. At the same time, thrombocytopenia occurs because of the entrapment and consumption of platelets. Clotting factors are consumed in the development of multiple clots, which contributes to the bleeding seen with DIC. Simultaneously, excess circulating thrombin assists in the conversion of plasminogen to plasmin, resulting in fibrinolysis. The breakdown of clots results in excess amounts of FDPs, which have powerful anticoagulant properties, contributing to hemorrhage. The excess plasmin also activates the complement and kinin systems. Activation of these systems leads to many of the clinical symptoms that patients experiencing DIC exhibit, such as shock, hypotension, and increased vascular permeability. The acute form of DIC is considered an extreme expression of the intravascular coagulation process with a complete breakdown of the normal homeostatic boundaries. DIC is associated with a poor prognosis and a high mortality rate.
- Vitamin K is required by the liver cells for production of the clotting factors, and because vitamin K is produced by bacteria that reside in the intestines, dietary deficiencies are rarely a problem. However, vitamin K deficiency can occur if fat absorption is impaired, because vitamin K is a fat-soluble vitamin that is absorbed into the blood along with fats. In liver disease, the nonfunctional liver cells fail to produce not only the procoagulants but also bile, which is required for fat and vitamin K absorption.
- Sideroblastic Anemia: The body has iron available, but cannot incorporate it into hemoglobin. Sideroblasts are seen, which are nucleated erythrocytes with granules of iron in their cytoplasm. Cause: The common feature of these causes is a failure to completely form heme molecules, whose biosynthesis takes place partly in the mitochondrion . This leads to deposits of iron in the mitochondria that form a ring around the nucleus of the developing red blood cell . Sometimes the disorder represents a stage in evolution of a generalized bone marrow disorder that may ultimately terminate in acute leukemia. Toxins: lead or zinc poisoning Drug-induced: ethanol , isoniazid , chloramphenicol , cycloserine Nutritional: pyridoxine or copper deficiency Genetic: ALA synthase deficiency ( X-linked , associated with ALAS2 ) Myelophthisic anemia is a normocytic-normochromic anemia that occurs when normal marrow space is infiltrated and replaced by nonhematopoietic or abnormal cells. Causes include tumors, granulomatous disorders, and lipid storage diseases.