HematopoiesisHematopoiesis(Blood Cell Formation)
• All blood cells differentiate from a common source, hemocytoblast stem cells in red bone marrow.
AnemiaAnemia• A decrease in the oxygen-carrying
ability of the blood. Caused by:
1) Excessive RBC destruction (hemolysis)
2) Blood loss (acute or chronic)
3) Inadequate RBC production
Hemorrhagic AnemiaHemorrhagic Anemia• Decrease in RBC
number
• Sudden hemorrhage
Hemolytic AnemiaHemolytic Anemia• Decrease in RBC
number
• Lysis of RBCs as a result of bacterial infections
Pernicious AnemiaPernicious Anemia• Decrease in RBC
number
• Lack of Vitamin B12
Aplastic AnemiaAplastic Anemia• Decrease in RBC
number
• Depression or destruction of bone marrow by cancer, radiation, or certain medications
Iron Deficiency AnemiaIron Deficiency Anemia• Inadequate
hemoglobin content in RBCs
• Lack of iron in diet or slow/prolonged bleeding which depletes iron reserves needed to make hemoglobin
Sickle Cell AnemiaSickle Cell Anemia• Abnormal
hemoglobin in RBCs
• Genetic defect leads to abnormal hemoglobin, which becomes sharp and sickle shaped.
PolycythemiaPolycythemia•Excessive or abnormal increase in the number of RBCs
•May result from bone marrow cancer or from living at high altitudes.
LeukemiaLeukemia•Excessive production of abnormal WBCs
•Bone marrow is cancerous and huge numbers of WBCs are turned out rapidly.
Infectious MononucleosisInfectious Mononucleosis•Excessive production of abnormal WBCs
Undesirable ClottingUndesirable Clotting•Thrombus – a clot that develops and persists in an unbroken blood vessel
•Embolus – if a thrombus breaks away from the vessel wall and floats freely in the blood stream
Bleeding DisordersBleeding Disorders•Thrombocytopenia results from an insufficient number of circulating platelets. Even normal movement cause spontaneous bleeding from small blood vessels.
•Hemophilia applies to several different hereditary bleeding disorders that result from a lack of any of the factors needed for clotting.
Developmental AspectsDevelopmental Aspects•Before birth there are many sites of blood cell formation including the liver and spleen among others. At seven months red marrow takes over and remains so throughout life.
•Fetal hand grasp
Developmental AspectsDevelopmental Aspects•Fetal hemoglobin has a greater ability to pick up oxygen since fetal blood is less oxygen rich than that of the mother. After birth these are replaced with RBCs with more typical hemoglobin.
•newborn
Developmental AspectsDevelopmental Aspects•If the fetal RBCs are destroyed at such a rapid rate that the immature liver cannot rid the body of hemoglobin breakdown products in the bile fast enough, the infant becomes jaundiced.
•Jaundiced baby
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