Hematological Disorders Flashcards
What three components can blood be seperated into?
Plasma (55%), buffy coat (<1%), erythrocytes and RBCs (45%)
What does plasma contain?
Ions, proteins (albumin most abundant), lipids, dissolved oxygen and Co2
What does the buffy coat contain?
WBC/leukocytes, platelets, neutrophils (not normally in healthy tissue) and B and T cells
What are the cells found in blood?
Erythrocytes, neutrophils, eosinophils, basophils, lymphocytes, monocytes, platelets
What are the two alterations of RBCs?
Low number= anemia, excess= polycythemia
What is sickle cell anemia?
Alteration of RBCs, take on a sickle shape through amino acid substitution of beta chains that result in altered function, sickle cells less resilient to wear and tear= increased destruction/shorter lifespan
What are the alterations in WBCs?
Increased number= leukocytosis, decreased number= leukopenia
What are the alterations in numbers of platelets?
Low= thrombocytopenia, high= thrombocythemia
What is the composure of RBCs?
Lack nuclei, are small, primarily composed of hemoglobin
What is the function of hemoglobin?
Binds easily and reversibly to oxygen, made up of four globin proteins (each associated with iron containing heme group)
What do RBCs lack?
Mitochondria, need glycolysis to produce energy (mitochondria needs O2 to make ATP, prevents tug of war with hemoglobin)
What is erythropoiesis?
Process of RBC production
Which organ secretes erythropoietin (hormone)?
Secreted by the kidneys in response to hypoxia, goes to bone marrow and can increase number of RBCs being produced
What nutrients are needed for RBC production?
Iron, Vit B12, riboflavin, folate
What is hematocrit?
Proportion of whole blood sample occupied by intact RBCs
What is the erythrocyte count (ERCs)?
of erythrocytes in specific volume of blood
What is MCV?
Mean RBC volume
What is MCH?
Average amount of hemoglobin per RBC
What is MCHC?
Mean hemoglobin concentration per RBC
What is RDW?
RBC distribution width, estimation of variability in cell size
What are the two pathways of the coagulation cascade?
Intrinsic and extrinsic
What is required for clot to occur?
Coagulation enzymes must assemble on negative surface (ex: platelet membrane), calcium needed to bridge b/t y-carboxylated proteins and membrane surface, vit K required for y-carboxylation*
What is anemia?
Reduction in total circulating erythrocyte number or decrease in the quality/quantity of hemoglobin, results in decreased oxygen carrying capacity
What do the endings cytic and chromic refer to?
Cytic= cell size, chromic= hemoglobin content
How is anemia diagnosed?
With peripheral blood smear, able to assess size, colour, shape
What is macrocytic-normochromic anemia?
Increased RBC volume, and normal hemoglobin concentration, caused by impaired DNA synthesis and repair in RBC precursors. Inability of DNA to be synthesized, lack of cell division= megaloblasts
What is pernicious anemia?
Failure to absorb sufficient Vit B12, form of macrocytic-normochromic anemia
What is needed for effective DNA synthesis?
Vit B12 and folate important
How does Vit B12 absorption occur?
B12 freed from food via stomach acid. Parietal cells produce intrinsic factor which complexes with Vit B12, can be taken up in the ileum, dissociates and is stored in liver
What are some potential causes of pernicious anemia?
Impaired absorption (ex: chronic atrophic gastritis= autoimmune disorder that destroys parietal cells), ileostomies, etc.
What would labs show in someone with pernicious anemia?
Increase in MCV, decrease in hematocrit, normal MCHC, low Vit B12 levels
What would the bone marrow show in someone with pernicious anemia?
Increased number of megaloblasts
What is folate essential for?
Very important for DNA synthesis, needed for nucleotide synthesis
How does folate deficient anemia occur?
Lack of folate ingestion (found in leafy green veggies), chronic diarrhea, alcoholism (alcohol prevents activation of folate in the liver)
What would lab work show with someone who has folate defiency anemia?
Increased MCV, decreased hematocrit, low serum folate levels
What would the bone marrow biopsy show in someone with FDA?
Megaloblasts
What is microcytic-hypochromic anemia?
Smaller RBCs with less hemoglobin
What are two main causes of microcytic-hypochromic anemias?
Iron deficiency anemia and sideroblastic anemia
What is iron-deficiency anemia?
Need adequate amount of iron for hemoglobin production, obtained through diet in either non-heme or heme forms (preferred form)
Where is iron in the body?
75% in RBCs, some in liver attached to ferritin (a protein)
How can non-heme iron be converted to preferred heme form?
Vitamin C ingestion alongside it, allows conversion
How is iron absorbed?
Taken up by intestinal epithelial cells in duodenum, needs acidic PH, transported into blood where it complexes with transferrin and allows it to be taken up
Is iron easily lost?
No-body is good at recycling it. Macrophages break down old RBCs, produce bilirubin (excreted in bile), iron sent back to bone marrow and re-used
What are some potential causes of iron deficiency anemia?
Blood loss, parasites, cancer, decreased stomach acidity, decreased intestinal transit time, malnutrition