Hematology Flashcards
HEMATOLOGY
The clinical and laboratory discipline that pertains to the anatomy, physiology, pathology, symptomatology, and therapeutics related to the blood and blood-forming tissues.
Peripheral blood accessible via
venipuncture and fingerstick
Bone marrow accessible only through a?
bone marrow aspiration
Bone marrow is often referred to as:
Myeloid, Myelogenous, or Intramedullary tissue
COMPLETE BLOOD COUNT most common hematologic test t/f?
True
HEMATOPOIESIS
The formation and development of all types of blood cells from their parental precursors
Embryo Site of hematopoiesis
yolk sac then liver
3rd to 7th month Site of hematopoiesis
spleen
4th and 5th months Site of hematopoiesis
marrow cavity - esp. granulocytes and platelets
7th month Site of hematopoiesis
marrow cavity - erythrocytes
Birth to maturity Birth Site of hematopoiesis
mostly bone marrow; spleen and liver when needed
Birth to maturity Site of hematopoiesis
number of active sites in bone marrow decreases but retain ability for hematopoiesis
Adult Site of hematopoiesis
bone marrow of skull, ribs, sternum, vertebral column, pelvis, proximal ends of femurs
Red cells require how many days for bone marrow development?
5-6 days
The nucleus disappears after 2 to 3 days creating
marrow reticulocytes
blood reticulocytes
Maturing red cells enter the circulating blood very promptly, even before the last maturational events have occurred.
Red cells remain in the circulation for about?
120 days before senescence and destruction.
Reticulocyte
The last immature stage of RBC maturation that occurs after the nucleus is extruded in the bone marrow.
4. A reticulofilamentous material appears when a reticulocytes is stained with a supravital stain
Reticulocyte are Slightly larger than mature erythrocyte because?
the cell is still maturing
Reticulocyte Contains residual fragments of cytoplasmic RNA and fragments of mitochondria which give the cell an…
polychromatic (polychromatophilic, polychromasia) appearance when stained with Wright stain
A reticulofilamentous material appears when a reticulocytes is…
a reticulocytes is stained with a supravital stain
Reticulocytes finish maturing within 1 to 2 days after?
entering the peripheral circulation
Reticulocyte are what % of circulating red cells
0.5 to 2.5%
Reticulocyte counts are commonly used in the differential diagnosis of various types
of anemia and in monitoring the recovery in factor deficiency anemias.
Erythropoietin are Produced by
kidney peritubular interstitial cells and can be assayed
Erythropoietin Effective functions
a. Increases the number of stem cells that commit to rubriblasts
b. Speeds maturation time by perhaps 20 to 30%
c. Early release of immature cells into peripheral circulation
Hemoglobin is synthesized within the maturing nucleated red cell within?
the bone marrow via a series of biochemical enzymatically driven reactions intimately involving the mitochondria
Heme is produced when iron is?
enzymatically inserted into protoporphyrin
Polyribosomes produce globin
(polypeptide) chains in pairs
Each globin chain provides a site
for insertion of one heme molecule
Four globin chains (2 pairs) + four heme molecules constitutes
hemoglobin
Various combinations of pairings of globin chains produce different types of hemoglobin based upon?
their speed in an electophoretic separation
Types of hemoglobin can be identified and quantified by a test called
Hemoglobin Electrophoresis
t/f? Iron is essential for erythropoiesis
true
Approximately 10% of ingested iron is absorbed via?
the proximal small intestine; remainder excreted in the feces
Small amounts of absorbed iron is excreted into the?
urine
Once absorbed into the plasma, iron is complexed with transferrin and is transported to the bone marrow for?
hemoglobin synthesis, and other tissues for the production of myoglobin, enzymes, coenzymes.
t/f ron is stored as both hemosiderin and ferritin?
true
There are FOUR tests that reflect the status of iron metabolism:
a. Serum iron concentration (SI)
b. Total iron binding capacity (TIBC)
c. % saturation of transferrin (% sat or TSAT)
d. Serum ferritin concentration
Serum Iron Concentration (SI)
SI is the concentration of circulating iron that is bound to transferrin. SI alone is not a good indicator of iron metabolism status as there are physiological (non-pathological) causes of altered concentrations.
Total Iron Binding Capacity (TIBC)
The TIBC is an indirect assay of transferrin concentration performed by measuring the amount of iron (added in vitro) needed to totally saturate the unbound iron-binding sites on the transferrin molecules. Normally, approximately one-third of the binding sites of transferrin are bound with iron.
Transferrin Saturation (% saturation, Tsat)
This is a calculated value estimating the percentage of binding sites on transferrin that are bound with iron.
Serum Ferritin
Ferritin is the body’s major iron storage compound. It is found in nearly all cells of the body. The major sites of storage, which are directly available for erythropoiesis, are the hepatocytes, spleen, and bone marrow.
GRANULOPOIESIS
Maturation of the leukocytes that contain granules (neutrophils, eosinophils, basophils)
BAND NEUTROPHILS
An immature form of neutrophil which is observed both within and outside of the bone marrow
SHIFT TO THE LEFT
Any increase in the numbers of immature neutrophils observed in the peripheral circulation. Often indicative of acute infection or other causes of neutrophilia.
LYMPHOPOIESIS
Growth and maturation of lymphocytes
Lymphocytes mature within the bone marrow and is mediated
by a poorly understood control mechanism
Lymphocytes enter the circulation and then repopulate?
lymph nodes and lymphatic tissues
Lymphocytes are “conditioned” by either :
the thymus (T-lymphocytes; cellular immunity) or the bone marrow (B-lymphocytes; humoral immunity) which further differentiate into plasma cells
ATYPICAL LYMPHOCYTES
Morphologically abnormal appearing (T) lymphocytes usually observed in the peripheral blood of an immunologically stimulated patient, most often viral infections.
MEGAKARYOPOIESIS
Production of thrombocytes (platelets)
EVALUATION OF HEMATOPOIESIS
- Complete Blood Count
- Reticulocyte Count
- Bone Marrow Aspiration and Biopsy
COMPLETE BLOOD COUNT Specimen collection considerations:
- Routine venipuncture most common method of collecting whole blood for CBC; EDTA anticoagulated whole blood specimen
- Micro-method via a fingerstick is available
- No special time of collection
- No fasting or other specific patient preparation is necessary
- Patient may be sitting or supine
- Must be sure that the patient is being regularly adjusted
What is the name of WBC when they are elevated and decreased?
Elevated; neutrophilia, lymphocytosis, moncytosis, eosinophilia, basophilia. Decreased; neutropenia, lymphocytopenia, moncytopenia, eosinopenia, basopenia.
What can cause neutophilia?
physical or emotional stress, acute suppurative infeciton, myelocytic leukemia, inflammatory disorders.
What can cause lymphocytosis?
Chronic bacterial infections, viral infections, lymphocytic leukemias
What can cause moncytosis?
Chronic inflammatory disorders, tuberculosis.