Hematology

The type of nuclear reproduction seen in the megakaryocytes is:

• polypoid division

• endomitosis

• meiosis

• binary fission

In differentiating the maturation stages of the megakaryocytic cells, emphasis should be placed on the ___.

• cytoplasmic appearance

• number of nuclei

• chromatin structure

• size of the cell

Identify this platelet precursor:

*Single nucleus, fine chromatin, nucleoli

*Absence of cytoplasmic granules

*No visible thrombocytes

• megakaryoblast

• promegakaryocyte

• megakaryocyte

• metamegakaryocyte

Identify this platelet precursor:

*Four or more nuclei

*Aggregated cytoplasmic granules

*With visible thrombocytes

• megakaryoblast

• Promegakaryocyte

• megakaryocyte

• metamegakaryocyte

An OIF containing 100 RBCs should have ____ platelets, whereas field with 200 RBCs should have ___ platelets.

• 3 to 10; 5 to 20

• 8 to 20; 20 to 50

• 5 to 20; 10 to 40

• 20 to 40; 50 to 100

Patients refractory to platelet transfusion:

• Patients with aplastic anemia or acute leukemia who have received long-term platelet support, may developed platelet alloimmunization

• Most alloantibodies are directed against HLA antigens

• Leukocyte-poor-platelet concentrates may alleviate the problem for some recipients

• all of these

Patients requiring extensive transfusions develop thrombocytopenia by two mechanism: acute blood loss and dilution pf their own platelet pool. Extensive blood transfusion often is accompanied by thrombocytopenia, the degree of which is ____ proportional to the number of units transfused.

• directly

• inversely

Neonatal isoimmune thrombocytopenia is caused by:

• transplacental passage of maternal IgG antibodies directed against fetal antigens inherited from the father and absent on the mother's platelets

• after viral illness such as measles, chickenpox, rubella or IM

• treatment with quinidine, quinine, gold salts, sulfonamides, chloroquine and rifampicin

• increased platelet sequestration by the spleen

Poor man's platelet aggregation test:

• platelet aggregometer

• blood film taken from a capillary puncture

A white cell count above ___ is termed leukocytosis.

• 9.0 x 10⁹/L

• 10.0 x 10⁹/L

• 11.0 x 10⁹/L