Hematology

Question 1

erythrocytes

Answer 1

bio-concave disk shape: thicker portion is red, thinner is pale
no nuclei at maturity
function for about 120 days before degradation by spleen
heme is oxygen binding compound with iron as import atom

Question 2

major hormone stimulating production of erythrocytes

Answer 2

erythropoietin (released by kidney)

Question 3

presence of nuclei in peripheral blood suggests

Answer 3

disease

Question 4

cytoplasm is filled with granules

Answer 4

granulocytes

Question 5

granulocytes

Answer 5

most common white blood cells

neutrophils, eosinophils, basophils

Question 6

most prevalent granulocytes

Answer 6

neutrophils

Question 7

most important granulocyte in inducing inflammation

Answer 7

neutrophils

Question 8

myelopoiesis

Answer 8

granulocyte production which is affected by many cytokines at different stages of development

Question 9

granules in granulocytes contain

Answer 9

enzymes, prostaglandins and mediators of inflammation

Question 10

basophils

Answer 10

very dark blue or purple granules when stained and associated with hypersensitivity reactions

Question 11

eosinophils

Answer 11

red stained granules with bi-lobed nuclei and are part of inflammatory response to parasites

Question 12

neutrophils

Answer 12

major function is in tissue

granules contain highly active enzymes that kill bacteria ingested by the neutrophil

first line of defense against bacterial pathogens

Question 13

platelets

Answer 13

fragment of large multi-nucleated cells-megakaryocytes

crucial to normal blood clotting

stimulated by multiple cytokines (especially thrombopoietin)

Question 14

maturation of RBCs

Answer 14

proerythroblast –> basophil erythroblast –> polychromatophil erythroblast –> orthochromatic erythroblast –> reticulocyte –> erythrocytes

Question 15

proerythroblast

Answer 15

formed from the CFU-E cells

Question 16

basophil erythroblast

Answer 16

very little hemoglobin, stain with basic dyes

Question 17

polychromatophil and orthochromatic erythroblasts stages

Answer 17

cells become filled with hemoglobin

nucleus condenses to a small size and is reabsorbed or extruded from cell

ER is also reabsorbed-at this stage called reticulocyte

Question 18

reticulocyte

Answer 18

contains a small amount of basophilic material (golgi, mitochondria, cellular organelles)

pass from marrow into blood (squeezing through pores in capillary membrane)

remaining basophilic material disappears within 24-48 hrs and cell is considered mature

Question 19

regulation of red blood cell production

Answer 19

total mass of RBC tightly regulated within the circulation

adequate number of RBC to transport oxygen

limit production so that cells do not impede blood flow

tissue oxygenation (most important regulator)

Question 20

erythropoietin stimulated RBC production

Answer 20

formed mainly in kidneys (90%) and liver (10%)

Question 21

renal tissue hypoxia leads to increased levels of

Answer 21

hypoxia-inducible factor-1 (HIF-1)

Question 22

HIF-1

Answer 22

binds to erythropoietin gene and increases synthesis of the hormone

Question 23

erythropoietin stimulates production of

Answer 23

proerythroblasts from hematopoietic stem cells

Question 24

sickle cell diseases

Answer 24

hemoglobinopathy caused by point mutation in beta-globin

hemolytic anemia

microvascular obstruction

ischemic tissue damage

Question 25

hemoglobinopathy caused by point mutation in beta-globin

Answer 25

promotes the polymerization of deoxygenated hemoglobin, red blood cell distortion

Question 26

sickle cell trait

Answer 26

heterozygous for HbS asymptomatic

Question 27

sickle cell disease

Answer 27

homozygous for HbS sympotomatic

Question 28

sickle cell diseases pathogenesis

Answer 28

interaction of HbS with other types of hemoglobin in the cell intracellular dehydration increased MCHC and facilitates sickling intracellular pH reduces oxygen affinity of hemoglobin leading to deoxygenation and sickling transit time of red cells through microvasculature

Question 29

interaction of HbS with other types of hemoglobin in the cell

Answer 29

HbA interferes with HbS polymerization HbF > HbA in inhibiting polymerization

Question 30

beta thalassemias

Answer 30

mutation that diminishes the synthesis of the beta-globin chains

Question 31

beta thalassemias molecular pathogenesis

Answer 31

B0 mutation associated with absent beta-globin synthesis B+ reduced but detectable beta-globin synthesis

Question 32

impaired synthesis of beta-globin results in

Answer 32

under-hemoglobinized, hyperchromic, microcytic red cells subnormal oxygen transport capacity diminished survival of RBCs and their precursors

Question 33

diminished survival of RBCs and their precursors

Answer 33

unpaired alpha-globin chains precipitate membrane damage occurs ineffective erythropoiesis splenic sequestration and hemolysis

Question 34

hereditary spherocytosis pathogenesis

Answer 34

caused by diverse mutations insufficiency of membrane skeletal components (lifespan decreased to 10-20 days) RBCs take on spheroidal shape and exhibit reduced deformability spheroidal RBCs are trapped in spleen and subject to macrophage digestion

Question 35

mutations that cause hereditary spherocytosis most commonly affects

Answer 35

ankyrin, band 3, spectrin, band 4.2 (tethering interactions that stabilize lipid bilayer)

Question 36

glucose-6-phosphate dehydrogenase (G6PD) deficiency

Answer 36

hereditary-recessive x-linked trait

Question 37

G6PD sequence of normal enzyme reactions

Answer 37

G6PD reduces NADP to NADPH NADPH facilitates oxidation or glutathione glutathione protects against oxidant injury by neutralizing H2O2

Question 38

G6PD deficiency pathogenesis

Answer 38

hemolysis of RBC is caused by exposures that generate oxidant stress oxidants in G6PD-deficient RBCs cause precipitates or inclusions in the RBC called Heinz bodies as RBCs with these inclusions pass through the spleen, macrophages pluck out the inclusions

Question 39

anemias of diminished erythropoiesis

Answer 39

megaloblastic anemias pernicious anemia: vitamin B12 deficiency iron deficiency anemia aplastic anemia

Question 40

peripheral blood findings shared by all megaloblastic anemias

Answer 40

RBCs are macrocytic and oval shaped variation in size and shape (anisocytosis and poikilocytosis) nucleated RBCs can appear in the blood neutrophils show nuclear hypersegmentation marrow is hypercellular impaired DNA synthesis causes most cell precursors to undergo apoptosis in the marrow

Question 41

pernicious anemia: vitamin B12 deficiency

Answer 41

absorption of vitamin B12 requires intrinsic factor secreted by parietal cells of the fundic mucosa

Question 42

pernicious anemia: vitamin B12 deficiency pathogenesis

Answer 42

results from autoimmune attack on the gastric mucosa chronic atrophic gastritis marked by loss of parietal cells and prevention of binding vitamin B12 and intrinsic factor

Question 43

iron deficiency anemia

Answer 43

hypochromic, microcytic anemia disappearance of stainable iron from macrophages (bone marrow) zone of pallor in RBCs is enlarged and observed only in a narrow peripheral rim of the RBC (peripheral blood smear) deficiency can result from dietary lack, impaired absorption, increased requirement, chronic blood loss

Question 44

aplastic anemia major etiologies

Answer 44

extrinsic: immune-mediated suppression of marrow progenitors intrinsic: abnormality of stem cells