Hematology - Hematopoiesis, Erythropoiesis, & Stains Flashcards
What is a Romanowsky stain?
a nonvital (dead cell) polychrome stain
List the 4 Romanowsky stains.
GWML
- Giemsa stain
- Wright and Wright-Giemsa stain
- May-Grunwald stain
- Leishman stain
List the components of a Wright stain.
- methylene blue - a basic dye that stains acidic cellular components BLUE (DNA and RNA)
- eosin - an acidic dye that stains basic components red-orange (hemoglobin and eosinophilic cytoplasmic granules)
- methanol fixative - fixes cells to slide
- phosphate buffer (6.4)
What is Prussian blue?
a nonvital monochrome stain - stains specific cellular components
Lis the components of a Prussian blue stain.
- potassium ferrocyanide
- HCL
- safranin counterstain
What is Prussian blue used to visualize?
IHU
- iron granules in RBCs (siderotic iron granules)
- histiocytes
- urine epithelial cells
List the supravital (living cell) monochrome stains.
- new methylene blue
- neutral red with brilliant cresyl green as a counter stain
What is new methylene blue used for?
to precipitate RNA in reticulocytes => measure of bone marrow erythropoeisis
What is neutral red/brilliant cresyl green used for?
visualize Heinz bodies => G6PD deficiency and other unstable hemoglobin disorders
Are fixatives used in supravital stains?
no
Where does hematopoiesis occur in the fetus?
1-2 mo: yolk sac (primitive erythroblasts; embryonic hgb - Gower I, Gower II, & Portland)
3-6 mo: liver spleen (liver is primary site)
7 mo - 4 yr: bone marrow (ALL marrow is active)
List the organs of the reticuloendothelial system (RES).
- bone marrow
- spleen
- liver
- thymus
- lymph nodes
List the functions of the reticuloendothelial system.
- hematopoiesis
- phagocytosis
- immune defense
List the location of active marrow in adults.
flat bones
- skull
- sternum
- pelvis
- ribs
- vertebrae
Which hormone regulates the rate of erythropoiesis?
Erythropoietin (EPO)
Explain blood cell maturation.
Where and when is EPO produced?
-produced by the kidneys in response to cellular hypoxia and stimulates stem cells in the bone marrow, primarily CFU-E, to mature into erythrocytes
Which cells are derived from a common myeloid progenitor (CMP) cell in the bone marrow?
-erythrocytes
-granulocytes
-monocytes
-thrombocytes (platelets)
What is the precursor of the platelet?
megakaryocyte
-platelets are fragments of megakaryocyte cytoplasm
Where are lymphocytes produced?
- primary lymphoid tissue (thymus and bone marrow)
- spleen
- lymph nodes
- intestine-assoc. lymphoid tissue
- tonsils
What is the normal lifespan of an erythrocyte?
120 days
-phagocytic cells of the RES removed aged RBCs from circulation
-iron and globin chains are recycled
-heme is degraded and excreted as bilirubin
In a normal individual, what % of RBCs is replaced daily?
1%
-reticulocytes are released from the bone marrow into the circulation to replace aged cells removed by the RES
In the primary lymphoid tissue, what is the site of pre-B cell differentiation?
bone marrow
In the primary lymphoid tissue, what is the site of pre-T cell differentiation?
thymus
What is antigen-independent lymphopoiesis?
pre-B and pre-T cell differentiation in the primary lymphoid tissues
What is antigen-dependent lymphopoiesis?
lymphopoiesis that depends on antigenic stimulation of T and B lymphocytes
-occurs in secondary lymphoid tissue - lymph nodes, spleen, gut-associated tissue (Peyer’s patches)
What happens to the nuclear:cytoplasmic (N:C) ratio as most cells mature?
the ratio decreases as the volume of the nucleus decreases
What is the best indicator of the age of a cell?
that amount of chromatin clumping in the nucleus
What is the color of the cytoplasm in blasts?
royal blue due to the presence of RNA
What is the significance of nucleoli in a cell nucleus?
they are sites of ribosomal RNA synthesis
-seen in the nuclei of immature cells and reactive lymphocytes
-indicate that the cell is capable of mitosis
How are leukocytes classified?
- phagocytes (granulocytes, monocytes)
- immunocytes (lymphocytes, plasma cells, monocytes)
List the granulocytes.
- neutrophils
- basophils
- eosinophils
What leukocyte is the first to reach the tissues and phagocytize bacteria?
neutrophils
Which leukocyte arrives at the site of inflammation after neutrophils?
macrophages (monocytes in tissues)
What type of immunity do T lymphocytes provide?
cellular immunity
What lymphocyte makes up 80% of lymphocytes in the blood?
T lymphocytes
When activated, what to T lymphocytes produce?
cytokines/interleukins
What do B lymphocytes develop into in the tissue?
plasma cells
What do B lymphocytes produce?
antibodies
What type of immunity do B lymphocytes provide?
humoral immunity
What is the function of natural killer (NK) lymphocytes?
destroy tumor cells and cells infected with viruses
-also known as large granular lymphocytes (LGLs)
What is the function of eosinophils?
modulate allergic response caused by basophil degranulation
What is the function of basophils?
mediate immediate hypersensitivity reactions (type I, anaphylactic)
Name the stages of development in the erythrocytic series, using 2 systems of nomenclature.
- rubriblast (pronormoblast)
- prorubricyte (basophilic normoblast)
- rubricyte (polychromatophilic normoblast)
- metarubricyte (orthochromic normoblast)
- diffusely basophilic erythrocyte (polychromatophilic erythrocyte/reticulocyte)
- mature erythrocyte
Pronormoblast
14-24 um
N:C ratio is 8:1
royal blue cytoplasm
fine chromatin
1-2 nucleoli
normally confined to the bone marrow
-14-24 um
-N:C ratio is 8:1
-royal blue cytoplasm
-fine chromatin
-1-2 nucleioli
-normally confined to the bone marrow
Pronormoblast
Basophilic normoblast
12-17 um
N:C ratio of 6:1
deep blue cytoplasm
chromatin is coarser with slightly visible parachromatin
nucleoli usually not visible
normally confined to the bone marrow
-12-17 um
-N:C ratio of 6:1
-deep blue cytoplasm
-chromatin is coarser with slightly visible parachromatin
-nucleoli usually not visible
-normally confined to the bone marrow
basophilic normoblast
polychromatophilic normoblast
10-15 um
N:C ratio is 4:1
cytoplasm is polychromatophilic due to hemoglobin production
chromatin is clumped with distinct areas of parachromatin (spoke-like pattern)
last stage to divide
normally confined to the bone marrow
-10-15 um
-N:C ratio is 4:1
-cytoplasm is polychromatophilic due to hemoglobin production
-chromatin is clumped with distinct areas of parachromatin (spoke-like pattern)
-last stage to divide
normally confined to the bone marrow
polychromatophilic normoblast
Orthochromic normoblast
-8-12 um
-N:C ratio is 1:2
-nucleus is pyknotic
-last nucleated stage
-normally confined to the bone marrow
-8-12 um
-N:C ratio is 1:2
-nucleus is pyknotic
-last nucleated stage
-normally confined to the bone marrow
orthochromic normoblast
polychromatophilic erythrocyte
-7-10 um
-no nucleus
-cytoplasm is diffusely basophilic (bluish tinge)
-reticulum seen with supravital stain
-0.5-1.5% of RBCs in adult peripheral blood
-7-10 um
-no nucleus
-cytoplasm is diffusely basophilic (bluish tinge)
-reticulum seen with supravital stain
-0.5-1.5% of RBCs in adult peripheral blood
polychromatophilic erythrocyte
mature erythrocyte
-7-8 um
-biconcave disk
-reddish-pink cytoplasm with area of central pallor 1/3 diameter of cell
-7-8 um
-biconcave disk
-reddish-pink cytoplasm with area of central pallor 1/3 diameter of cell
mature erythrocyte
What is the last nucleated stage in the development of an erythrocyte?
orthochromic normoblast (metarubricyte)
What is asynchronous erythropoiesis?
the nucleus and cytoplasm mature at different rates
What causes megaloblastic asynchronous erythropoiesis?
vitamin B12 and/or folic acid deficiency
Explain megaloblastic asynchronous erythropoiesis.
-nucleus lags behind cytoplasm in maturation
-cells grow larger without dividing
What characteristics of megaloblastic asynchronous erythropoiesis are seen on the peripheral smear?
oval macrocytes
What causes iron deficiency asynchronous erythropoeisis?
iron deficiency - reduces erythropoietin production
Explain iron deficiency asynchronous erythropoiesis.
-cytoplasm lags behind nucleus in maturation due to inadequate iron for hemoglobin synthesis
What characteristic is seen on the peripheral smear in iron deficiency asynchronous erythropoiesis?
microcytic, hypochromic RBCs
What is the best way to judge the size of an erythrocyte on a Wright-stained smear?
a normocytic RBC is approx. the same size, or slightly smaller than the nucleus of a mature lymphocyte
What is the first sign of accelerated erythropoiesis?
increased reticulocyte count
What substances are needed for erythropoiesis?
- iron
- amino acids
- folic acid/B12
- erythropoietin
- vitamin B6
- trace minerals
Why is iron needed for erythropoiesis?
transports oxygen
(ferrous state - Fe2+)
Why are amino acids needed for erythropoiesis?
globin-chain synthesis
Why are folic acid and B12 needed for erythropoiesis?
DNA replication/cell division
How does the size of a cell change during maturation?
becomes smaller
How does the N:C ratio of a cell change during maturation?
becomes smaller
How does the cytoplasm of a cell change during maturation?
-less basophilic due to loss of RNA
-granulocytes produce granules
-erythrocytes become pink due to hemoglobin production
How does the nucleus of a cell change during maturation?
-becomes smaller
-nuclear chromatin condenses
-nucleoli disappear
-in granulocyte series = nucleus indents, then segments
-in erythrocyte series = nucleus is extruded
