Fundamental Hematology Principles & Hematopoiesis

Whole Blood Includes…?

Erythrocytes, leukocytes, platelets, and plasma

Buffy Coat

Small white layer btn RBCs & plasma

• Appears when specimen is centrifuged

• Leukocytes and platelets

Plasma

Liquid portion of unclotted blood OR component produced when blood contains anticoagulant

Serum

fluid remaining after coagulation and a clot has formed

Plasma vs Serum

contains all coags factors vs lacking fibrinogen group coag proteins

Homeostasis

the process that maintains stable internal conditions in the body, including blood clotting and fluid balance.

Normal Osmotic Concentration

Termed Isotonic, meaning the osmotic pressure is balanced with that of the cells, preventing net movement of water.

Hypotonic Solution

• ↑ H2O, ↓ Solute conc.

• Cells swell → lyse

Hypertonic Solution

• ↓ H2O, ↑ Solute conc.

• Cells crenate

pH reference range: venous vs. arterial blood

• venous: 7.36-7.41

• arterial: 7.38-7.44

Body Temp Normal Range

37°C (97-99°F)

MCV (mean corpuscular volume) range, definition, and importance

• 80-100 fL

• avg. vol. of RBC

• ↑ = megaloblastic anemia, hemolytic anemia, liver disease, norm newborn

• ↓ = iron defic. anemia, thalessemia, sideroblastic aneia, lead poisoning

MCH (mean corpuscular HgB) range, definition, and importance

• 26-34 pg

• avg. weight of HgB in RBC

• ↑ = macroytic anemia

• ↓ = microcytic, hyperchromic anemia

MCHC (mean corpuscular HgB conc.) range, definition, and importance

• 32-37 g/dL

• avg. conc of HgB in RBC

• ↑ = error or presence of spherocytes

• ↓ = hypochromic RBCs → iron defic. and thalessemia

MCH (pg) formula

Hgb (g/dL) x 10 / RBC count ( x 10^12/L)

MCV (fL) formula

HCT (%) x 10 / RBC count (x 10^12/L)

MCHC (g/dL) formula

Hgb (g/dL) x 100 / Hct (%)

RBC indicies triangle

Hgb (Hemoglobin) Reference Range

Males: 13.5-17.5 g/dL

Females: 12.0-16.0 g/dL

Platelets Referene Range

150 - 450 × 10^9/L (150,000-450,000/uL)

MPV (mean platelet volume)

6.8 - 10.2 fL

*Note: MPV is analagous to MCV for RBCs

Relative vs Absolute Count

Proportion of a cell type in WBC count % vs. actual cells per blood volume #.

Relative Lymphocytosis

inc. in % of lymphocytes, associated w/ neutropenia

Absolute Lymphocytosis

inc. in # of lymphocytes

Relative vs Absolute polycythemia

increase in RBCs, distinguishing between % and actual # of cells.

Nonvital (dead cell) polychrome (Romanowsky)

• Most common: Wright stain

• Contains Methylene blue: basic dye that stains acidic (DNA and RNA) blue

• Contains Eosin: acidic dye that stains basic (Hgb and eosinophilic cytoplasmic granules) red-orange

• Methanol Fixative

• Phosphate Buffer: 6.4-6.8

Causes of RBCs too red and WBC nuclei poorly stains

< 6.4 pH, excess buffer, dec. staining time, inc. washing time, thin, expired stains

RBCs and WBC nuclei poorly stained

> pH 6.8, too little buffer, inc. staining time, poor washing, thick smear, inc. protein, heparinized blood sample

Nonvital Monochrome Stain

Ex: Prussian blue stain, used to identify iron granules

Supravital Monochrome Stain

• New methylene blue: stains RNA in reticulocytes

  • Measure level of erythropoiesis

• Neutral red w/ brilliant cresyl green: visualize heinz bodies

  • shows G6PD deficiency, unstable HgB

Hematopoesis

Production and differentiation of blood cells in the bone marrow.

Reticuloendothelial System (RES)

Blood cell production, maturation, and death occur in the organs

• includes: BM, spleen, liver, thymus, lymph nodes

RES functions in…?

Hematopoiesis, phagocytosis, and immune defense

Intrauterine Hematopoiesis includes three phases

• Mesoblastic (yolk sac):

  • primitive nucleated erythroblast → primitive nucleated erythroblast → Hgb: portland, Gower I-II

• Hepatic (liver) phase:

  • RBCs production → Hgb F

• Myeloid/Medullary:

  • BM produces granulocytes → HgbF (HgbA after 6 months)

• Red marrow → yellow marrow

Bone Marrow Cellularity

Ratio of marrow cells to fat (hematopoetic cells)

1. Normocellular: 30-70%

2. Hypercellular/Hyperplastic: >70%

3. Hypocellular/Hypoplastic: <30%

4. Aplastic: Little to none

Pluripotential Stem Cells

develop into committed progenitor cells (lymphoid or myeloid)

Lymphoid Cells

B or T lymphocytes

Myeloid cells

CFU-GEMM → differentiates into different committed progenitor cells → mature blood cells

Primary vs. Secondary Lymphoid Tissue

Antigen-INDEPENDENT vs. Antigen-DEPENDENT

Primary Lymphoid Tissue

1. BM: site of pre-B cell differentiation

2. Thymus: site of T cell differentiation

Secondary Lymphoid Tissue

1. B and T lymphs enter blood

2. Includes lymph nodes, spleen, gut-associated (peyer’s patch)

Phagocytes vs Immunocytes

Granulocytes, monocytes vs. lymphocytes, plasma cells, and monocytes

WBC ref. range

4.0 - 11.0 x 10^9 cells/L (10³ /uL)

Granulocyte

Neutrophils, PMNs, Seg Eos, & Basos

Neutrophils

1st to Phagocytize, destroy bacteria

Monocytes

differentiate into macrophages, phagocytize foreign bodies

T Lymphocytes

provide cellular immunity, produce cytokines/interleukins

B Lymphocytes

develop into plasma cells, produce antibodies, needed for humoral immunity

NK cells

natural killer cells, large granular lymphocytes

Eosinophils

mediate allergic response, caused by basophil degranulation and combat parasitic infections by releasing cytotoxic granules.

Basophils

mediate intermediate hypersensitivity rxns (type I, anaphylactic)

Lymphoid, Pan T Cells CD Marker

CD2, CD3

Helper/Inducer T Cells CD Marker

CD4

Suppressor/Cytotoxic T Cells CD Marker

CD8

Pan Myeloid CD Marker

CD13

Monocytes CD Markers

CD11c, CD14

Lymphoid, pan B cells CD Marker

CD19, CD20

Pan Myeloid CD Marker

CD33

Stem cell marker (lymphoid and myeloid precursor) CD Marker

CD34

NK Cells CD Marker

CD16, CD56

Medullar hematopoiesis

Within BM, 5th month of gestation

Extramedullary hematopoiesis

Outside BM

• occurs when BM cannot meet body requirements

• occurs mainly in the liver and spleen, hepatomegaly and/or splenomegaly

Nucleus

• Chromatin: composed of DNA and proteins

• Nucleoli: RNA

Cytoplasm

• Golgi complex

• Lysosomes

• Ribosomes

• Mitochondria

• Endoplasmic reticulum

General Cell IMMATURE CELLS Maturation Characteristics

• Cell is large

• Nucleoli Present

• Chromatin Fine and Delicate

• Nucleus Round

• Cytoplasm dark blue (rich in RNA)

• High N:C ratio

General Cell MATURE CELLS Maturation Characteristics

• Cell is smaller

• Nucleoli absent

• Chromatin coarse and clumped

• Nucleus round, lobulated, or segmented

• Cytoplasm pale blue (less RNA)

• Low N:C ratio