Clin Path 3 Unit 2

Where is the site of granulocyte production in adults vs. juveniles?

1. Adults = active bone marrow

2. Juveniles = extra medullary (spleen, liver, lymph nodes, etc)

What instances would extra medullary responses be seen in adults for granulocyte production?

Inflammatory responses

• Most prominent in spleen, includes liver + lymph nodes

What do granulocytes originate from? What is the subpopulation?

Pluripotent stem cells (granulocyte/monocyte stem cells)

• Subpopulation differentiates into neutrophils, eosinophils, and basophils

What is the difference between orderly production and disorderly production from the bone marrow? What is each indicative of? What is myeloproliferative disorders means?

1. Orderly production = relatively few immature to increasing numbers of mature cells

• Important to ID demand from bone marrow

2. Disorderly production = disproportionally high # of immature cells compared to mature cells

• Important to ID disease (myeloproliferative disorders = 1 or more of the cell line is uneven (WBCs, RBCs, platelets))

What is the order of orderly production in the bone marrow?

1. Myeloblast divides into 2 promyelocytes

2. Promyelocytes divide into 2 myelocytes

3. Myelocytes divide twice = 8 metamyelocytes

4. Metamyelocytes divide into either band cells, eosinophils, segmented neutrophils, or mature basophils

What factors induce proliferation of WBCs? What specific factors from the already stated factors achieve this process?

1. Cytokines

2. Growth factors

   • Colony stimulating factor (CSF) produced by mononuclear cells + interleukins stimulate release of cells from bone marrow

What defines neutrophil kinetics? How long do they circulate before being needed elsewhere?

• Time for production (myeloblast to segmented neutrophil) = 7 days normally

• Inflammatory state alters to 2-3 days

1. Circulation life = time in circulation until migration to tissue = 6-10 hours normally

2. Inflammation may decrease due to rapid rate of consumption by tissue (tissue needs for whatever purpose)

What is the definition of hematopoiesis? How are cells removed and replaced?

Hematopoiesis = formation of blood into cellular components

• Cells removed by phagocytosis + spleen

• Cells replaced by: bone marrow production = medullary sites + extra medullary sites = spleen, liver, lymph nodes

What are the 4 general rules of maturation seen in erythrocytes + granulocytes?

1. Cell decreases in size as it matures

2. Nucleoli lost (nucleoli indicative of dividing cells)

3. Condensation of nuclear chromatin

4. Cytoplasm becomes less basophilic

What is the most immature stage in the myeloid phase of grnulopoiesis?

Myeloblasts

What are the 3 types of cells of the granulocyte lineage?

1. Neutrophils

2. Eosinophils

3. Basophils

What are identifying factors for myeloblasts (cell size, nucleus, chromatin, cytoplasm)?

1. Cell size = large

2. Nucleus = round to oval, 1 or more prominent nucleoli

3. Chromatin = finely granular (wadded up hairnet)

4. Cytoplasm = small to moderate amount, more blue than monocyte

What are identifying factors for promyelocytes (cell size, nucleus, chromatin, cytoplasm)?

1. Cell size = same or larger than myeloblast

2. Nucelus = perinuclear clear zone ± nucleoli

3. Chromatin = fine chromatin

4. Cytoplasm = primary granules (pink/purple, azurophilic)

5. Only cell that breaks the rules of maturation

What are identifying factors for myelocytes (cell size, nucleus, chromatin, cytoplasm)?

1. Cell size = smaller than promyelocyte

2. Nucelus = round to slightly oval

3. Chromatin = slightly granular

4. Cytoplasm = moderate amount, blue, secondary granules (light pink)

What are identifying factors for metamyelocytes (cell size, nucleus, chromatin, cytoplasm)?

1. Cell size = smaller than myelocyte

2. Nucelus = kidney-shaped (indented)

3. Chromatin = moderately granular + more condensed

4. Cytoplasm = blue, secondary granules

What are identifying factors for banded neutrophils (cell size, nucleus, chromatin, cytoplasm)?

1. Cell size = round + smaller

2. Nucleus = horseshoe shaped

3. Chromatin = more condensed

4. Cytoplasm = moderate amount, light blue

What are identifying factors for segmented neutrophils (cell size, nucleus, chromatin, cytoplasm)?

1. Cell size = smaller

2. Nucelus = segmented

3. Chromatin = coarsely granular + clumped

4. Cytoplasm = moderate amount, faint blue to pink

What are some identifying factors for hyperhsegmented neutrophils? What do they indicate?

1. 6 or more lobes

2. Aged neutrophil normally removed from circulation (can be caused by increased levels of endogenous corticosteroids)

3. Often indicates B12/folate deficiency

How does development of eosinophils/basophils differ from the myelocytic stage?

1. Secondary granules in myelocytic eosinophil = red to reddish orange

2. Secondary granules in myelocytic basophil = purple

3. Both slightly larger than segmented neutrophil