Unit 1: Review of Normal Blood Cell Maturation Flashcards
Leukopoiesis
is the production and proliferation of white blood cells,
with the exception of lymphocytes, in the bone marrow, lymph
nodes, & thymus.
Myelopoiesis (granulocytopoiesis)
refers to the production of
neutrophils, eosinophils, and basophils
Lymphopoiesis
refers to the production of lymphocytes
There are 5 main types of WBCs (in order of their predominance in
the N. adult)
-Neutrophils (Segs) 50-70%
* Lymphocytes (Lymphs) 18-42%
* Monocytes (Monos) 2-11%
* Eosinophils (Eos) 1-3%
* Basophils (Basos) 0-2%
Granulocytes
(develop only in bone marrow)
Includes: Segs, Eos, Basos, and Monos
Lymphocytes or Mononuclears
(develop in the bone marrow
and lymphoid tissue)
Includes: Lymphs, and NK cells
Mononuclears
Mononuclears can have very fine granules; it’s just that they are not
granulocytes, which all have large, noticeable granules & segmented
nuclei.
As defense against foreign (“non-self”) invaders via
- Ab production by immunocytes (i.e., lymphs.)
- Cytokine production by lymphocytes (aka.
lymphokines.) - Inflammatory mediator production by segs &
monos. - Phagocytosis (i.e., granulocytes and mononuclear
cells)
As a normal cell matures
* Overall:
- cell size decreases
- nuclear chromatin pattern becomes denser
- nucleoli disappear
- amount and color of cytoplasm changes
- size of nucleus decreases greater than the size of the cell (N:C ratio)
Cytoplasmic Maturation
- deep blue color (high RNA content) pales
- granules may appear
- amount increases
Nuclear Maturation:
-nucleus decreases in size (exits entirely in RBCs!)
* chromatin becomes more condensed or clumped
* color changes from reddish to bluish-purple
* nucleoli may decrease in # or become absent
Erythron
the collection of all stages of erythrocytes throughout the body
Hypoxia
diminished availability of oxygen to the body tissues
* Occurs when the oxygen tension in the cells is decreased
The role of RBCs is to
Carry oxygen
Erythropoietin Production and Regulation
EPO is produced primarily in the kidney in response to - Degree of blood oxygenation
it functions to maintain normal RBC mass
Erythropoietin
Initiates a cascade of events that lead to increased RBCs in circulation
- Allows early release of reticulocytes
- Increases number of mature erythrocytes
- Reduces marrow transit time
Pronormoblast (Rubriblast or Proerythroblast) - “Blast”
Cell size
N:C ratio
nucleus shape
Note
- Cell size: 12-20 μm
- Nucleus: contains nucleoli & fine chromatin;
round to slightly oval shape.
High N:C ratio (8:1) - Cytoplasm: very basophilic (high RNA content, lots of organelles),
with the lighter-staining perinuclear area around Golgi (not always visible)
Note: BFU-E for 1 week » CFU-E for 1 week » Pronormoblast for ~24 hrs.
Basophilic Normoblast
Cell size
Nucleus:
N:C ratio
Cytoplasm-
(Prorubricyte /Erythroblast)
- Cell size: 10-15 μm
- Nucleus: round, coarser chromatin; no visible
nucleoli
N:C ratio decreasing to 6:1
- Cytoplasm: temporarily even more basophilic (royal
blue); Golgi may be visible as light area near nucleus.
Polychromatic normoblast
(Rubricyte/Polychromatic
erythroblast)
- Cell size: 10-12 μm
- Nucleus: round, sometimes eccentric, smaller, with
coarser chromatin
N:C ratio of 4:1 - Cytoplasm: opaque, violet-blue or grayish color (due to
Hgb synthesis) polychromasia - (NOTE: Last stage capable of mitosis.)
Orthochromic normoblast
- (Metarubricyte/Orthochromic
erythroblast) - Cell size: 8-10 μm
- Nucleus: pyknotic (degenerated nuclear chromatin);
eventually extruded
N: C ratio of 1:2 - Cytoplasm: polychromasia
- NOTE: This stage is typically called a “nucleated red”, & the WBC count must be corrected if 5 or
more of these are present on a 100 cell WBC differential, because automated analyzers mistake
them for white blood cells!
Erythroblasts (NRBC) stain
Wright-Giemsa Stain
- Reticulocyte - “Retic“
- Cell size: 7-9 μm (nearly normal!)
- Nucleus: none present
- Cytoplasm: varying degrees of polychromasia
(variation in cytoplasmic color, usually a
bluish tinge; may still have basophilic stippling.
Reticulocyte - “Retic
Resides in marrow for
1 day, then peripheral blood for 1 day, then retained in the spleen for
pitting and polishing for a few days, then released as a mature cell
RETICULOCYTE
(Retic)
Normal ranges:
Adults 0.5 - 2.0 %
Children 1.0 - 3.0 %
Newborns 2.0 - 6.0 %
New Methylene Blue
Retic Stain
Erythrocyte
- Cell size: 7 - 8 μm
- Nucleus: none present
- Cytoplasm: has distinctive central pallor; no protein
or Hgb made; no mitochondria present
Erythrocyte
Lifespan ? = __________
Travels how far in that time? = __________120 day
120 days
300 miles
Neutrophilic Maturation
CFU-S, or hematopoietic stem cell (HSC)
-Cluster of Differentiation (CD) 34 antigen
* Undergoes stimulation, mitosis, and maturation in a stem cell (CFU-GEMM)
that’s specific for myeloid cells
Neutrophilic Maturation
CFU-GEMM
- CD34 and CD33 antigens
- Matures into CFU-GM
Neutrophilic Maturation
CFU-GM
- ILs and CSFs control the stability of cell numbers and their functions
- Matures into a myeloblast
Colony Stimulating Factors
Multi-CSF
Sources and functions
(i.e., IL-3) production is stimulated by
endotoxin released from infection
* Source – secreted by marrow fibroblasts, T-lymphs,
macrophages, and monocytes
* Function – stimulates regeneration, maturation, and
differentiation of multipotential and unipotential stem cells
Colony Stimulating Factors
GM-CSF
Sources and functions
is important for myeloid maturation in the
marrow
* Source – secreted by T-lymphs, marrow fibroblasts,
marrow endothelial cells and monocytes
* Function – stimulates neutrophils, eosinophils, and
monocyte growth
Colony Stimulating Factors (cont.)
G-CSF
Sources and functions
is a more specific granulocyte growth factor
* Source – monocytes, marrow fibroblasts and endothelial
cells
* Function – stimulates neutrophils, and enhances functional
response of neutrophils
Colony Stimulating Factors (cont.)
M-CSF
Sources and functions
(i.e., CSF-1) is the primary monocytic growth
factor
* Source – secreted by mature monocytes, marrow
fibroblasts, and marrow endothelial cells
* Function – stimulates macrophages and the release of G-
CSF from monocytes. Stimulates the release of tumor
necrosis factor (TNF), interferon, and IL-1 from
macrophages
Myeloblast: “-blast”
cytoplasm
dark blue to blue cytoplasm
Myeloblast: “-blast”
what may begin to appear
Primary granules may begin to appear
Myeloblast: “-blast”
Chromatin
lacy, smooth, delicate, & uniformly distributed chromatin
Myeloblast: “-blast”
_____ distinct nucleoli
1-2 distinct nucleoli
Myeloblast: “-blast”
Cell size
A large cell (15-20 μm)
Myeloblast: “-blast”
N:C ratio
- high N:C ratio of 4:1 (so not much cytoplasm)
Myeloblast: “-blast”
_________ normal in bone marrow (none are normal in peripheral blood
(p.b.)
1-2% normal in bone marrow (none are normal in peripheral blood
(p.b.)
Myeloblast: “-blast”
Express antigens
CD13 and CD33
Myeloblast: “-blast”
Using light microscopy, it’s hard for
non-experts to differentiate myeloblasts/monoblasts / lymphoblasts
Promyelocyte: “Pro-”
large, prominent, reddish-purple _______
primary granules (described as
azurophilic)*
Promyelocyte: “Pro-”
dark blue to blue _______
cytoplasm
Promyelocyte: “Pro-”
uniformly distributed
chromatin
Promyelocyte: “Pro-”
N:C ratio of
3:1
Promyelocyte: “Pro-”
less distinct __________
nucleoli, but still may be present
Promyelocyte: “Pro-”
It may be larger than ________
blast form (approx. 20 μm)
Promyelocyte: “Pro-”
_________ % normal in bone marrow, none normal in p.b
Primary =
2-5%
Thus used to help distinguish blasts from pros.
(Primary = pro = red-purple)
- Myelocyte: “Myelo-”
Pinkish _________
pinkish secondary/specific granules now visible*; 1o granules less visible
“Specific = Secondary
- Myelocyte: “Myelo-”
Dawn of neutrophilia”
occurs: specific granules tend to form in Golgi area causing pink arc
- Myelocyte: “Myelo-
__________ losing blue color due to decreased RNA synthesis
cytoplasm losing blue color due to decreased RNA synthesis
- Myelocyte: “Myelo-”
nucleus more
condensed, with chromatin clumped; nucleus starting to “round up”
with one flatter side
- Myelocyte: “Myelo-”
N:C ratio of
2:1
- Myelocyte: “Myelo-”
_________ % normal in bone marrow, none normal in p.b.
<10% normal in bone marrow, none normal in p.b.
- Myelocyte: “Myelo-”
Myelocytes have greatest morphological variation of all the ______________
Neutrophils
Thus used to help tell pros from myelocytes!
Primary/Nonspecific or Azurophilic
Red-purple color= Become light blue as cell mature
mostly visible in (blast &) Start at myelocyte stage Appear very late stages
promyelocyte stages
Lysosomes; contains lysozyme, acid hydrolases, myeloperoxidase (MPO)*, proteases, & superoxide
Stain pos. for peroxidase
Secondary/Specific or Neutrophilic
Color: Pale lavender-pink
Start at myelocyte stage Cause “dawn of neutrophilia
Lysosomes; contain lysozyme, Lactoferrin**, collagenases, & complement activators
But no peroxidase
Tertiary granules
Color- Invisible on Wright’s stain)
blue-purple with
special LAP*** stain
Appear very late stages
Lysosomes; contain lysozyme, DAF, gelatinase, & LAP
NO peroxidase
Metamyelocyte: “Meta-”
kidney-bean or peanut-shaped ________
nucleus
Metamyelocyte: “Meta-”
nuclear chromatin
more coarsely clumped