Lecture 22: Blood and Hematopoiesis Flashcards
Three functions of whole blood
- Transport
- Temperature regulation
- Water balance
Whole blood is what percent total body weight
5-10%
Whole blood is comprised of
60% of plasma (water, solutes)
40% formed elements (RBC, WBC, PLT)
Plasma composition
90% water
8% proteins
2% other solutes
Plasma is found.., unlike serum
in vasculature
Serum lacks…, unlike plasma
coagulation proteins (fibrinogen)
Plasma tubes
anticoagulant tubes - blood does not clot
Serum tubes
serum separators - blood is allowed to clot
Examples of plasma tubes
EDTA - purple
Heparin - green
Citrate - blue
Examples of serum tubes
Red top
Marble top
Daily output of RBC
2.5 billion
Daily output of WBC
1.0 billion
Daily output of PLT
2.5 billion
Most numerous formed element in blood
RBC (measured in millions, versus WBC and PLT measured in thousands)
Two functions of RBC
- Carry O2 to tissue and CO2 to lungs
- Involved in acid-base homeostasis
Shape of erthrocytes
- Biconcave disc
- Flexible membrane
- High SA-V ration
Mean cell volume is measured in
femtoliters (fL)
Lifespan of RBC is roughly proportional to
body size
Polychromatophils
- RBCs that are 1 stage back in development
- Normal finding in low numbers in some species
- Larger than mature RBC, smaller than neutrophil
- Round to amorphous
- Amphophilic color
Nucleated erythrocytes in mammals
- Abnormal finding associated with pathology
- Ex: Regenerative anemia, bone marrow damage, diseases affecting RBC maturation, damage to spleen/asplenia, some toxins
Least numerous formed element in the blood
Leukocytes
Function of leukocytes
Inflammation and the immune response
Two major categories of leukocytes based on developmental process
- Myeloid
2. Lymphoid
Four myeloid leukocytes
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
Lymphoid leukocytes
lymphocytes
Most numerous WBC
neutrophil
Function of neutrophils
- Innate immunity
- Phagocytic and killing cells
- Granules contain antibacterial substances
Neutrophil staining
- Nucleus: segmented with dense violet chromatin
- Cytoplasm: pale-staining, neutral
Heterophil staining
- Nucleus: segmented with dense violet chromatin
- Cytoplasm: red, rice-shaped granules
Band neutrophils
- Rare bands are normal blood smear findings in some species
- One stage less than mature segmented neutrophil
Band neutrophil staining
-Nucleus lacks clear segmentation and the irregular outline seen in mature neutrophil
Monocytes differentiate into
macrophages in tissue
Functions of monocytes
- Phagocytosis
- Antigen presentation to T-lymphocytes
- Iron storage and recycling
Mononuclear Phagocytic System (MPS) is comprised of
- Circulating monocytes
2. Tissue macrophages
Where is the MPS located
- Serosal cavities
- Liver: Kupffer cells
- Spleen
- Lungs (aalveolar macrophages)
- Brain (microglial cells)
- Bone (osteoclasts)
Monocyte size
Typically large cells, usually the largest in the blood smear
Nucleus of monocyte
- Shape ranges from round to kidney-shaped to band-shaped to psuedosegmented
- Chromatin is lacy/loosely clumped and magenta
Cytoplasm of monocyte
Abundant, blue, frequently vacuolated
____ eosinophils in tissue for each one in blood
300
Purpose of eosinophils
Modulate delayed and immediate typer hypersensitivity reactions
Eosinophils are attracted by
histamine
Eosinophils are commonly associated with
mast cells
Eosinophils are a defense against
helminthic parasites
Morphology of eosinophils
- Contain eosinophilic granules
- Bright reddish-orange, sometimes refractile
- Contain many arginine-rich proteins (anti-parasitic and anti-bacterial)
Nucleus of eosinophils
Segmented with clumped chromatin, similar to a neutrophil
Cytoplasm of eosinophils
Usually stains pale, contains eosinophilic granules
Least numerous WBC in blood
Basophils
Increased concentration of basophils are often associated with
parasitic infestations and allergic reactions
heartworm disease
Morphology of basophils
- Generally slightly larger than a neutrophil
- Basophilis granules contain histamine and many other proteins
Nucleus of basophils
Elongated and ribbon-like, segmented
Cytoplasm of basophils
Abundant amphophilic cytoplasm with purple granules
Second most numerous cell population in blood
Lymphocytes
Percentage of lymphocytes
20-40%
Lymphocytes are found
In blood, lymphatic circulation, lymphatic tissue
Purpose of lymphocytes
Humoral immunity: B cells, plasma cells
Cell-mediated immunity: T cells
Nucleus vs cytoplasm in lymphocyte
High N:C ratio, mostly nucleus
“Reactive” lymphocytes are associated with
An immune response
Plasma cells are..
Are they seen in normal blood smears?
- Fully differentiated B-cells
- Not normally seen in blood smears
Second most numerous formed element in the blood
Platelets/thrombocytes
Function of PLT
- Primary hemostasis (clotting)
- Role in primary inflammatory response
Do PLT have a nucleus?
Nope
“Activated” spread pseudopodia (star-shaped) occurs in the platelets of what species?
Feline
Three types of Romanowsky’s stains
- Wright’s
- Wright’s Giemsa
- May-Grimwald
Romanowsky Stains are able to differentiate between
Blood cells (RBC, WBC, PLT)
Two standard dyes used in combo in Wright’s Stain
- Eosin
- Methylene blue
Wright’s stain in vet med
Diff-Quik
Quick-Dip
Three dyes used in Wright’s-Giemsa stain
- Eosin
- Methylene blue
- Azure B
May-Grimwald
More intense coloration
New methylene blue is attracted to
Acidic/negatively charged proteins, DNA, RNA
Bone marrow is derived from
mesenchymal tissue
Red marrow purpose
- Produces all blood cells (hematopoietic tissue)
- Stores iron
Yellow marrow
- Fatty tissue that replaces red marrow
- Aging change
Bone marrow is high or low cellular tissue
high
The complex microenvironment of bone marrow supports the growth of
Hematopoietic cells
4 components of bone marrow
- Sinusoids
- Stromal cells
- Stem cells and precursor cells
- Macrophages
Sinusoids in bone marrow
- Large lumen
- Formed by discontinuous endothelial cells
Stroma
A CT network
Purpose of stroma in bone marrow
support structure of bone marrow
Stroma is composed of
- Mesenchymal cells
- Reticular cells
- Reticular fibers
Cells that live in bone marrow
- Hematopoietic stem cells
- Stem cells of each lineage
Purpose of bone marrow macrophages
- Store iron
- Involved in moderating hematopoiesis
- Regulates bone formation
Bone marrow cellularity varies with
age
Hematopoiesis
Process were specialized cellular precursors develop into highly differentiated cells of peripheral blood
Postnatal sites of hematopoiesis
- Bone marrow
- Proximal end of femur and humerus
- Pelvis
- Sternum
- Ribs
- Vertebrae
- Scapula
- Skull - Liver
- Spleen
Where does granulopoiesis occur
bone marrow
Granulopoiesis is regulated by
Colon stimulating factors and inflammatory cytokines