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Bone Marrow and Leucocytes (1.18.1.15) - Coggle Diagram
Bone Marrow
and Leucocytes
(1.18.1.15)
Cellular components of the blood:
Erythrocytes
Platelets (thrombocytes)
Leucocytes (WBCs)
Granulocytes
Neutrophils
Eosinophils
Basophils
Agranulocytes
Lymphocytes
T cells (70-80%)
B cells (10-15%)
NK cells (5-10%)
Monocytes
WBCs in the Blood
Leucopenia
monocytopenia
eosinopenia
lymphopenia
neutropenia
Leucocytosis
Lymphocytosis
neutrophilia (neutrophilic leucocytosis)
monocytosis
basophilia
eosinophilia
basophilia
Romanowsky Stains
Eosin
acidic
stains basic tissue components orange
eosinophilic/acidophilic
orange
Azure
basic
stains acidic tissue components blue
basophilic
Blue
nucleus will stain blue
Leishman
used on blood smears
can distinguish certain protozoan parasites
Wright
Used on BM aspirates and blood smears
Giesma
Stains cytoplasm shades of pink
used on blood smears
Neutrophil
Appearance
sparse granules
granules in the cytoplasm stain NEUTRALLY
2 or more lobed nucleus often connected by thin strands of chromatin
10-12 microns
Circulate blood for minutes to 6-8 hrs
In tissues survive 1-2 days
5 x more in BM than blood
actively motile cells
Development of macrophages and microphages (neutrophils) influenced by GM-CSF
heterophils have the same function but granules stain red (are in rabbits, reptiles and birds)
Range of different size granules and larger lysosomes
Complement activators
acid hydrolases
myeloperoxidase
lysozyme
elastase/ collagenase/gelatinase
cathepsin
Activities
chemotaxis
phagocytosis and killing
oxygen-independent
sites of poor blood flow/abscesses
enzymes/pharmacological agents
lysozyme- hydrolyses glycopeptide coats of many bact.
cathepsin
hydrolytic enzymes
oxygen-dependent (respiratory burst)
Increased oxygen utilisation- generates reactive oxygen species
production of hyperchloric acid
Inflammation
selectin receptors- interact with selectins on endothelial cells
IL- 1 and TNF cause cells to release IntercellularAdhesionMolecule (ICAM)-1 and VascularCellAdhesionMolecule (VCAM)-1 which slows the passage of the neutrophil in the blood vessel so it can escape to gain access to the site of inflammation
In most abscesses dying neutrophils make up majority of pus
Development in Bone Marrow
Different stages of neutrophil
3-myelocyte
4-metamyelocyte
2-promyelocyte
5-band neutrophil
only appear in blood on acute inflammation
1-myeloblast
6-segmented neutrophil
Neutrophilia and left shift
Often occurs during infection
circulating neutrophil numbers increase
begin to see immature band neutrophils in the blood- leave BM early
Eosinophils
2 lobed nucleus, dense orange granules, blue cytoplasm
Strongly associated with allergy, parasites and fibrosis. These are rarely found in healthy blood.
Specific granules contain:
Major basic protein
Eosinophil cationic protein
Eosinophil peroxidase
Eosinophil-derived neurotoxin
Enzymes - histaminase and collagenase
Species variation:
Eosonophilic conditions:
Equine Idiopathic focal eosinophilic enteritis and diffuse eosinophilic enteritis
Intestinal eosinophil inflammation
Unknown cause and linked to surgical colic cases
Eosonophilic granuloma complex
Skin condition of cats
Underlying allergy
Resulting in swelling, lesions, plaques
Collagen released by cells contributes to swelling
Basophils
Appearance
lobed but not well defined
dense blue granules in cytoplasm
RARE in blood
Specific granules
heparin
histamine
leukotrienes
lysosomes
can be weakly phagocytic
surface IgE receptors
parasitic infection/ allergy
recruited into tissue
What is normal?
0-300/microlitres in blood
in blood- rabbits> ruminants and horses>cats and dogs
basopenia is fine
basophilia is sign of pathology/disease
Mast cells
Structure
Have IgE receptors on their surface
They are triggered when antigens bind to surface IgE, causing granule contents to be released
Particularly involved in the response to allergy and parasitic infections (worms)
Found in tissues, not blood
What occurs with them?
Rounded nuclei with granular cytoplasm
Granlused release: Histamine, Heparin, Proteases, Leukotrienes, Eosinophil, Neutrophil chemotatic factor, interleukins
Monocytes
Features:
Arise from same precursors as neutrophils
Present in blood but not tissue
Exit of blood into tissue or lymph node gives rise to macrophages and dendritic cells
Within tissues they take the form of many cells
Macrophages
Phagocytosis pathogens, foreign bodies, antigen
Communicate with T-cells
Dendritic Cells - primarily communicate with T-cells
Monocytes
arise from same precursor as neutrophils
present within blood not tissue
exit of blood inot tissue or lymph gives rise to more macrophages and dendritic cells
dendritic cells
Primarily communicate with T-cells
macrophages
phagocytosis pathogens, FB and antigen
communicate with T-cells
lymphocytes
B lymphocytes
develop in bone marrow of some species or intestine of others (eg sheep)
T lymphocytes
Develop in bone marrow
always enter thymus for 'education'
cant tell between B and T on a smear, typical and reactive forms are seen
