Blood and Hematopoiesis Flashcards
Blood consists of
Formed elements (cells) and amorphous ground usbstance (serum)
Blood and fibers
Blood contains no fibers but upon injury, fibrinogen can form fibers
Blood develops from
Mesenchyme
Hematocrit and normal values
Percentage volume of blood by erythrocytes
Normal - 45%…lower=anemia
RBC appearance
Biconcave disc
Rouleaux formation forming columns
Reticulocytes and appearance
Immature RBCs…slightly basophilic from residual rRNA from hemoglobin synthesis (Howell Jolly bodies)
Basophilia lost after 2 days in circulation
1-2% of peripheral blood
Elevation in reticulocytes means
Increase in RBC production
Anemia
Decrease in blood concentration of hemoglobin due to reduced number of total RBCs or decrease in individual hemoglobin content
Platelets - origin and apperance
From megakaryocyte cytoplasm
Also called thrombocytes
Disc-like
Hyalomere outer zone of cytoskeleton (MTs_
Inner granulomere containing serotonin (vasoconstrictor) or other coagulation components
NO NUCLEUS
Granular leukocytes
Segmented nuclei and non-dividing terminal cells with life span of a few days…contain primary and secondary granules…include neutro, baso, and eosino
Agranular leukocytes
Nuclei are round or indented and contain only primary granules…lymphos and monos
Specific granules
Secondary granules
Found only in granulocytes and have specific functions in cell…characterized by staining properties
Azurophilic granules
Primary granules…function as lysosomes
Neutrophil appearance, lifespan, and function
Segmented (2-5 lobe) nucleus increasing with age
Basophilic nucleus
Can see drum-stick appendage or Barr body
Lots of neutrophilic granules and fewer azurophilic granules
Circulate 9-10 hours and enter connective tissue…live 1-2 days
Acute inflammation
Become PMLs after they leave blood
Band neutrophils
Immature neutrophils (1-2%)
Neutrohpilia could mean
Acute response to bacterial infection
Shift to the left
Increase in number of immature neutros leaving bone marrow and entering peripheral blood
Eosinophil appearance, function, lifespan
2 lobe nucleus
Specific granules exhibit crystalline core and similar to lysosomes
Circulate 1-10 hours
Allergic responses (ag/ab) and can clog kidneys
Eosinophilia indicates
Allergic reaction
Eosinophils produce
HIstaminase and aryl sulfatase B
Basophil appearance function and lifespan
Bi-lobed nucleus Granules with heparin and histamine Systemic allergic reactions and type 1 hypersensitivity reactions Found in phagocytic Large blue granules
Hematopoeisis
Blood cell formation
Hematopoietic tissues
Where hematopoiesis occurs
Begins in wall of yolk sac
By 6th week moves to liver where erythropoiesis is more pronounced than myelopoeisis
Post-natal sites are bone marrow, spleen, lymph nodes, and thymus
Erythropoiesis
In bone marrow producing RBCs
Lymphopoesis
Occurs in bone marrow and lymph tissue and makes lymphcytes
Myelopoesis
producing granulocytes, monocytes, and platelets in bone marrow
Bone marrow location
In medullary cavity of young long bones and space of spongy bone…replcaed by yellow throughout life…highly cellular connective tissue specialized for development of blood cells
Bone marrow functions
Initially - growth and remodeling of bone
Secondarily - hematopoetic
Bone marrow structure
Blood sinuses and spong-like network of hematopoetic cells that lie in cords between sinuses
BM components
Reticular conn tissue stroma
Hematopoietic cords
Venous sinuses
Reticular conn tissue stroma
Fromed from reticular cells and fibers (Type 3 collagen)…support developing blood cells and separate from endothelium…secrete CSF
Hematopoetic cords
Make up parenchyma…filled with blood cells of all type and stages…nests occupy different sites in marrow cords
Venous sinuses
THin walled vessels positioned between arteries and veins
How does new cell enter ciruclation?
Penetrate endothelium via diapedesis
Macrophages located
Close to venous sinuses
Myeloid and lymphoid stem cells are
Multipotential
CFUs
Erythroid, megakaryoctye, baso, eosino, and granulocyte-macrophage (monos and neutros_
What regulates hematopoiesis>
Glycoprotein hormones and stimulating factors
Erythropoetin
Controls RBC production
How are RBCs distinguished vs. others
RBCs on basis of color of cytoplasm
Others based on nucleus and granule color
Erythroid lineage
Basophilic erythroblast - deep blue because rRNA…from proerythroblast and can divide by mitosis
Polychromatophilic erythroblast - gray…last stage cells can dfivide
Orthochromatic erythroblast - pink
Reticulocyte - pink with small rRNA present…mature into RBCS after 1 day in circulation**
RBC - sac of hemoglobin
Myeloid lineage
Promyelocyte - ROund and foamy looking nucleus….only primary granule sythesis
Myleocyte - Slight indentation…starts to accumulate specific granules…last myeloid cell capable of mitosis
Metamyelocyte - markedly indented and post-mitotic
Band form - nucleus U shaped but not segmeneted
Mature cell- SEGS with segemented granules
Platelet formation
Undergo endoreduplication to cause multilobulated nucleus
sER is important
Strips of platelets (cytoplasmic segmenets of megakaryocytes) differentiate into individual platelets
