Platelets

platelet morphology

circular/elliptical shape

1. peripheral zone: allows for adhesion

2. sol-gel zone: cytoskeleton

3. organelle zone

4. membranous system

platelet peripheral zone anatomy

glycocalyx: external coating important for reacting with coagulation factors

plasma membrane

submembranous area

site of platelet synthesis

bone marrow

thrombopoietin function

hormone produced by kidneys (liver and spleen) that influences megakaryocyte size → # of platelets produced

platelet maturation sequence

megakaryoblast → megakaryocyte → platelet

platelets produced from one megakaryocyte

2000-4000

platelet lifespan

9-12 days

platelet turnover

body produces and destroys 35,000 platelets in 24 hours

platelet function

aid in primary hemostasis (blood clotting)

normal platelet count

150,000 - 450,000 × 10^9/L

why correlate automated and manual platelet estimates

internal quality control check; to ensure the analyzer is accurate

when should you repeat a platelet count

when abnormally high or low results are flagged

thrombocytosis

increase above the normal patient range in the number of circulating platelets

thrombocytopenia

decrease below the normal pt range in the number of circulating platelets

ploidy value

specified number of sets of chromosomes

megarkaryocyte maturation

1. nucleus becomes lobulated

2. then cytoplasm increases and becomes more granular

megarkaryocyte maturation duration

4-5 days in bone marrow

platelet nucleus

does not exist because platelets arise from the cytoplasm of megakaryocytes

DMS

demarcation membrane system

network of tubules in the cytoplasm of megakaryocyte that gives rise to individual platelets

platelet satellitsm

platelets encircling neutrophils due to a reaction with EDTA

how to report platelet count when platelet clumping occurs

must collect specimen in buffered sodium citrate tube

how to increase platelet production

1. increase number of megakaryocytes

2. increase size of megakaryocytes

3. decrease maturation time of megakaryocytes