Thrombopoiesis Flashcards
CFU-GEMM → CFU-Meg →
Megakaryoblast → Megakaryocyte → Thrombocyte (platelets)
Thrombopoiesis / megakaryoctyopiesis is stimulated by
Thrombopoeitin
Between Megakaryoblast and megakaryocte
promegakarycote
As megakaryocytic cell matures…
Cell volume increases (different than any other cell line) - till fragmented
NC ratio decreases
Chromatin - condenses
Nucleoli - disappear
Undergoes endomitosis → nuclear material continuously doubles without dividing, resulting in polyploid nucleus
Megakaryoblast
Cytoplasm: pseudopodia present (ONLY class with these ) + non granular
Promegakaryocyte
Cytoplasm → pseudopodia + fine azurophilic granules
promegakaryocyte
Megakaryocyte (w/ platelets)
megakaryocyte (w/o platelets)
Megakaryocyte
size
Nucleus
Cytoplasm
NC
BM
size → 30-100 micro m
Nucleus → central and +2 lobules. blue/purple. granular, no nucleoli
Cytoplasm → pale/blue pink. Numerous azurophilic granules
NC → 1:1 - 1:2
BM
PLTs breaking off
metamegakaryocyte
platelet/thrombocyte
thrombocyte / platelet
thrombocyte/platelet
thrombocyte/platelet
size
Nucleus
Cytoplasm
granulomere
size → 1-4 micro m
Nucleus → none
Cytoplasm → light blue. reddish-blue granules
granulomere → central portion / red granules
hyalomere
pale portion/ the clearing area/ not refractive of a platelet/ thrombocyte
Platelets form _______ _____ between each other in megakaryocyte
demarcation membranes
30% of platelets sequestered in ___ as reserve
spleen
aged or dead platelets are removed by ___ and ___; similar system as RBC
spleen and liver
platelets are individual ___ ____ released into peripheral blood
cytoplasmic fragment
platelets circulate
9-12 days
platelets contain chemicals that function to:
- maintain blood volume integrity
- initiate homeostasis
- promote coagulation - provide a template to grow clot on and initiating other clotting factors
when vessel or tissue is damaged, the platelets
change shape, become clumpy and sticky (primary homeostasis)
osteoclasts
(separated nuclei)
Osteoclasts (macrophage in bone)
size
Nucleus
Function
NC
BM
size: >100 micro m
Nucleus - 2-50 separated nuclei with visible nucleoli
Function → absorption of bone
NC
BM