Platelets (Exam 1) Flashcards
How large or small are platelets?
smaller than RBC ~3-4 um
What is another word for platelets?
thrombocytes
What is thrombocytopenia?
decreased number of platelets = more bleeding
What is thrombocytosis?
increased number of platelets = increased clotting
What is megakaryocyte?
platelet progenitor cell
What are characteristics of megakaryocyte?
mulit-nucleated and increases in size as it matures due to platelet production
What is the hematopoietic process of platelets?
megakaryoblast > promegakaryoblast > megakaryocyte > metamegakaryocyte > platelet
How are platelets released from the metamegakaryocyte?
metamegakaryocyte lyses
What are characteristics of platelets?
non-nucleated | involved in homeostasis | contains many granules
Lifespan of platelets?
10 days
What are bleeding problems caused by?
decreased number of platelets | abnormal function
What is thrombocytopenia? What causes it?
decrease in number of platelets | decrease survival span and decrease in production
What is the normal value of platelets?
150K - 300K uL
What range indicates abnormal bleeding problem?
< 30K per uL
What are the 3 differential diagnoses for a decreased survival of platelets?
autoimmune disorders | bacterial infection | hyperactive spleen
How do autoimmune diseases such as SLE decrease the lifespan of platelets?
production of Ab against platelets
How can bacterial infections decrease the lifespan of platelets?
production of toxins that destroy platelets or make them stick to capillary walls = can’t circulate
How does a hyperactive spleen decrease the lifespan of platelets?
removes platelets super fast (and RBCs)
What are the 4 reasons why platelet production would be decreased?
viral/bacterial infection | excessive alcohol intake = cirrhosis = RBCs enlarge = ulcer | chemotherapy | malignancies
What is thrombocytosis?
increase production of platelets
What are the 5 causes of thrombocytosis?
abnormal platelet function | morphologically abnormal | bleeding problems | clumping of platelets when there is a lot of them | polycythemia vera
What is Polycythemia Vera?
increase in RBC and platelet production
What is a key symptom of Polycythemia Vera?
purpur
What is purpur?
minute bleeding spots throughout body , doesn’t clot