Haematopoiesis (physiology) Flashcards
Process that gives rise to formed elements?
Haematopoiesis
Define the monophylatic theory of haematopoiesis
All formed elements are derived from a common ancestral cell, a stem cell.
What is the route of erythrocyte formation from stem cell?
-Hemocytoblast (stem cell)
-Proerythroblast (committed cell)
-Early erythroblast (ribosome synthesis, phase1)
-Late erythroblast (hemoglobin accumulation, 2)
-Normoblast (ejection of nucleus, phase 3)
-Reticulocyte
-Erythrocyte
Where does erythropoiesis occur?
In red bone marrow.
Which substances/molecules does erythropoiesis require? (6)
-Lipids, proteins and carbohydrates.
-Iron, vit b12 and folic acid.
Main function of platelets
Blood clotting
Where are platelets recycled and what recycles them?
In the spleen, by phagocytes.
Role of platelets in hemostasis (3)
-Plugging holes to the blood vessels to prevent bleeding.
-Promoting the formation of clots to further prevent bleeding.
-Help to repair the damaged blood vessels.
From which cell do platelets derive, and where does the thrombopoiesis occur?
Megakaryocyte, in the bone marrow.
Two ways in which platelets are released from megakaryocytes.
-Pinching off from the megakaryocyte into circulation.
-Passage of mature megakaryocyte into circulation and fragmentation in pulmonary vascular bed.
Diff btwn inactivated and activated thrombocytes.
Inactive are small, disc-like fragments.
Active have a spiky outer surface and they adhere to each other.
Hormonal control of thrombopoiesis
-Interleukin 6
-Thrombopoietin
-Multi-CSF