Hematopoiesis Flashcards
(34 cards)
Blast cells
Are mitotic but not self-replication
As cells develop they…
lose potentiality, their nuclei shrink, nucleoli disappear, and specific features develop
Erythroid precursors are outnumbered by granulocytic precursors by what ratio?
3:1
How many days do erythrocytes take to develop? Where do they develop?
Approx. 7 days; in the bone marrow
How many days do granulocytes take to develop?
Approx. 14 days
What change occurs in marrow as humans age?
Fat in marrow increases with age
Bone marrow has more ___ cells than ___ cells
Mature; blast
Least mature erythrocytic cell type seen in peripheral blood
Reticulocytes
Least mature granulocytic cell type seen in peripheral blood
Band cells
How long are erythrocytes reticulocytes after release from the bone marrow?
About one day
How long do erythrocytes last in peripheral blood after release from the bone marrow?
About 120 days
How long do neutrophils last in peripheral blood after release from bone marrow?
From hours - one day
Do you see stem cells or progenitor cells in the bone marrow?
No, not unless you use cell markers for them
Important growth factors to know:
Erythropoieten, GM-CSF, G-CSF, IL-3, Thrombopoieten
Location of erythropoiesis in fetal life:
Early fetus = mesodermal cells of yolk sac; 3-4 months = liver and spleen; post 7 months = bone marrow “medullary hematopoiesis” – Liver and spleen can resume production is necessary “extramedullary hematopoiesis
Location of erythropoiesis in adult life:
Bone marrow
Difference between red and yellow marrow
RBCs, platelets and most WBCs arise red marrow; some WBCs develop in yellow marrow. Color of yellow marrow is due to high number of fat cells.
What is the role of macrophages in erythroblastic islands?
Erythroblastic islands are specialized microenvironmental compartments in the bone marrow where erythroblasts proliferate and differentiate. These islands consist of a central macrophage that extends cytoplasmic protrusions to a ring of surrounding erythroblasts. The macrophages provide nutrients, proliferative and survival signals to the erythroblasts, and phagocytose extruded erythroblast nuclei at the conclusion of erythroid maturation.
How do megakaryocytes extend their cytoplasmic processes into sinuses?
By dynein motors
What is contained within granules in platelets?
Growth and clotting factors, vasoactive substances
What are CFUs?
Colony forming units are progenitor cells that can differentiate into a limited number of cell types
What are Keratinocytes?
They are the dominant cells of the epidermis, they make keratin!!
Which hematopoietic cells have the greatest mitotic activity?
Blast cells
What is the most important interleukin to stimulate the production of all myeloid cells and what cells produce it?
IL-3; produced by T-lymphocytes
