Haematopoesis Flashcards
(21 cards)
What is haematopoesis ?
The formation and development of blood cells
Where do the cells come from?
Bone marrow
What are the richest sources of bone marrow ?
Hip and vertebral bone (spine).
What is red bone marrow?
Produces blood cells
What is yellow bone marrow ?
Mainly fat
Where is red marrow found ?
Found flat bones.
And epiphysis ends of long bones (femur, tibia, humerus)
What regulates the development of blood cells?
External and internal protein factors.
What causes haematopoitic stem cells to differentiate ?
Probability of stem cells death.
Frequency of stem cell division.
Probability that stem cell daughter will become,e a committed progenitor cell of the given type.
What causes common progenitors to differentiate ?
Division cell type of committed progenitor cell.
Probability of progenitor cell death.
What causes committed progenitors to differentiate ?
Number of divisions before terminal differentiation.
What causes mature cells to differentiate ?
Lifetime of differentiated cells
What factor causes differentiation into erythrocytes (red blood cells)
Erythropoietin (EPO)
What is the final stage before an erythrocyte is fully matured ?
Reticulocyte
What is a reticulocyte ?
Have no nucleus
Some ribosomes
Still got some organelles
How is thrombopoiesis Regulated ?
Production of platelets is regulated by their own level in the blood stream.
How are the levels of thrombopoitin regulated in the blood?
High levels of platelets degrades thromobopoitin results in less signaling to bone marrow.
Low levels of platelets mean there more thromobopoitin in the blood so there more signaling to the bone marrow.
Where are red blood cells broken down ?
Liver
Spleen
bone marrow.
What’s the lifespan of red blood cells?
120 days
What break down red blood cells and where ?
Macrophages in the spleen, liver, and bone marrow.
What causes the kidneys to produce more erythropoietin?
Low oxygen levels
What cells in the kidneys produce erythropoietin?
Produced by endothelial cells of the peritubular capillaries in the renal cortex.
