NORMAL HAEMOPOIESIS Flashcards
(25 cards)
What is haemopoiesis?
The process of blood cell production, development, and differentiation within the bone marrow.
What are the main components of blood?
Blood is composed of:
* Plasma (55% of total blood volume)
* Cellular Components (45% of blood volume):
* Erythrocytes (RBCs)
* Leukocytes (WBCs)
* Thrombocytes (Platelets)
What occurs during the Mesoblastic Phase of haemopoiesis?
Blood cell production occurs in the yolk sac.
What is the primary site of haemopoiesis during the Hepatic Phase?
The liver is the primary site of haemopoiesis, assisted by the spleen.
Which phase of haemopoiesis takes over as the major site in adulthood?
The Myeloid Phase, where bone marrow becomes the major site of haemopoiesis.
What is the role of haemopoietic stem cells?
They can differentiate into all blood cell lineages and have properties of self-renewal and differentiation.
What are progenitor cells?
Cells derived from stem cells that are committed to a specific lineage and progressively lose their ability to differentiate into multiple cell types.
What is the function of stromal cells in bone marrow?
They support haemopoiesis by producing essential growth factors and forming a microvascular network for nutrient and oxygen supply.
What are haemopoietic growth factors?
Glycoprotein hormones that regulate the proliferation, differentiation, and function of blood cells.
Name major sources of haemopoietic growth factors.
- T-lymphocytes
- Monocytes
- Stromal cells
- Erythropoietin (EPO) from the kidney
- Thrombopoietin (TPO) from the liver
What is erythropoiesis?
The process of red blood cell formation, producing 10¹² erythrocytes per day.
List the stages of erythropoiesis.
- Proerythroblast
- Basophilic Erythroblast
- Polychromatophilic Erythroblast
- Orthochromatic Erythroblast (Normoblast)
- Reticulocyte
- Mature RBC
What is the key regulator of erythropoiesis?
Erythropoietin (EPO).
Fill in the blank: EPO is produced _____% by the kidney and _____% by the liver.
90% by the kidney and 10% by the liver.
What stimulates the production of erythropoietin?
Low oxygen levels in kidney tissues.
What is leukopoiesis?
The formation of white blood cells (WBCs).
Differentiate between the myeloid and lymphoid lineages in leukopoiesis.
Myeloid lineage produces granulocytes (neutrophils, eosinophils, basophils) and monocytes; lymphoid lineage produces B cells, T cells, and NK cells.
What are the types of granulocytes?
- Neutrophils
- Eosinophils
- Basophils
What is thrombopoiesis?
The formation of platelets from megakaryocytes.
What is the precursor cell for platelets?
Megakaryoblast.
How long does it take for platelets to mature from differentiation?
Approximately 10 days.
What regulates thrombopoiesis?
Thrombopoietin (TPO) produced by the liver and kidney.
List additional factors that promote platelet formation.
- IL-3
- IL-6
- IL-11
True or False: Erythropoiesis is regulated by growth factors like IL-3 and GM-CSF.
False. Erythropoiesis is primarily regulated by EPO.
