BL2 Haemopoiesis Flashcards
What is haemopoesis?
the process that forms blood cells and platelets, all of which orginate from a Pluripotent haematopoietic stem cell
What is the role of bone marrow in haemopoesis?
in adults it is where haemopoesis occurs
What is erythropoesis?
formation of red blood cells through differentiation of PHSC
1)What regulates erythropoesis? 2) Why is the switch off particularly important?
hypoxia activates fibroblasts in peritubular cells of the kidney so that they release the hormone/cytokine erythropoietin (EPO). EPO acts on bone marrow = 1) more stem cell turnover, 2) more maturation of RBC precursors( e.g. preerythroblasts), 3)increased rate of RBC release STITCH OFF: there must be a negative feedback loop, it is unknown atm, which = blood EPO drops. 2) it takes 1-3 days to appear so imagine at the 6 day mark there would be way too much RBC
In a cut sample of bone marrow how would you be able to identify the 1) active bone 2) inactive bone
1) red due to haemoglobin 2) yellow due to fat
What are granulocytes?
a white blood cell with secretory granules in its cytoplasm
What are the 5 major types of white blood cells ?
neutrophil, eosinophil, basophil, monocyte, lymphocyte
a) What are the 2 different groups of white blood cell? b) Which of the 2 groups do the major types of leukocytes fall under?
1) granulocytes, have granules in cytoplasm when stained and viewed in microscope b) neutrophil, eosinophil, basophil 2) agranulocytes, which do not have granules in the cytoplasm. b) monocyte, lymphocyte
What of the 5 major types of white blood cell are phagocytes?
monocytes, neutrophils
1) What is the name of monocytes in tissues? 2) what do basophils develop into? 3) the resultant cell of 2 was thought to release a substance but not anymore, what was that substance?
1) macrophages 2) mast cells 3) histamine
1)What are the 2 lineages of leukocytes? 2) Which line produces which of the 5 major cell types of leukocytes?
myeloid line and lymphoid line 2) a) Lymphoid= lymphocytes b) myeloid= monocytes, neutrophils, eosinophils and basophils
1)What are the 2 lineages of leukocytes? 2) Which line produces which of the 5 major cell types of leukocytes?
myeloid line and lymphoid line 2) a) Lymphoid= lymphocytes b) myeloid= monocytes, neutrophils, eosinophils and basophils
What is a progenitor cell?
a cell that is the commiited form of the white blood cell it will form in that cell’s lineage
A) What stages of forming a white blood cell in general: B) what is the only exception to these stages:
1)Pluripotent hematopoietic stem cell (PHSC) specialises into a myeloid or lymphoid stem cell (the other daughter stem cell remains a PHSC) 2) this specialises into other non-commmited stem cells 2) this eventually specialise into a committed stem cell called a progenitor cell, 3) differentiates into some other cells in the bone marrow (e.g. erythroblast and megakaryocyte) then enters blood as target cell B) erythrocytes specialise from reticulocytes in blood and not in bone marrow, so it is not “target” cell that enters blood in the case of erythrocytes
What is a progenitor cell?
a cell that is the commited form of the white blood cell it will form in that cell’s lineage
A) What stages of forming a white blood cell in general: B) what is the only exception to these stages:
1)Pluripotent hematopoietic stem cell (PHSC) specialises into a myeloid or lymphoid stem cell (the other daughter stem cell remains a PHSC) 2) this specialises into other non-commmited stem cells 2) this eventually specialise into a committed stem cell called a progenitor cell, 3) differentiates into some other cells in the bone marrow (e.g. erythroblast and megakaryocyte) then enters blood as target cell B) erythrocytes specialise from reticulocytes in blood and not in bone marrow, so it is not “target” cell that enters blood in the case of erythrocytes
What are the 3 lymphocytes?
natural killer cells ( larger granular lymphocyte), T cells (small lymphocyte), B cells (small lymohocyte)
1)In the active marrow, give the percentages of red blood cells and white blood cells that are formed: 2) WHy is this the case? 3) How long do RBC survive for? 4)What is the half life of neutrophils? 5) How many neutrohils must we make per day?
1)25% are destined to be red blood cells, 75%, white blood cells 2) leukocytes have a shorter life span so require more frequent replacing 3) up to 4 months 4) 6 hours 5) 100 million
What stimulates haematopoiesis?
cytokines which are peptides/proteins that are cell signalling molecules
Name 3 cytokines that stimulate haematopoiesis?
1) Erythropoietin(EPO) 2) Thrombopoietin(TPO 3) Colony-stimulating factors, 4) interleukins 5) stem cell factor
!)Where is Erythropoietin(EPO) synthesised? 2) WHat causes it to be produced? 3) WHat is its effect?
1) Kidney cells primarily, 2) Hypoxia factor one s switched on at low O2 conc of blood, it is a transcription factor that stimulates translation of gene coding for EPO 3) encourage production of RBC
A) What stages of forming a white blood cell in general: B) what is the only exception to these stages:
1)Pluripotent hematopoietic stem cell (PHSC) specialises into a myeloid or lymphoid stem cell (the other daughter stem cell remains a PHSC) 2) this specialises into other non-commmited stem cells 2) this eventually specialise into a committed stem cell called a progenitor cell, 3) differentiates into some other cells in the bone marrow (e.g. erythroblast and megakaryocyte) then enters blood as target cell B) erythrocytes specialise from reticulocytes in blood and not in bone marrow, so it is not “target” cell that enters blood in the case of erythrocytes
1) Where are the following cytokines produced? 2) What can they do?
1) endothelium and fibroblasts of bone marrow, leukocytes (which is useful as it means stronger immune response as leukocytes can encourage production of more similiar leukocytes during infection) 2) mobilise haematopoietic stem cells and influence growth or differentiation of all types of blood cells
!)Where is Erythropoietin(EPO) synthesised? 2) WHat causes it to be produced? 3) WHat is its effect?
1) Kidney cells primarily, 2) hypoxia , low O2 conc. 3) encourage production of RBC
1) Where are the following cytokines produced? 2) What can they do?
colony stimulating factor
interleukins
stem cell
1) endothelium and fibroblasts of bone marrow, leukocytes (which is useful as it means stronger immune response as leukocytes can encourage production of more similiar leukocytes during infection) 2) mobilise haematopoietic stem cells and influence growth or differentiation of all types of blood cells
1)What is EPO? 2) what assists it in producing RBC? 3) How does hypoxia leas to production of EPO
1) a cytokine that is a glycoprotein 2) several cytokines 3) switches on transcription factor, Hypoxia-inducible factor (HIF-1), encourages transcription of EPO gene= increase in RBC and therefore haemoglobin
What is the difference between hematopoiesis and erythropoiesis?
hematopoiesis is the overall process of the production of blood cells while erythropoiesis is a part of hematopoiesis which synthesizes red blood cells or erythrocytes.
What does Thrombopoietin(TPO) do? WHere is TPO produced?
1) a) stimlates platelet production by stimulating growth and maturation of megakaryocytes from megakaryoblasts ( progenitor cell ) 2) liver mainly but also kidney
What is the difference between hematopoiesis and erythropoiesis?
hematopoiesis is the overall process of the production of blood cells while erythropoiesis is a part of hematopoiesis which synthesizes red blood cells or erythrocytes.
Explain the stages of formation of RBC from progenitor cells ( name the cell as well):
1) the progenitor cell for RB cells is called proerythroblasts this developes into an erythroblast 2) erythroblasts pinch of the nucleus. Fully differentiated erythrocytes lack a nucleus 3) erythrocyte enters blood and is now called reticulocyte. 4) reticulocyte then loses mitochondria and ribosomes.