Haematopoiesis Flashcards
What are the main classes of blood cells?
red cells
platelets
white cells
What are the classes of white cells. give examples of each
Lymphoid: T cells, B cells, NK cells
Myeloid: monocytes, eosinophil, basophil, neutrophil
Draw the haematopoiesis development tree.
See lecture
Describe the structure and function of platelets.
What is their lifespan? What are they removed by?
- no nucleus, granules which secrete substances which control clotting and breakdown of a blood clot
- they also form part of the blood clot themselves
- 8-12 days, removed by macrophages in the spleen and liver
Name three granulocytes
Neutrophils - engulf bacteria, granules contain lysosyme and myeloperoxidase
Eosinophils - allergy, atopy, parasite infections
Basophils - allergy, atopy
What are monocytes?
Can migrate from blood into tissues and become macrophages
Engulf and destroy dead cells, bacteria, protozoa, fungi
What is the general structure of lymphocytes?
What are the three lymphocytes?
- small cells with low granularity
B cells - develop in bone marrow
T cells - early progenitor from bone marrow, develop the in thymus
Natural Killer cells - develop in bone marrow
What are some other cells produced by haematopoesis?
dendritic - antigen presenting cells
mast cells - produced in bone marrow but nature in tissues
List the following order of abundance.
- neutrophils, lymphocytes, red cells, platelets
red cells 5 x10^12/L
platelets 150-450 x10^9/L
neutrophils 2-8 x10^9/L
lymphocytes 1-4 x10^9/L
What are the lifespans of the following? red cells neutrophils platelets lymphocytes
- 120 days
- <48 hours
- 8-12 days
- years?
At what point after fertilisation does haematopoesis begin?
17 days
How many cells arise daily from bone marrow?
10^12
What is stem cells?
Haemopoetic stem cells are ………potent
Can divide indefinitely so it can replenish itself and give rise to specialised, differentiated cells
Multi
What is the pathway from SC’s to mature cells?
Stem cells
Progenitor
Precursor
Mature
Where is the site of haematopoesis at the following times?
- 17 days
- 2 months
- 2-7 months
- 5-9 months
- Infants
- Adults
- yolk sac
- aorta, gonad, mesonephros
- placenta
- fetal liver
- bone marrow
- virtually all bones
- axial skeleton
What growth factors are required for progression into each mature cell?
erythropoetin (EPO) –> erythrocytes
thrombopoetin (TPO) –> platelets
granulocyte colony stimulating factor (G-CSF) –> monocytes, neutrophils, eosinophils
What are the granulocyte maturation stages?
myeloblast promyelocyte myelocyte metamyelocyte band mature neutrophil (similar for eosionphils and basophils)
What are the monocyte maturation stages?
monoblast –> promonocyte –> monocyte
Describe the control of erytrhopoesis
Low O2 detected in kidneys
EPO released from peritubular interstitial cells of outer cortex
This acts at several stages of erythopoetin maturatoin
What are the erythrocyte maturation stages?
proerythroblast erythroblast early intermediate late reticulocytes red cells
What is special about a reticulatyte in terms of genetics?
Has no nucleus but contains RNA so can make Hb
What TF controls platelet production? Where is this realised? Where is the receptpr?
TPO
released from the liver
receptor on megakaryoblast, magakaryocyte and platelets
What are the platelet maturation stages?
stem cell megakaryocyte progenitors immature megakaryocyte mature megakaryocyte platelets
What are each of the the following growth factors used for in clinical practice?
EPO
TPO
EPO = used to improve anaemia, mainly used for end stage renal disease TPO = used when immune system destroys platelets e.g. post chemo, myelodysplasia, thrombocytopenia
Define:
- leukaemias
- lymphomas
- myelomas
- myeloproliferative disease and myelodysplasia
- malignancies of haematopoietic cells which arise in marrow and spread to involve blood, lymph nodes/spleen
- malignancies of lymphoid cells which arise in lymph nodes /spleen and spread to involve blood and marrow
- malignancy of plasma cells (in marrow)
- neoplastic chronic abnormal myeloid proliferation (preleukaemia)
What is the difference in causes between acute myeloblastic leakaemia and chronic myeloid leukaemia?
AML = maturation arrest causes acute leukaemia CML = no maturation arrest leads to over-production of mature cells
How can leukaemias be classified?
lineage e.g. myloid or lymphoid
maturation arrest or not e.g. acute or chronic
