Haematopoiesis and disease Flashcards
Where does embryonic haematopoiesis occur?
Yolk sac, liver and spleen and bone marrow
Where does infant haematopoieses occur?
All of it is produced in the bone marrow
Where does adult haematopoiesis occur?
In the central skeleton as well as proximal ends of femur
difference between red bone marrow and yellow bone marrow?
red marrow is the part which produces the blood cells whereas the yellow marrow refers to the fat spaces.
How do all blood cells form?
Due to the hematopoietic stem cells (hemocytoblasts) present in the bone marrow.
thrombocytes is another word for…
Platelets.
What is noticed from this image?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/332/405/543/q_image_thumb.png?1610148336)
As the cells mature, the cells become smaller in size, and the presence of the nucleus no longer remains
HSC niche in the bone marrow?
HSC thought to be maintained by endothelial cells and stromal cells maintain them by secreting various factors.
signals help in survival and proliferation as well as homing and mobilisation.
Control of adult haematopoiesis is caused by:
extrinsic signalling (growth factors - survival/ proliferation, differentiation e.t.c) and intrinsic signalling (transcription factors)
example of Growth Factors and what they do?
Erythropoietin - regulates the production of RBC’s, predominantly produced by the kidneys and some in the liver. Production is stimulated by tissue oxygen levels.
Thrombopoietin - produced in the liver and controls platelet count in the bone marrow via a feedback mechanism
G-CSF, M-CSF, IL-5 - produced via myelopoiesis in the bone marrow
Normal peripheral blood is used to obtain a full blood count. How is a reference range formed?
The Blood counts are made using healthy populations and the mean +/- 95% CI is used to form the range.
Most common type of WBC?
Neutrophils
too many RBC?
Too many WBC?
Too many platelets?
Eryhtrocytosis
Leucocytosis
Thrombocytosis
Too little RBC?
Too little WBC?
Too little Platelets?
Too little of everything?
Anaemia
leucopenia
thrombocytopenia
pancytopenia
How can there be a malignant disorder?
There can be myeloproliferative disorders which lead to excess blood cell formation
Reasons for benign excess BC conditions?
erythrocytosis e.g. smoking, alcohol, altitude, lung disease
leucocytosis e.g. infection, inflammation
thrombocytosis e.g. iron deficiency, infection
cytopenias are caused by?
failure of production in the bone marrow, or excess loss or consumption in the periphery
symptoms of anaemia
lethargy, breathlessness, chest pain, headache/ dizziness, pallor
Leucopaenia is usually caused by…
Low neutrophil count. This is usually caused by cancer or due to a range of infections such as mouth ulcers, overwhelming sepsis.
What causes thrombocytopenia?
low platelet count (<150 x10^9/ litre)
symptoms caused by levels less than 20 x10^9/l
symptoms include bruising, gum bleeding, nose bleeds, petechiae, or even prolonged bleeding after cuts