Haemopoiesis Flashcards
Definition
Formation of blood cells
What are blood cells derived from
Small pool of stem cells
Which of the following has the shortest life span
- platelets
- neutrophils
- red blood cells
Neutrophils
Which of the following has the longest life span:
- platelets
- neutrophils
- red blood cells
Red blood cells
What is the average life span for RBCs
120 days
What is the average lifespan for neutrophils
7-8 hours
What is the average lifespan for platelets
7-10 days
If bone marrow production was to stop suddenly, what would be the first to drop?
- platelets
- neutrophils
- red blood cells
Neutrophils (based on their lifespan)
Stem cells are able to self-renew. True or false?
True
Developmental events in haemopoiesis
- Stem cell self renewal
- Proliferation
- Differentiation (Lineage commitment)
- Maturation of descendents
- Apoptosis of descendants
Embryonically, where do haemopoietic stem cells originate?
Mesoderm
Name 4 sites of haemopoiesis in utero?
Mesoderm
Liver (starts at week 6)
Bone marrow
Spleen (starts at month 3)
In utero, at what stage in pregnancy does bone marrow haemopoiesis occur?
Month 4
week 16
At birth, what is the main site of haemopoiesis?
Bone marrow
In adults, what is the main site of haemopoiesis?
Bone marrow
- axial skeleton
- pelvis (PSIS)
- proximal long bones
Bone marrow biopsy in a young child is likely to be taken from which area of the body?
Tibia
Bone marrow biopsy in a young adult is likely to be taken from which area of the body?
Femur
Bone marrow biopsy in an adult is likely to be taken from which area of the body?
PSIS (most common)
Sternum
Bone marrow vasculature
Venous sinuses
When comparing sinuses and capillaries: sinuses are SMALLER/LARGER than capillaries and they have a CONTINUOUS/DISCONTINUOUS basement membrane ?
Larger
Discontinuous
Which marrow is actively producing red cells and platelets? Red or yellow?
Red
Which marrow is fatty and inactive. Red or yellow?
Yellow
There is an increase in red/yellow marrow with age?
Yellow
Describe the myeloid:erythroid ratio
Relationship of neutrophils (and precursors) to proportion of nucleated red cell precursors
The myeloid:erythroid ratio usually favours the myeloid (neutrophils)/erythroid (RBCs)? Why?
Myeloid (neutrophils)
- neutrophils have a shorter life span
In what situation might the myeloid:erythroid ratio favour the RBCs?
In haemolysis, as a compensatory response
What regulates erythropoiesis the most?
Concentration of Hb
How do we investigate non-lymphoid mature cells?
Routinely undertaken (this is often sufficient enough)
- blood count
- cell indices
- morphology
Specialist tests
- bone marrow examination
How do we investigate lymphoid mature cells?
Immunophenotyping
What is immunophenotyping?
Identify patterns of protein (antigen) expression unique to a cell lineage by using specific antibodies
What does stem cell harvesting involve?
Moving haemopoietic stem cells from bone marrow –> blood –> collect the blood
How do we assess normal, more mature non-lymphoid cells?
Morphology - blood count and blood film Cell surface antigens - glycophorin A = red cells Enzyme expression - myeloperoxidase = neutrophils
How do we assess/investigate normal progenitors/stem cells?
Immunophenotyping
Why is immunophenotyping instead of morphology required for assessing stem cells ?
Since the stem cells all look alike, they cannot be distinguished morphologically
