haematopoiesis and cell breakdown Flashcards
what is the rate of cell production and cell destruction?
3x10^6/s
Where does haematopoeisis initially occur and then where after
initially occurs in the yolk sac, then embryonic liver and then spleen
Where does haematopoiesis only occur at birth
myeloid tissue in red bone marrow
Where does haematopoiesis occur in healthy adults
proximal long bones, ribs, sternum, vertebrae
What are features of bone marrow
- Thicker than blood
- delicate mesh of reticular tissue
- contains immature blood cells
What percentage of bone marrow is pluripotent stem cells
0.05-1%
What is bone marrow thicker than
thicker than blood
What can be found in the bone marrow in reference to blood cells
Immature blood cells,monocytes
and adipocytes
How many new blood cells does the bone marrow produce every day
Produces 100 billion newcells
every day
What is bone marrow aspirate
liquid sample that contains fragments of bone marrow
How can leukaemias be categorised
can be categorised by morphology
What is a haemoblast
it is a Haematopoietic Stem Cell
What are properties of haemoblasts
- There are very few of them
- They can self-renew
- They have the capacity to develop into different cell types
What percentage of red bone marrow cells are haemoblasts
0.05-0.1% of red bone marrow cells
What are the different cell types that haemoblasts can become
bone, cartilage and muscle
Why is proliferation and differentiation needed
to produce a variety of mature blood cells with specialised functions from progenitor cells
What is differentiation
the stepwise changes that occur over successive generations of cells that result in specialised function
What are cells are of myeloid lineage
Erythroid series (red blood cells)
Granulocytic series (neutrophils, monocytes/macrophages, eosinophils, basophils)
Megakaryocytes (platelets)
What cells are of lymphoid lineage
B and T lymphocytes and related cells
What does erythropoietin do
stimulates RBC production
What does thrombopoietin do
stimulates platelet formation
What do cytokines do in respect to WBC formation
stimulates WBC formation
What can myeloid stem cells develop into
- Colony forming unit – erythrocyte [CFU–E]
- Colony forming unit – megakaryocyte [CFU–Meg]
- Colony forming unit – Granulocyte Macrophage [CFU–GM]
Explain the process for blood cell removal
- Red blood cell death and phagocytosis occurs
- splits RBC into heme and globin
3.on the globin route, globin broken down to amino acids which are reused for protein synthesis
- on the Heme route, broken down to [Fe3+ + transferrin] and biliverdin.
- on Fe3+ route, the complex goes to the liver and becomes ferritin and leaves the liver, becoming the initial complex again
- Fe3+ dissociates from transferrin and travels to the red bone marrow.
- Fe3+, Globin and vitamin B12 undergo erythropoiesis via stimulation of erythropoeitin
- New red blood cells are formed
- In BILIVERDIN route, biliverdin turns into bilirubin.
- bilirubin travels to liver and then small intestine and then large intestine
- in large intestine, bilirubin associates with bacterial enzymes to become Urobilinogen
- Urobilinogen is broken down into Urobilin and Stercobilin
- urobilin goes to the kidneys and is passed out in urine
- Stercobilin goes through the large intestine and is passed out as faeces
