Leucocytes Flashcards
Which cells are granulocytes?
Neutrophils, eosinophils, basophils
Explain what granulopoiesis is & where it happens in the BM
The HSC undergoes specific differentiation in response to cytokines
Early precursors are adjacent to the bony trabeculae
They must be adjacent to the bony trabeculae as there are cytokines that are being liberated from the cells adjacent to the trabecular bone which drive the HSC down the granulocytic pathway
The maturing forms of WBCs are deeper in the marrow space (interstitium/middle)
where the nucleus matures and the cytoplasm granulates
then they will be released into the bloodstream
Where is granulopoiesis taking place in the BM?
The most immature granulocytic cells are located adjacent to the trabecular bone, and this is where granulopoiesis commences, as those cells get access to cytokines from there
Then the cells undergo differentiation and they move into the middle of the BM (darker, more purple stains)
What is the frequency of neutrophils?
40 - 75% of WBC are neutrophils
Explain the process of differentiation into neutrophils:
Myeloblast Promyelocyte Myelocyte Metamyelocyte Band form Neutrophil
Neutrophil maturation
There is a reduction in size during differentiation
The nucleus becomes condensed, and the chromatin becomes more condensed
What does neutrophil contain?
Neutrophils contain primary and secondary granules:
Primary granules (azurophilic) are also in eosinophil and basophil Secondary granules are specific to the neutrophil
granules contain enzymes
granules are in the cytoplasm
Neutrophil nucleus, function and movement
Neutrophil nucleus segments are 2-5
Females have drum-stick like appendages
Neutrophils come out into the circulation, they can be counted and seen in the blood, but they don’t stay in the nucleus for long as they move to the tissues to combat infection and remove debris
neutrophils have a phagocytic function
When is the primary granule formed?
At the promyelocyte stage
