hematopoiesis -Vishy Flashcards
What are granulocytes?
WBCs that have granules: neutrophils, basophils and eosinophils
What are agranulocytes?
lymphocytes and monocytes
Where are stem cells produced in development and life?
1st in the yolk sac
then in liver and spleen from the 3rd-7th month of development
in bone marrow from 7th month of development–> adulthood (ratio of differentiated: stem cells = 10^5: 1)
What are the two lineages of stem cells and what cells does each lineage produce?
- lymphoid: lymphoblasts–> prolymphocytes–> lymphocytes (T and B cells)
- myeloid:
- myeloblasts (monoblasts) –> promyelocyte–> neutrophils, basophils, eosinophils
- monoblasts–>monocytes
erythrocytes and platelets are also cells of myeloid lineage
At what stage is a hemocytoblast (stem cell) committed to becoming a erythrocyte?
proerythroblast
still has a nucleus, nucleolus and organelles at this stage but will eventually lose these when it develops into a mature RBC
What controls the development of stem cells into RBCs? (erythropoiesis)
erythropointin, which is secreted by the kidneys when oxygen is low.
iron
amino acids
B vitamins
What do primary granules of neutrophils contain? secondary granules?
Primary granules are azurophilic granules contain lysozyme, alpha-defensins and myeloperoxidase (catalyses the reaction producing hypochlorous acid and singlet oxygen, which can have antimicrobial effects)
secondary granules contain lactoferrin
Which cytokines regulate the formation of neutrophils from stem cells?
GM-CSF, CSF, IL-3
What cells are responsible for leading the body’s defense against parasitic infections?
eosinophils
Which cells have granules that contain histamine and play an important role in allergic reactions?
basophils (they are similar in function to mast cells, which also participate in allergic reactions)
what cytokine induces the formation of monocytes/macrophages from stem cells?
M-CSF (macrophage colony stimulating factor)
What cytokine causes stem cells to differentiate into lymphocytes?
IL-7
Describe the process of apoptosis
programmed cell death of blood cells prevents necrosis and the spilling of intracellular contents including enzymes, and preventing inflammation of blood cells.
cells undergoing apoptosis shrink and undergo blabbing. Cells break down into small “apoptotic bodies” which are then phagocytosed by macrophages.
What are some of the factors that can initiate apoptosis? Inhibit apoptosis?
initiate apoptosis: p53, Bax, BclXs (Bcl-short), FasL, and caspases
inhibit: Bcl-Xl (Bcl-long)