Normal Haemopoiesis Flashcards
Define Haemopoiesis.
Formation of blood cells. Occurs mainly in bone marrow.
In adults, normal haemopoiesis forms…
Skull. Vertebrae. Ribs. Scapulae. Iliac crest.
In children, normal haemopoiesis forms…
All skeletal bones.
Define Myelopoiesis.
Multipotent HSC can differentiate into multipotent progenitors (MPP).
Define myeloid progenitors e.g. granulocytic cells.
Eosinophils. Neutrophils. Basophils. Mast Cells.
Define Erythropoietin.
Necessary for all stages of red cell development.
When is Erythropoietin mainly produced?
Mainly produced by kidney in response to hypoxia. Red cell nucleus lost, before reticulocyte and mature erythrocyte stages.
Define Thrombopoiesis.
Haemopoietic stem cells (HSCs) can differentiate into megakaryocyte-erythroid progenitors (MEPs) - then megakaryocytes, platelets.
Thrombopoietin (TPO), interleukin (IL-6) and other cytokines stimulate…
Maturation of megakaryocytes.
Which organ produces Thrombopoietin (TPO)?
Liver.
Define Lymphopoiesis.
Common lymphoid progenitors, with both B and T cell potential, originate in the bone marrow.
Where are B lymphocytes formed?
Bone marrow. Migrate to secondary lymphoid tissue e.g. lymph nodes, mucosa-associated lymphoid tissue (MALT), spleen.
What process results in the proliferation and differentiation of activated B lymphocytes into plasma cells?
Somatic hypermutation.
What are Natural Killer Cells?
Cytotoxic lymphocytes that do not express T cell receptors. Kill virally infected cells and tumour cells without differentiation.
State a feature of a Red Cell.
Mature red cell in blood - lost its nucleus. Biconcave shape with large surface area for O2 exchange. Lack of organelles means red cell is flexible and easily deform to pass through capillaries and splenic sinusoids. Haemoglobin. Uptake of oxygen from lungs and delivery to tissues.
State 2 white blood cells.
Lymphocytes. Neutrophils. Monocytes. Basophils. Eosinophils. Dendritic cells.
State a feature of neutrophils.
Circulate in blood before migrating to tissues. Lifespan in blood of around 7-10hrs and in tissues 1-2 days.
What colour do neutrophils stain with May-Grunulalde?
Lilac.
State a function of Neutrophils.
Margination (adhesion of white blood cells of walls of damaged vessels). Adhesion to endothelium. Killing and digestion of microorganisms. Phagocytosis and digestion of dead cells and cellular debris.
State a feature of Eosinophils.
Larger than neutrophils. Nucleus is usually bi-lobed. On MGG - stained orange/brick red. Synthesise and secrete growth factors, cytokines and chemokines. Trigger the release of histamine by basophils and mast cells (control infection by parasites). Attack parasites by degranulation and peroxidase-mediated generation of reactive O2 species.
State a feature of Basophils.
On MGG-stained films (dark purple). Nucleus bilobed. Cytoplasm contain scattered glycogen particles, golgi and few mitochondria. Involved in allergy, anaphylaxis and chronic inflammation.
What colour are Monocytes stained?
MGG stain - opaque greyish-blue.
State a function of Monocytes.
Phagocytosis and killing of microorganisms e.g. mycobacteria, listeria and fungi. Antigen-presenting cells. Immune modulator - secrete IL-1, IL-6, IL-12, tumour necrosis factor, interferon alpha and beta.
Lymphocytes can be divided into which cells…
B cells. T cells. Natural killer (NK) cells.
State the 3 types of haematological malignancies.
Myeloid. Lymphoid. Dendritic.
State 3 types of Myeloid Malignancies (arise from different stages of myeloid maturation).
Myeloproliferative neoplasms. Myelodysplastic neoplasms. Acute myeloid leukemia.
State 3 types of lymphoid neoplasms.
B, T and Natural Killer Cells.
Define chronic myeloid leukemia.
Arise from haemopoietic stem cell. Always associated with BCR-ABL1 fusion gene due to t(9,22) Philadelphia’s chromosome.
State a clinical feature of chronic myeloid leukemia.
Elevated white cell count. Fatigue, malaise, weight loss, night sweats. Splenomegaly. WBC > 50,000 - immature myeloid cells, basophils, eosinophils.
Define the prognosis of CML.
Transformed into 5yr survival of over 90%. PCR-based tests - used for monitoring response to treatment and diagnosing treatment failure. Tests are available to detect mutations within BCR-ABL gene.
