Haemopoiesis Flashcards
what is haemopoiesis?
- production of blood cells in bone marrow, happens in pelvis, sternum, skull, ribs and vertebrae.
what determines the differentiation of the haemopoietic cells?
- hormones like erythropoietin (from kidney to make more RBC when 02 low) or thrombopoietin (from liver and kidney to regulate platelets).
- transcription factors.
- interactions with non-haemopoietic cells.
name some characteristics of haemopoietic stem cells.
- self renewal.
- can differentiate into specialised cells.
- pathological conditions can mobilize into circulation for extracellular haemapoiesis.
what are some sources of stem cells?
- bone marrow aspiration.
- GCSF mobilised into peripheral blood stem cells.
- umbilical cord stem cells.
what is the reticuloendothelial system?
- made up of monocytes in blood and a network of tissues which contain phagocytic cells, main organ being spleen and liver.
- removes dead or damaged and identify and destroy foreign antigens.
- spleen disposes blood cells, esp. old RBC’s.
differentiate between red pulp or white pulp in the spleen.
BLOOD VIA SPLENIC ARTERY.
- red pulp is the tissue made of sinuses lined by endothelial macrophages and cords. RBC go through.
- white pulp is the tissue similar in structure to lymphoid tissue mainly made from WBC.
name a few functions of the spleen in adults.
- sequestration and phagocytosis.
- blood pooling and mobilising during bleeding.
- extra-medullary haemopoiesis proliferating stem cells.
- immunological function.
name some causes for splenomegaly.
- portal hypertension in liver disease causing back pressure.
- over working due to high RBC?
- extramedullary haemapoiesis.
- expansion due to infiltration from metastases.
- infiltrated by other material like granulomas.
how would you examine a spleen?
- palpate right iliac fossa and feel for spleen edge moving towards your hand on inspiration as diaphragm goes down spleen hits hand.
- feel for splenic notch.
what is the main risk with HYPERsplenism?
- low blood counts that occur due to pooling of blood causes enlarging of spleen.
- risk of rupture as if enlarged no longer protected by spleen. (avoid sports and vigorous activity)
name some causes of HYPOsplenism.
- lack of functioning splenic tissue, howell jolly inclusion bodies which are RBC with DNA seen in blood film.
- splenectomy.
- sickle cell may cause atrophy in spleen.
- GI diseases like coeliac, crohns, ulcerative.
- autoimmune like lupus, rheumatoid arthritis, hashimotos.
whats the main risk with HYPOsplenism?
- risk of sepsis from encapsulated bacteria like meningococcus, streptococcus pneumonia.
- antibiotic prophylaxis given.
what is the function of red blood cells?
- deliver O2 to tissues.
- carry HB.
- maintain reduced HB in ferrous state.
- generate energy.
what is the structure of harmoglobin?
- tetramer of 2 pairs og globin chains each with own haem group.
- different globin chains pair up to form different functioning haemoglobin.
- fetal –> normal in first 3-6 months.
describe the steps of degradation of Haem.
- old RBC engulfed by macrophages and beoken down.
- haem broken down to bilurubin travels in blood unconjugated bound to albumin and FE2+ recycled.
- taken up by liver and conjugated with glucuronic acid and secreted in bile into duodenum.
- glucaronic acid removed by bacteria and bilirubin eventually to urobilin and excreted in urine (yellow).
distinguish between cytopenia, …cytosis and …philia.
- cytopenia is reduction in number of blood cells.
- the other 2 is an increase.
what does GCSF and cytokines do to neutrophils?
- increase production.
- speed up release and maturation.
- enhance chemotaxis.
- enhance phagocytosis and killing of pathogens.
what does GCSF and cytokines do to neutrophils?
- increase production.
- speed up release and maturation.
- enhance chemotaxis.
- enhance phagocytosis and killing of pathogens.
- given when more neutrophils needed after chemo or at severe neutropenia.
what causes neutrophilia?
- an increase in absolute number of circulating neutrophils.
- infection, tissue damage, smoking, myeloproliferative diseases, GCSF.
what causes neutropenia?
- reduction of production : infiltration, drugs, viral infection, congenital.
- increase removal or use : immune destruction, sepsis, splenic pooling.
what are some consequences of neutropenia?
- severe life threatening bacterial infection.
- severe fungal infection.
- mucosal ulceration.
- neutropenic sepsis needs IV antibiotics must be given ASAP.
what causes monocytosis?
- bacterial infection.
- inflammatory conditions.
- carcinoma.
- myeloproliferative disorders and leukemias.
what causes eosinophilia?
- common in allergic diseases, parasitic infections, drug hypersensitivity, skin diseases.
- rare Hodgkin’s lymphoma, acute myeloid leukemia, acute lymphoblastic lymphoma,
what causes basophilia?
- reactive in hypersensitivity reactions, ulcerative colitis, rheumatoid arthritis.
- myeloproliferative in CML.
what causes lymohocytosis?
- reactive in viral and bacterial infections, stress related, MI.
- lymphoproliferative in CLL, lymphoma where cells spill out of infiltrated bone marrow.
