Haemopoiesis

Question 1

what is haemopoiesis?

Answer 1

• production of blood cells in bone marrow, happens in pelvis, sternum, skull, ribs and vertebrae.

Question 2

what determines the differentiation of the haemopoietic cells?

Answer 2

• 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.

Question 3

name some characteristics of haemopoietic stem cells.

Answer 3

• self renewal.
• can differentiate into specialised cells.
• pathological conditions can mobilize into circulation for extracellular haemapoiesis.

Question 4

what are some sources of stem cells?

Answer 4

• bone marrow aspiration.
• GCSF mobilised into peripheral blood stem cells.
• umbilical cord stem cells.

Question 5

what is the reticuloendothelial system?

Answer 5

• 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.

Question 6

differentiate between red pulp or white pulp in the spleen.

Answer 6

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.

Question 7

name a few functions of the spleen in adults.

Answer 7

• sequestration and phagocytosis.
• blood pooling and mobilising during bleeding.
• extra-medullary haemopoiesis proliferating stem cells.
• immunological function.

Question 8

name some causes for splenomegaly.

Answer 8

• 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.

Question 9

how would you examine a spleen?

Answer 9

• 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.

Question 10

what is the main risk with HYPERsplenism?

Answer 10

• 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)

Question 11

name some causes of HYPOsplenism.

Answer 11

• 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.

Question 12

whats the main risk with HYPOsplenism?

Answer 12

• risk of sepsis from encapsulated bacteria like meningococcus, streptococcus pneumonia.
• antibiotic prophylaxis given.

Question 13

what is the function of red blood cells?

Answer 13

• deliver O2 to tissues.
• carry HB.
• maintain reduced HB in ferrous state.
• generate energy.

Question 14

what is the structure of harmoglobin?

Answer 14

• 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.

Question 15

describe the steps of degradation of Haem.

Answer 15

• 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).

Question 16

distinguish between cytopenia, …cytosis and …philia.

Answer 16

• cytopenia is reduction in number of blood cells.

- the other 2 is an increase.

Question 17

what does GCSF and cytokines do to neutrophils?

Answer 17

• increase production.
• speed up release and maturation.
• enhance chemotaxis.
• enhance phagocytosis and killing of pathogens.

Question 18

what does GCSF and cytokines do to neutrophils?

Answer 18

• 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.

Question 19

what causes neutrophilia?

Answer 19

• an increase in absolute number of circulating neutrophils.

- infection, tissue damage, smoking, myeloproliferative diseases, GCSF.

Question 20

what causes neutropenia?

Answer 20

• reduction of production : infiltration, drugs, viral infection, congenital.
• increase removal or use : immune destruction, sepsis, splenic pooling.

Question 21

what are some consequences of neutropenia?

Answer 21

• severe life threatening bacterial infection.
• severe fungal infection.
• mucosal ulceration.
• neutropenic sepsis needs IV antibiotics must be given ASAP.

Question 22

what causes monocytosis?

Answer 22

• bacterial infection.
• inflammatory conditions.
• carcinoma.
• myeloproliferative disorders and leukemias.

Question 23

what causes eosinophilia?

Answer 23

• common in allergic diseases, parasitic infections, drug hypersensitivity, skin diseases.
• rare Hodgkin’s lymphoma, acute myeloid leukemia, acute lymphoblastic lymphoma,

Question 24

what causes basophilia?

Answer 24

• reactive in hypersensitivity reactions, ulcerative colitis, rheumatoid arthritis.
• myeloproliferative in CML.

Question 25

what causes lymohocytosis?

Answer 25

• reactive in viral and bacterial infections, stress related, MI.
• lymphoproliferative in CLL, lymphoma where cells spill out of infiltrated bone marrow.