Week 2 Introduction to Haematology ✅ Flashcards
What are the most common WBC?
Neutrophils
What do neutrophils look like?
Multilobed nucleus
What is plasma made of?
Water and proteins
What is the composition of blood?
RBC
WBC
Platelets
Plasma
What are the functions of blood?
Transport gases, nutrients, wastes and hormones
Regulate pH, temperature, water and electrolytes
Protection - platelets, WBC
What is haematopoiesis?
Formation of blood cells from stem cells in bone marrow (sternum, pelvis, femur)
What is extramedullary haematopoiesis?
Haematopoiesis in liver, spleen and lymph nodes (organs involved in development)
When does extramedullary haematopoiesis occur?
Pathological conditions
What is an example of a pluripotent cell?
Stem cell
What is the difference between myeloid and lymphoid cells?
Myeloid:
RBC
Thrombocytes
Granulocytes (neutrophils, basophils, eosinophils)
Agranulocytes (monocytes and macrophages)
Lymphoid:
T lymphocytes
B lymphocytes
NK cells
What do growth factors do?
Stimulate production of leukocytes
What is CSF?
Colony stimulating factors
Are neutrophils part of adaptive or innate immunity?
Innate
What are the characteristics of neutrophils?
Multilobed nucleus, short lifespan, phagocyte, 70% WBC
What are the characteristics of monocytes?
Kidney bean shaped
only 8% WBC
Differentiates into the phagocytic macrophages
What are the characteristics of eosinophils?
Bi-lobed nucleus, red/orange stained granules
What are the characteristics of basophils?
Abundant dark purple cytoplasmic granules
What is an immature granulocyte called?
Band cell
What is the precursor of thrombocytes?
Megakaryocytes
How are thrombocytes formed?
Production stimulated by TPO
What does TPO stand for?
Thrombopoietin
Where is TPO produced?
Liver, kidney, bone marrow
What is the system that destroys old platelets? Where does this take place?
Mononuclear phagocyte system in liver and spleen
Where can platelets be stored?
In the spleen
What regulates TPO?
The binding or lack of binding of platelets to TPO
What is the precursor of an erythrocyte?
Reticulocyte
Where are reticulocytes released from?
Bone marrow
What are the features of Erythrocytes?
No nucleus
Bi-concave shape - maximise SA:V
What is erythropoiesis?
Production of erythrocytes
How are reticulocytes identified?
Free RNA stains to the same dye that nuclei stain with
What is precursor of reticulocyte?
Normoblast
What is EPO?
Stimulates erythropoiesis
What does EPO stand for?
Erythropoietin
Where is EPO produced?
Kidney
What stimulates EPO production?
High altitude or anaemia
What factors can affect erythrocyes?
Iron
Intrinsic factor
Vitamin B12
Folic acid
Where is the haemoglobin in RBC?
Cytoplasm
What are the protein chains in haemoglobin?
4 protein chains
2 alpha
2 beta
Where does iron bind to on haemoglobin?
Haem ring
What happens as O2 binds to each haem ring?
Protein changes shape
What is the average lifespan of an RBC?
120 days
When iron is absorbed from the diet, how is it carried in circulation?
Bound to transferrin
How is iron stored in macrophages and hepatocytes?
Bound to ferritin
How is circulating iron controlled?
Hepcidin
What condition could reduce the number or function or RBCs?
Anaemia
What condition could cause excessive number of RBCs?
Erythrocytosis/polycythaemia
What could affect haemostasis?
Deficiency in coagulation leading to bleeding
Excessive coagulation leading to thrombosis
What are the 4 common veins used in venepuncture?
Cephalic vein
Basilic vein
Median cubital vein
Median vein of forearm
What parameters can be measured for FBC?
RBC (x10^12/L)
MCV
Haematocrit
Haemoglobin g/L
Mean cell haemoglobin (pg)
Mean cell Hb concentration (g/L)
Red cell distribution width
WBC (x10^9/L)
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
What is haematocrit?
Volume percentage of red blood cells in blood
What is red cell distribution width?
Measures the range
What is the term for a low platelet count?
Thrombocytopenia
What is the term for a high platelet count?
Thrombocytosis
What can cause thrombocytopenia?
Reduced bone marrow production
Increased platelet destruction (autoimmune)
Sequestration
Abnormal bleeding
Spontaneous skin purpura
Mucosal haemorrhage
Prolonged bleeding
What can cause thrombocytosis?
Iron deficiency?
Inflammation
Cancer
Infection (reactive thrombocytosis)
Underlying myeloproliferative process
Where does sequestration occur? What does it mean?
Enlarged spleen
Pooling of too many cells in the spleen
What does a normal RBC look like on a blood film?
Central pallor 1/3 of diameter
What is a macrocytic RBC?
Larger cell
Normochromic
Howell-jolly body
Poikilocytosis
Anisocytosis
What does Holly-jolly body mean?
Remnants of nucleus which should have been removed by the spleen - seen often in splenectomy
What does poikilocytosis mean?
Variation in RBC shape
What does anisocytosis mean?
Variation in RBC size
What is a normocytic normochromic RBC?
Individual RBC normal but low number
What is a microcytic hypochromic RBC?
Smaller size, hypochromic, anisocytosis, poikilocytosis
What might you see in haemolytic anaemia?
Increase in reticulocytes, anisocytes and poikilocytes
If a RBC is macrocytic, what might the MCV be?
High
If a RBC is microcytic, what might the MCV be?
Low
What colour do reticulocytes stain?
Blue
What can cause anaemia?
Decreased RBC production
Increased RBC destruction
Blood loss
What should the reticulocyte count be in anaemia and what is it actually?
It is inappropriately low but should go up
What should the reticulocyte level be in normal people?
Low as they do not have anaemia
What are the 6 shapes of RBC?
Target cell
Sickle cell
Pencil cell
Spherocyte
Tear drop/poikilocyte
Basket cell
What can bone marrow examination be used for?
Infiltration malignant cells e.g. leukaemia
Bone marrow disorders
Where can bone marrow be aspirated from?
Posterior iliac crest
What does healthy bone marrow aspiration show?
Heterogenous mixture of cells of various lineages at all cells of differentiation. Myeloid cells predominating over lymphoid
What does fibrosis of bone marrow in a biopsy show?
Dry tap
Why do a bone marrow biopsy?
To examine bone structure
What is the findings of normal bone marrow on a biopsy?
50% haematopoietic, 50% fat tissue