Intro Flashcards
What is the purpose of a complete blood count (CBC)?
- Haemoglobin level and cell counts
- Haemoglobin concentration
- Red cells: count, size, contents
- Leucocytes: count
- Platelets
- Blood film examination for morphology
Also known as a full blood screen (FBS).
What are the key components evaluated in a blood film examination?
- Morphology of red cells
- Platelets
- Leucocytes
This evaluation is qualitative in nature.
Where does haematopoiesis primarily occur in adults?
In the bone marrow, mainly in the axial skeleton (skull, vertebrae, ribs, sternum, pelvis)
In children, it includes the limbs; in fetuses, it mainly occurs in the liver and spleen.
What are the principles of regulation in haematopoiesis?
- Self-renewal of pluripotent stem cells
- Differentiation into specific cell lineages
- Cytokine signals inducing growth and differentiation
- Support from marrow stromal cells
Key cytokines include Erythropoietin (EPO) and thrombopoietin (TPO).
What is the role of Erythropoietin (EPO) in erythropoiesis?
It drives the production of red blood cells from proerythroblasts to mature erythrocytes
EPO is secreted by the kidney.
What are the three main types of anaemia based on cell size?
- Microcytic (MCV <80 fL)
- Normocytic (MCV = 80-99 fL)
- Macrocytic (MCV >99 fL)
Cell size parallels the amount of haemoglobin in a cell.
What is the WHO definition of anaemia for females and males?
- Female Hb <120 g/L
- Male Hb <130 g/L
Low haemoglobin indicates reduced ability to transport oxygen in blood.
What is the significance of reference intervals in blood tests?
They represent the central 95% of values obtained from healthy individuals of a specified population
Factors affecting reference intervals include age, sex, physiology, and ethnic differences.
What are the common causes of normocytic anaemias?
- Haemodilution after acute blood loss
- Renal failure (low EPO)
- Bone marrow failure or infiltration
- Anaemia of inflammation
These can lead to reduced red cell production due to decreased availability of iron.
What are the characteristics of macrocytic anaemias?
- Common in liver disease
- Caused by folic acid or vitamin B12 deficiency
- Delayed and abnormal maturation in marrow
This can lead to megaloblastic anaemia.
What is pancytopenia?
A condition where all three main lineages (Hb, platelets, neutrophils) are reduced
It indicates a more generalized problem in blood cell production.
What factors can affect the reference intervals for blood cell tests?
- Developmental age
- Sex
- Physiology (e.g., pregnancy, altitude)
- Ethnic (genetic) differences
These factors can lead to variations in normal ranges.
What is the significance of automated haematology analyzers?
They provide automated counts of blood cells based on size, complexity, and nucleic acid fluorescence
This technology improves precision in cell counts.
Fill in the blank: The primary measure of oxygen carrying in blood is _______.
Haemoglobin (Hb)
True or False: Haematopoiesis occurs only in the bone marrow of adults.
False
In fetuses, haematopoiesis occurs mainly in the liver and spleen.
What are the stages of erythropoiesis?
- Proerythroblast
- Erythroblasts
- Reticulocyte
- Mature erythrocyte
The process takes about 8-9 days in the marrow.
What does the term ‘erythroblast’ refer to?
A nucleated red blood cell during the development stage
Once it loses its nucleus, it becomes an erythrocyte.
What is the primary function of erythroblasts?
To produce haemoglobin
Erythroblasts proliferate and differentiate into red blood cells.
What do erythroblasts take up in large amounts?
Iron
Iron is essential for haemoglobin production.
What cellular components do erythroblasts remove as they mature?
Mitochondria, ER, ribosomes, golgi, nucleus
This process is part of erythroblast maturation leading to red blood cell formation.
True or False: Erythroblasts proliferate in later stages of development.
False
Erythroblasts proliferate only in the early stages.
Erythroblasts are often found surrounding which type of immune cell?
Macrophage
This interaction is important for erythropoiesis.
Fill in the blank: Erythroblasts proliferate in early stages only and take up large amounts of _______.
iron
