Haematology III Flashcards
What are the different types of white blood cells?
- Leukocytes
- Neutrophils
- Lymphocytes
- Monocytes
- Eosinphils
- Basophils
What is the buffy coat?
the layer that exists between the blood cells in the bottom of a test tube and the plasma at the top. It is a thin layer that consists of the platelets and white blood cells
Why is there a larger buff layer in leukaemia?
due to increased WBCs
Give features of haematopoiesis for WBCs
- Lymphocytes derived from common lymphoid progenitor
- Rest of the white blood cells derive from common myeloid progenitor. Myeloid progenitor produces myeloblast which differentiates into either a basophil, neutrophil, eosinophil or monocyte
What are white blood cells also known as?
Leukocytes
What is a common physical characteristic across all white blood cells?
They are all nucleated
What are the roles of WBCs?
- Defence vs pathogens
- Toxins and waste removal
- Remove damaged cells
Where do WBCs mainly act?
outside tissues – in transit between sites of activity
What are the characteristics of WBCs?
- All can migrate out of the bloodstream. When WBCs in the bloodstream are activated they contact and adhere to the vessel walls in a process called margination. After further interaction with endothelial cells the activated SBCs squeeze between adjacent endothelial cells and enter the surrounding tissue. This process is called emigration or diapedesis
- All are capable amoeboid movement (most common mode of locomotion in eukaryotic cells – almost like a crawling movement)
- Neutrophils, eosinophils and monocytes are capable of phagocytosis
- All are attracted to specific chemical stimuli (when something is injured it releases chemicals and the leukocytes travel there)
What is the normal WBC count?
Approximately 4-11 x 10^9/litre blood
How are WBCs categorised and what is a good way of remembering this?
- characterised into granulocytes and agranulocytes
- those that end in ‘phil’ are granulocytes and those that end in ‘cyte’ are agranulocytes
What are the granulocytes?
- Neutrophils
- Eosinophils
- Basophils
What are the agranulocytes?
- lymphocytes
- monocytes
What is the RBC: platelet: WBC ratio in normal blood?
700:40:1
How much of the WBC count do neutrophils take up?
50-70% - most abundant
What is the structure of neutrophils?
- 9-15um diameter
- Distinctive nucleus, 2-5 lobes, granular cytoplasm
- Stain cytoplasm purple
- Variability in nuclear lobe
What is the function of neutrophils?
- First line of defence against bacterial infection
- Phagocytic
- Very Mobile
- Circulate in blood for approx. 10 hours
- only survive 30 minutes after performing phagocytosis
- Major constituent of pus (once dead)
- Also produces highly reactive, destructive chemical agents including hydrogen peroxide and superoxide anions which can kill bacteria
How much of the WBC count do eosinophils take up?
2-4%
What is the structure of Eosinophils?
- 10-12um in diameter
- Bilobular nucleus
What’s the function of eosinophils?
- Circulate in blood approximately 8-12 hours migrate to tissues
- Survive approximately 1-3 days
- Release toxic compounds, e.g. NO and cytoxic enzymes
- Allergies, asthma (increased number of eosinophils are an indicator of them)
- Combat parasitic infections
- Also attack bacteria, protozoa, debris