Haematology: WBC Flashcards
What are the 5 white blood cells?
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
- Lymphocytes
What are neutrophils?
- If the nucleus is lobed, they are mature neutrophils
- If the nucleus has a band, they are young neutrophils
- Fine pink granules
- Function: phagocytosis
What are eosinophils?
- Lobed nucleus
- Big granules
- Function: fight parasites
What are basophils?
- Lobed nucleus
- Purple granules
- Function: Release histamines, which stimulate inflammation
What are mast cells?
- Round/oval nucleus
- Rarely seen in a blood smear
- Numerous purple cytoplasmic granules
- Seen in allergic disease
What are monocytes?
- Large cells
- Nucleus pale and very variable shape
- May have vacuoles in cytoplasm
- Function: Remove debris and stimulate healing
What are lymphocytes?
- No granules in cytoplasm
- If reacting, cytoplasm becomes dark blue
- Function: T and B cell stimulation
What is the neutrophil life cycle?
- Produced in bone marrow (takes a week)
- Enters blood (for only 12 hours)
- Marginate (in capillary to wait if needed; this will take 2-5 days)
What happens to neutrophils in the blood?
- Band neutrophils become segmentated neutrophils, where the nuclues divides into 3-5 lobes
- These then become hyper-segmented, where the nucleus divides further into over 6 lobes
What causes a decrease in pancytopenia?
- All blood cells
- Severe myelosuppression
What causes a decrease in panleucopenia?
- WBC
What causes an increase in neutrophilia?
- Stress
- Steroid inflammation
What causes a decrease in neutropenia?
- Severe infection
- Decreased BM production due to chemotherapy
What causes an increase in eosinophils?
- Parasitism
- Allergy
What causes an increase in lymphocytosis?
- Lymphoproliferative disease e.g., lymphoid leukaemia
What causes a decrease in lymphopenia?
- Viral infection
What causes an increase in monocytosis?
- Inflammation
What do increase WBCC show?
- Infection
- Neutrophilia
- Neoplasia
- Allergy or parasitism
- Lymphoprofilerative disease
What do increased neutrophils (left shift) show?
- Increased numbers of band neutrophils, which cause inflammation, so cytokines are released, which stimulate BM to increase production
What do increased neutrophils (right shift) show?
- Increased number of hyper-segmented neutrophils stimulate adrenaline or cortisol, which stop cells marginating
How does a toxic change happen in neutrophils?
- These are abnormal neutrophils (abnormal vacuoles and granules), which are released by the BM, as struggling to keep up with demand
What is excitement or fear leucocytosis?
- Excitement/fear releases adrenaline, which triggers a right shift, which triggers spleen contraction and lymphocytosis
What is stress leucocytosis?
- Stress releases cortisol, which triggers a right shift, which triggers lymphopenia
What is inflammatory leucocytosis?
- Inflammation/infection releases cytokines, which triggers a left shift, which can causes toxic damage at rushed production
What do decreased WBCC show?
- BM can’t kepp up with the migration of cells to where they are needed
- Overwhelming bacterial infection resulting in neutropenia
- Viral infectionresulting in lymphopenia
- Lymphoprofilerative disorders
- Cytotoxic drug
- Oestrogen supplementation
- Irradiation
- BM infection
What are platelets?
- Small biconcave discs
- No nucleus
- Pink granules
How do platelets form?
- Thrombocytes bud off to form megakaryocytes in the BM
- Stimulated by thrombopoietin from liver and kidney
What happens when platelets are activated?
- Become small binconvex discs
- Become stellate and stick to each other to make a plug and damage vessel
- Stick to collagen via the von Willebrand factor
What are the 3 steps of haemostasis?
- Vascular spasm
- Platelet plug formation
- Coagulation
What happens in vascular spasm?
- Smooth muscle contracts causing vasoconstriction
What happens in platelet plug formation?
- Injury to lining of vessel exposes collagen fibres and platelets adhere. Platelets release chemicals that make nearby sticky, which causes a plug
What happens in coagulation?
- Fibrin forms a mesh that traps RBCs and platelets, forming a clot via a extrinsic (blood vessel ruptures) or intrinsic pathway (damage blood vessel exposes collagen)
How are clotting factors produced?
- Made in the liver; require vitamin K
What are clinical signs of a clotting factor deficiency?
- Delayed bleeding
- Large bruises (ecchymoses)
Name some platelet disorders
- Thrombocytopenia
- Thrombocytopathia
- Von Willebrand disorder
What is Thrombocytopenia?
- Decreased production in platelets caused by a BM disorder
- Increased loss/use of platelets caused by haemorrhage, enlarged spleen and immune mediated thrombocytopenia
How is haemostasis assessed?
- Bleeding time
- Clot retraction
