ANSWERS

1. What are red blood cells also collectively known as?
   Erythrocytes. Adult erythrocytes are non-nucleated bi-concave discs, which are a pale green/yellow when unstained. NB. Birds have nucleated erythrocytes.
2. What are white blood cells also collectively known as?
   Leukocytes.
3. What are platelets also known as?
   Thrombocytes.
4. What is polychromasia?
   Differing intensity of staining.
5. What is crenation?
   Cells showing irregular margins due to shrinkage. This is a fault usually associated with the air drying of blood films being too slow.
6. What are Howell Jolly bodies? State 2 conditions in which they might be seen.
   Basophilic nuclear remnants seen as the nucleated red blood cells (NRBCs) change to young erythrocytes. They are found in response to anaemia and splenic disorders.
7. What are rouleaux?
   Arrangements of red cells in stacks associated with an increase of fibrinogen or globulin concentration in the blood. This condition is normal in horses, but not in cats and dogs.
8. What are reticulocytes?
   Immature red blood cells with no nucleus. They occur when the cell is completely haemoglobinised and the small dense nucleus is extruded, leaving a grey/blue or polychromatic cell with a reticular structure, which stains blue with supravital stains. After 12 days, the polychromasia is lost and the cell becomes an adult erythrocyte.
9. What are target cells, and when might they be seen?
   Red blood cells with a central rounded area of haemoglobin surrounded by a clear zone. A dense ring of haemoglobin is found around the perimeter of the cell as a result of increased membrane or decreased volume. This type of cell may be found in cases of non-regenerative anaemia.
10. What term describes varying sizes of red blood cells?
    Anisocytosis.
11. What is meant by PCV?
    PCV is an abbreviation for the packed cell volume. It is a measurement of the percentage of red blood cells.
12. What conditions may result in an increased PCV?
    • Dehydration.
    • Diabetes insipidus.
13. What conditions may result in a decreased PCV?
    • Anaemia.
    • Haemorrhage.
    • Hypovolaemic shock.
14. List the types of white blood cells.
    • Neutrophils.
    • Eosinophils.
    • Basophils.
    • Lymphocytes.
    • Monocytes.
    • Platelets.
15. What suffix generally means an increase in the usual number of cells?
    -osis or -ilia. e.g. Leukocytosis means an increase in the number of white blood cells. This condition may be present in cases of infection or immunosupression.
16. What suffix generally means in a decrease in the usual number of cells?
    -paenia; e.g. Leukopaenia means a lack of white blood cells. In Panleukopaenia, every type of white blood cell is depressed. This may be resultant of stress, infection or neoplasia.
17. What is meant by polycythaemia?
    An increase in the number of platelets; also known as thrombocytosis.
18. Describe the role of lymphocytes.
    Lymphocytes play an important protective role, and are associated with the production of antibodies. They also recognise foreign substances such as bacteria, virus and abnormal cells resultant of autoimmune conditions.
19. Describe the role of monocytes.
    Monocytes are large white cells involved in the repair of damaged blood vessels. They adhere to damage and to each other to plug leaks, and are involved in coagulation to produce fibrin.
20. Give 2 examples of conditions that may result in eosinophilia.
    • Parasitic infestation.
    • Allergy.
21. Give 2 examples of conditions that may result in eosinopaenia.
    • Steroid usage.
    • Cushings disease.
22. Which cells are also known as granulocytes?
    Eosinophils, neutrophils and basophils, since they contain granules within their cytoplasm.
23. What conditions may result in neutrophilia?
    • Infection.
    • Inflammation.
    • Stress.
    • Steroids.
24. What cell type may increase in cases of chronic tissue damage or myeloid leukaemias?
    Basophils.
25. State the normal red and white cell count ranges in dogs and cats.
    • RBC Count - dogs = 5.5 - 8.5 x 10 to the power of 12/L.
    • RBC Count - cats = 5 - 10 x 10 to the power of 12/L.
    • WBC Count - dogs = 6 - 17 x 10 to the power of 9/L.
    • WBC Count - cats = 5.5 - 19.5 x 10 to the power of 9/L.