1. BLOOD & HAEMOPOIESIS
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2. Objective
The main objective is for you to familiarise with the normal composition of blood.
That will enable you to easily spot changes due to infection or disease; leading to marked changes in some cell types.
You should also become familiar with the development and differentiation of blood cells in haemopoietic tissues.

3. Mammalian blood smears (dog)
Examination of a stained mammalian blood smear.
You should be able to identify most cell types.
Identify cells in the smear.
Erythrocytes.
Platelets.
Neutrophils.
Eosinophils.
Basophils (if and when present).
Lymphocytes.
Monocytes.
You should base your identification on the following characteristics:
The staining characteristics of the cells.
The presence or absence of a nucleus.
The size and shape of the cell and its nucleus.
The presence or the absence of cytoplasmic granules.

4. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Which cells in this blood smear lack a nucleus?
What are the smallest components in this smear?
Which cells in this smear contain granules in their cytoplasm?
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?
The answers to the above questions will follow the next series of pictures.

5. Mammalian blood smears (dog)
Erythrocytes
10 µm

6. Mammalian blood smears (dog)
Platelets
platelets
10 µm

7. Mammalian blood smears (dog)
Neutrophils
10 µm

8. Mammalian blood smears (dog)
Eosinophil (and lymphocyte)
eosinophil
lymphocyte
10 µm

9. Mammalian blood smears (dog)
Lymphocytes
10 µm

10. Mammalian blood smears (dog)
Monocyte (and lymphocyte)
monocyte
lymphocyte
10 µm

11. Mammalian blood smears (dog)
Smudged and distorted blood smear.
Although this smear has distorted cells, it shows well the granules in a smudged and partially ruptured eosinophil.
A large quantity of platelets can also be seen.
platelets
smudged eosinophil
10 µm

12. Mammalian blood smears (human)
Neutrophil
10 µm

13. Mammalian blood smears (human)
Eosinophil
10 µm

14. Mammalian blood smears (human)
Basophil and lymphocyte
basophil
lymphocyte
10 µm

15. Mammalian blood smears (human)
Neutrophils
Platelets
Lymphocyte N P
N : neutrophils L
P : platelets N
L : lymphocyte P
10 µm

16. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Which cells in this blood smear lack a nucleus?
What are the smallest components in this smear?
Which cells in this smear contain granules in their cytoplasm?
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

17. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
What are the smallest components in this smear?
Which cells in this smear contain granules in their cytoplasm?
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

18. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Which cells in this smear contain granules in their cytoplasm?
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

19. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Platelets.
Which cells in this smear contain granules in their cytoplasm?
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

20. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Platelets.
Which cells in this smear contain granules in their cytoplasm?
Neutrophils, Eosinophils and Basophils (granulocytes).
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

21. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Platelets.
Which cells in this smear contain granules in their cytoplasm?
Neutrophils, Eosinophils and Basophils (granulocytes).
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

22. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Platelets.
Which cells in this smear contain granules in their cytoplasm?
Neutrophils, Eosinophils and Basophils (granulocytes).
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
The Neutrophil with 3-5 lobes.
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
In which cell is the nucleus most obviously eccentrically placed?

23. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Platelets.
Which cells in this smear contain granules in their cytoplasm?
Neutrophils, Eosinophils and Basophils (granulocytes).
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
The Neutrophil with 3-5 lobes.
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
The Lymphocyte.
In which cell is the nucleus most obviously eccentrically placed?

24. Mammalian blood smears (dog)
Is there any difference in the colour of the cytoplasm of these cells e.g. do they all stain pink or blue?
Cytoplasm of erythrocytes stains pink, that of leucocytes is blue-grey with cytoplasmic granules staining grey/pink, red/pink or blue/purple.
Which cells in this blood smear lack a nucleus?
Erythrocytes and platelets.
What are the smallest components in this smear?
Platelets.
Which cells in this smear contain granules in their cytoplasm?
Neutrophils, Eosinophils and Basophils (granulocytes).
In which cells are the nuclei lobed?
Which cells show the most lobed nucleus?
The Neutrophil with 3-5 lobes.
Which cell has little cytoplasm with most of the cell space taken up by the nucleus?
The Lymphocyte.
In which cell is the nucleus most obviously eccentrically placed?
The Monocyte.

25. Avian blood smears Examination of a stained avian blood smear.
You should be able to identify most cell types.
Erythrocytes Avian erythrocytes are elongated cells with an oval nucleus.
Thrombocytes Nucleated cells, smaller than the erythrocytes,
function as platelets.
Lymphocytes.
Monocytes.
Heterophils Eosinophilic rod or spindle shaped granules.
(the most numerous of the granulocytes)
Eosinophils Eosinophilic granules round.
Basophils More numerous than in mammals, nucleus often without lobes.

26. Avian blood smears
Erythrocytes
10 µm

27. Avian blood smears
Thrombocytes
10 µm

28. Avian blood smears
Heterophils
10 µm

29. Lymphocyte, heterophils and thrombocytes
Avian blood smears
Lymphocyte, heterophils and thrombocytes
lymphocyte
thrombocytes
heterophils
10 µm

30. Avian blood smears
Basophil
10 µm

31. Avian blood smears
What is the major difference between the mammalian and the avian blood smears?
Do any cells in the avian smear lack a nucleus?
How does the morphology of erythrocytes and thrombocytes vary in mammalian and avian blood?

32. Avian blood smears
What is the major difference between the mammalian and the avian blood smears?
Erythrocytes and platelets are nucleated. Platelets much larger than mammalian.
Do any cells in the avian smear lack a nucleus?
How does the morphology of erythrocytes and thrombocytes vary in mammalian and avian blood?

33. Avian blood smears
What is the major difference between the mammalian and the avian blood smears?
Erythrocytes and platelets are nucleated. Platelets much larger than mammalian.
Do any cells in the avian smear lack a nucleus?
No.
How does the morphology of erythrocytes and thrombocytes vary in mammalian and avian blood?

34. Avian blood smears
What is the major difference between the mammalian and the avian blood smears?
Erythrocytes and platelets are nucleated. Platelets much larger than mammalian.
Do any cells in the avian smear lack a nucleus?
No.
How does the morphology of erythrocytes and thrombocytes vary in mammalian and avian blood?
Erythrocytes
Mammalian : A biconcave flattened disc in the mature state lacking a
nucleus and cell organelles.
Avian : Elongated cells with an oval nucleus.
Erythrocyte size in both mammalian and avian blood is species dependant.

35. Avian blood smears
What is the major difference between the mammalian and the avian blood smears?
Erythrocytes and platelets are nucleated. Platelets much larger than mammalian.
Do any cells in the avian smear lack a nucleus?
No.
How does the morphology of erythrocytes and thrombocytes vary in mammalian and avian blood?
Erythrocytes
Mammalian : A biconcave flattened disc in the mature state lacking a
nucleus and cell organelles.
Avian : Elongated cells with an oval nucleus.
Erythrocyte size in both mammalian and avian blood is species dependant.
Thrombocytes
Mammalian : Cell fragments bounded by membranes, from the
megakaryocytes found in the bone marrow and spleen.
Avian : Nucleated cells, smaller than the erythrocytes with a
more rounded nucleus.

36. Snake blood (from lung tissue)
Reptilian blood comprises
similar cellular components
to avian blood.
Erythrocytes are elongated,
nucleated cells.
Size is variable between species.
Shown here a group of mainly
erythrocytes seen in a section
of snake lung tissue.
(this slide is not available in the class)
25 µm

37. SLIDE 192 Bone marrow Haemopoiesis
You will observe blood cells at different stages of development and differentiation.
It may be difficult to identify different cells with certainty until they approach later stages of differentiation e.g. accumulation of cytoplasmic granules that also impart specific staining characteristics and the development of lobulated nuclei.
The easiest cells to identify in these sections are the megakaryocytes very large cells with lobulated nuclei.
You should see many granulocytes showing different levels of nuclear lobulation.
250 µm

38. SLIDE 192 Bone marrow Haemopoiesis
You will observe blood cells at different stages of development and differentiation.
It may be difficult to identify different cells with certainty until they approach later stages of differentiation e.g. accumulation of cytoplasmic granules that also impart specific staining characteristics and the development of lobulated nuclei.
The easiest cells to identify in these sections are the megakaryocytes very large cells with lobulated nuclei.
You should see many granulocytes showing different levels of nuclear lobulation.
Low magnification view of a
portion of bone marrow.
megakaryocytes can be seen.
250 µm

39. SLIDE 192 Bone marrow Haemopoiesis
The easiest cells to identify in these sections are the megakaryocytes very large cells with lobulated nuclei.
50 µm

40. SLIDE 192 Bone marrow Haemopoiesis
The easiest cells to identify in these sections are the megakaryocytes very large cells with lobulated nuclei.
megakaryocytes
50 µm

41. SLIDE 192 Bone marrow Haemopoiesis
Megakaryocytes and developing erythrocytes and granulocytes.
developing
erythroblasts
25 µm

42. SLIDE 192 Bone marrow Haemopoiesis
The lobed nucleus of the megakaryocyte is clear in the right hand picture.
Eosinophilic staining cells arrowed.
25 µm

43. SLIDE 192 Bone marrow Haemopoiesis
The lobed nucleus of the megakaryocyte is clear in the right hand picture.
Eosinophilic staining cells arrowed.
mitotic figure
lobed nuclei of
developing
granulocytes
25 µm

44. SLIDE 22 Foetal liver Haemopoiesis (cat) SLIDE 49 Adult liver (pig)
Foetal Adult
1.0 mm

45. SLIDE 22 Foetal liver Haemopoiesis (cat) SLIDE 49 Adult liver (pig)
Foetal with haemopoietic tissue Adult with clearly defined cords of hepatocytes
and sinusoids
C : central vein C C
100 µm

46. SLIDE 22 Foetal liver Haemopoiesis (cat)
Haemopoietic tissue in the foetal liver.
central vein
25 µm

47. SLIDE 148 Foetal spleen Haemopoiesis (cat)
General low magnification view of slide.
1.0 mm

48. SLIDE 148 Foetal spleen Haemopoiesis (cat)
Again the giant megakaryocytes (arrowed) are the most prominent cells.
blood vessel
50 µm

49. SLIDE 148 Foetal spleen Haemopoiesis (cat)
Maturing cells become more recognisable as lobed nuclei develop or cytoplasmic granules with specific staining characteristics appear.
25 µm

50. SLIDE 148 Foetal spleen Haemopoiesis (cat)
Maturing cells become more recognisable as lobed nuclei develop or cytoplasmic granules with specific staining characteristics appear.
megakaryocytes
25 µm

51. Lecturer. Dr. Tej Dhoot. First Year Histology. 004
Lecturer. Dr.Tej Dhoot. First Year Histology Blood & Haemopoiesis. J. Bredl Histology Slides And Stains. Tanya Hopcroft Compressed version 2006, 2007.