1. BLOOD

2. Formed Elements of Blood
In adults about 5 liter of blood contributes 7-8 % to the body weight.
The cellular element composed of erythrocytes (red blood cells), leucocytes (white blood cells), and platelets.
Plasma is a viscous, translucent, and yellowish fluid composed of water (90%), proteins(7%), organic salts (1%), and organic compound (2%) such as amino acids, lipids, and vitamins.

3. Functions
Erythrocytes and blood platelets perform their functions inside the blood vessels
leukocytes reside temporarily in the blood and can leave the blood stream through the walls of capillaries and venules and enter either connective or lymphoid tissues.

4. Composition of plasma Plasma proteins composed of:-
- Albumins (bulk): bind and transport.
- Globulins: alpha, beta and gamma globulins.
- Lipoproteins
- Blood coagulation proteins: prothrombin, fibrinogen which gives rise to fibrin.

5. celluar Elements of Blood
Erythrocytes (RBC)
Leukocytes (WBC)
Granulocytes
Agranulocytes
Platelets (Thrombocytes)

7. ERYTHROCYTE 4.5 -5 million /mm3
Mature cell has no nucleus, or organelles.
They contain hemoglobin, which fills almost the entire cytoplasm
Fetal erythrocytes (up to the 4th month of gestation) are larger than "adult" erythrocytes, and they are nucleated.
Erythrocytes are remarkably elastic and can withstand deformation.
Function :Transports O2 and CO2.

8. RBC Readily deform and pass through capillaries. Lifespan is 120 days.
Removed by spleen and liver.
Reticulocytes are immature RBCs released from bone marrow; normally estimated ~ 1% of circulating RBCs.

9. TEM RBC
Reticulocyte with a
few organelles.
RBC in capillary

11. White blood cells (WBC) or leucocytes
Leukocytes can be subdivided into:
granular leukocytes (neutrophils, basophils and
eosiniphils)
2. non-granular leukocytes (monocytes and lymphocytes).
In healthy individuals the total number of circulating leukocyte is about /mm3. this number can increase in infection.

12. The frequencies of WBC · ~ 60% neutrophils (50% - 70%)
· ~ 40% lymphocytes (20% - 40%)
· ~ 5% monocytes (1% - 9%)
· ~ 4% eosinophils (>0% - 5%)
· ~ 0.5-1% basophils (>0% - 2%)
A larger than usual number of neutrophils (neutrophilia) would indicate e.g.an acute or chronic infection.
The number of basophils and eosinophils may increase (eosinophilia or basophilia) as a consequence of e.g. allergic disorders.

14. Granular Leukocytes
Granular leukocytes are all approximately the same size (12-15 μm in diameter).
Their nuclei are lobulated and nucleoli cannot be seen.
The number of nuclear lobes varies according to cell type. All granulocytes are motile.
The term granulocyte refers to the presence of granules
in the cytoplasm of these cells.
The granules correspond to secretory vesicles and lysosomes.

15. 1. Neutrophil Characteristics
60-70% of leukocytes
diameter µm
nucleus 2-8 lobes
The number of lobes increases with cell age
'drumstick' on lobe in 3% of neutrophils in females (Barr body)

16. NEUTROPHIL

17. Neutrophils, mature and almost!

18. Function Neutrophils play a central role in inflammatory processes.
Neutrophils are the first wave of cells invading infection
Receptors in their plasma membrane allow them to recognize foreign bodies, e.g. bacteria, and tissue debris, which begin to phagocytose and destroy.

19. Neutrophils Movement by pseudopodia. Engulfed bacterium.
Mature and younger
Cells (lobes)

20. Basophil Characteristics
Less than 1% of leukocytes.
Diameter 14 µm.
Nucleus large and bilobed.
Cytoplasm filled with large dark-blue staining granules (basophilic) which may obscure nucleus .

21. Basophil Function: immunological response to parasites.
Contain many mediators of inflammatory response.
Closely related to mast cells. Basophils and mast cells bind to IgE produced in response to allergens.

22. Basophil Bilobed nucleus
Granules (S) contain heparin, leukotrienes, histamine.
Mitochondria, ribosomes, glycogen in cytoplasm.

23. EOSINOPHIL

24. Eosinophil Characteristics
1-5% of leukocytes.
Diameter µm.
slightly larger than neutrophils
Nucleus usually bilobed.
Cytoplasm filled with numerous large eosinophilic (acidophilic) granules which stain pale-pink.

25. Functions of Eosinophils
Phagocytic for antigen-antibody complexes.
Defense against parasites.
Release granules against parasites which are injured by enzymes.
respond to basophils and mast cells.

26. SEM Eosinophil Specific granules (S) stains reddish.
S granules contain many
hydrolytic enzymes.
Contains glycogen, some
mitochondria, rER,
sER.

27. Non-granular leukocytes
1- Monocytes:
- Monocytes are large cells, μm in diameter; represent 2-10 %
white cell count.
Monocytes are highly motile phagocytic cells; i.e. they can migrate into tissues; engulf and destroy tissue debris & foreign material.
Their nucleus less dense than lymphocytes; deeply indented, C-shaped or kidney shaped.

29. Function
Once monocytes enter the connective tissue they differentiate into macrophages that phagocytose microorganisms, tissue debris and the dead neutrophils.

30. 2. Lymphocytes (B and T cells):
Lymphocytes represent 20 to 40% of the differential white cell count.
There are two structural types:
Most small lymphocytes in the blood stream belong to either the group of B-lymphocytes (~5%) or the group of T-lymphocytes (~90%).

31. Cell shape
The cell is rounded with densely stained nucleus, small amount of pale basophilic cytoplasm (seen in EM) more numerous on B lymphocytes than T lymphocytes.
the two groups can not easily be distinguished using routine light or electron microscopy. .

32. Functions
Upon exposure to antigens B-lymphocytes differentiate into antibody producing plasma cells that produce antibodies which directed against foreign antigen.
- T-lymphocytes represent the "cellular arm" of the immune response (cytotoxic T cells) and may attack foreign cells, cancer cells and cells infected by e.g. a virus.

33. Blood platelets (thrombocytes):
-Blood platelets do not contain nucleus
-they are cytoplasmic fragments of very largethrombocyte (megakaryocytes) that are found in the bone marrow.
Their number is 150, ,000/mm3.
They are rounded or oval, biconvex discs, 1.5 to 3.5μm in diameter.
-Different types of vesicles contain either serotonin) or compounds important for blood coagulation
-Serotonin is a potent vasoconstrictor. The release of serotonin from thrombocytes, which adhere to the walls of a damaged vessels,is sufficient to close even small arteries.