Blood is a connective tissue composed of cells (red blood cells, white blood cells, and platelets) and plasma, with an average volume of about 5 liters in adults. Its primary functions include transporting gases, nutrients, and waste; providing defense against infections; and facilitating hemostasis to prevent blood loss. Blood components can be categorized into red blood cells, which carry oxygen and carbon dioxide; white blood cells, which defend against pathogens; and platelets, which aid in clotting.

1. Blood Physiology

2. Blood
 Blood is a type of connective tissues.
 It consist of :
1- Cells (cellular part)
2- plasma (fluid part )
The cells are:
 Red blood cells (RBCs) or erythrocytes.
 White blood cells (WBCs) or leukocytes.
 Platelets or thrombocytes.

4.  Volume of blood is about 5 litters in an
average adult male.
 8% of the total body weight.
 Volume of plasma is about 3.5 L (5% of
total body weight)
 Formation in blood :
In adults : mainly in the bone marrow

5. Hematopoiesis (formation of blood)

6. The packed cell volume(PCV)
 The cells in the blood can be separated by
centrifugation.
 The percentage of cells in blood is called
the packed cell volume (PCV) or the
hematocrit.
 Most of these cells are RBCs (99.9%).
Normal values : - male 40-50%
- Females 37-47%

7.  Low PCV indicate
anemia
 High PCV indicates
polycythemia.

9. Functions of blood
1- Transport of :
 Gases (e.g. oxygen & carbon dioxide).
 Nutrients (e.g. glucose, amino acids & free
fatty acids ).
 Waste products (e.g. urea & uric acid).
 Hormones (e.g. insulin & cortisol)

10. 2- Defense by WBCs and antibodies .
3- Hemostasis:
- prevention of blood loss & maintenance
of blood in fluid state.

11. Characteristics of RBCs:-
 Shape: biconcave disks.
 Diameter:7.5 micrometer.
 Content: no nucleus & no organelles.
 Life span= 120 days
 Each cell contains hemoglobin
 RBCs count:
male 4.8 – 5.8 million/mm³.
female 4.2 – 5.2 million/mm³
Red blood cell (Erythrocyte)

13. Functions of RBCs
 Transport oxygen.
 Transport carbon dioxide.
 Contains buffers(Hemoglobin) to
control pH.

14. Control of Erythropoiesis (formation of
RBCs)
 Normal erythropoiesis requires:
1- normal bone marrow
2- certain hormones (erythropoietin)
3- nutrients(e.g. iron, folic acid, and
vitamins)

15. Hemoglobin(Hb)
 The red pigment within the RBCs.
 Its concentration in the blood :
 14-16 g/dl in adult males
 13-15 g/dl in adult females.
 18-20 g/dl in neonates.

16. Functions of Hb
 Carries 98% of oxygen in the blood.
 Carries some carbon dioxide.
 Buffer.

17. Normal types of Hb
1-Hb A:-
 Adult Hb = 98% of all Hb in adults.
2- Hb A2:-
 Adult Hb = 2 % of all Hb in adults.
3- Hb F :-
 Fetal Hb
 Replaced by Hb A at 6 months after birth.
 Hb F has higher affinity to oxygen than Hb A.
4- HbA1c:-
 Subtype of Hb A, bound with the glucose.
 Its excess indicates poor control of diabetes
mellitus.

18. Abnormal types of Hb
Hb S :-
 Sickle cell Hb.
 It is a Hb A but the amino acid number 6 in
beta chain (glutamic acid) is replaced by
(valine).

19. Anemia
The definition :-
 State of reduction in Hb concentration
below the normal range.
The symptoms :-
 Headache.
 Weakness & fatigability.
 Palpitation.
 Pallor in the skin & mucous membranes.

20. Causes of anemia :-
1- Decreased production :
 Bone marrow diseases e.g. tumors.
 Lack of nutrients e.g. iron, vitamin B12 and
folic acid
2- Increased destruction :-
 as in sickle cell and malaria
3- Blood loss

21. White blood cell (leucocytes)
(WBCs )
 The motile units in the blood that
protect the body against invaders
 A larger blood cell.
 Contains nucleus, mitochondria.
 Normal count: 4000-11000/mm³

22. Functions of WBCs
 Defense against :
1- Bacterial infections
2- Parasitic infections
3- Viral infections
4- Tumors

23. Classification
Are two types:-
1-Granulocytes
2-A granulocytes

24. Granulocytes
 Have granulated cytoplasm
 Polysegmented nucleus
 Shorter life span (Hours)

25. Types of Granulocytes
 Neutrophils:
◦ the granules react with basic and acidic
dyes
 Eosinophils (Acidophils):
◦ the granules react with acidic dyes
(eosin)
 Basophils:
◦ the granules react with basic dyes

26. Neutrophil:
 Constitute 50-70% of total WBCs
 Nucleus: segmented (3-5 lobes)
 Cytoplasm: granulated
 Granules: purple
 functions:-
phagocytosis of bacteria
 Increased in: Acute bacterial infections

27. Eosinophil :
 Constitute 1-4% of total WBCs
 Nucleus: segmented (2 lobes)
 Cytoplasm: granulated
 Granules: Red
 Increased in:
parasitic infections

28. Basophils
 Constitute 0-0.4% of total WBCs
 Nucleus: segmented (hidden by the granules)
 Large cytoplasmic granules contain heparin,
histamine
 Increased in allergic reactions

29. Agranulocytes
 Generally have no granules in the
cytoplasm
 Have one nucleus (not segmented)
Types of Agranulocytes:
Monocytes Lymphocytes

30. Monocyte
 Larger diameter than other types of
WBCs
 Constitute 2-8% of total WBCs
 Nucleus: kidney shape
 Cytoplasm: no granules
 Function: macrophages
(phagocytosis)

31. Lymphocyte
 Constitute 20-40% of total
WBCs
 Nucleus: rounded
 Cytoplasm: no granules
 Function:
Responsible for immunity.
 T lymphocytes: cellular immunity
 B lymphocytes: humoral immunity

32. Hemostasis

33. HEMOSTASIS
Definition :
 Prevention of blood loss by arrest of bleeding
and maintenance of blood in fluid state.
Mechanisms of hemostasis:
 Vasospasm (vasoconstriction)
 Formation of platelet plug
 Formation of blood clot ( coagulation).
 Fibrinolysis or fibrous tissues formation.

34. Platelets
 Small cells (2-4 micrometer in diameter).
 Count : 150.ooo-400.ooo/mm3.
 They circulate in the blood in an inactive
state

37. Blood grouping
 Definition:
 is classification of blood based on the
presence or absence of inherited
antigen on the surface of red blood
cells (RBCs).

38. Importance :
1-Blood transfusion
2-Exclusion of paternity
Blood systems:
1- ABO system
2- Rh system (Rhesus)

39. ABO system

41.  People with blood group (O⁻) are
called
"universal donors"
 and people with blood group (AB⁺) are
called
"universal receivers."

42. Rhesus Factor (Rh Factor )
 Besides the ABO system, a person
can be either…
 Rh positive
(there is antigen D)
 Rh negative
(No antigen D)