Notes on hematopoietic system for medical students

1. Hematopoietic system

7. INTRODUCTION
Blood is a liquid connective tissue
It is 3 to 4 times more viscous than H2O and denser
Its temperature is slightly higher 38˚C
Slightly alkaline with a ph of 7,35-7,45
It consttitute 8% of body’s weight
It has volume of 5-6L in males and 4-5L in females
It color varies with its oxygen concentration

8. Functions of blood
Transportation of respiratory gases
waste product nutrients and
hormones
Regulation of body temparature and
pH
Protection through blood clotting ,
phagocytes and antibodies

9. Components of Blood
Blood has two components:
 (1) blood plasma, a watery liquid extracellular
matrix that contains dissolved substances (55%)
(2) formed elements, which are cells and cell
fragments. (45%)
99% of the formed elements are red blood cells
(RBCs) and white blood cells (WBCs)
platelets occupy less than 1% of the formed
elements.

11. Blood Plasma
Blood plasma is about 91.5% water
and 8.5% solutes, most of Which are
proteins. (plasma proteins)
NB: serum is plasma without plasma
proteins

12. Blood Plasma (2)
Plasma proteins: they are produced by the liver, they
are
1.Albumin (60%) it is the most abundant protein in
blood and the smallest it functions in transport And
they also maintain oncotic pressure
2.Globulins(36%) functions in defense ( gamma
globulins are produced by B lymphocytes)
3.Fibrinogen(4%) for blood clotting
4.Prothrombin……..

13. Blood Plasma (3)
MINERAL SALTS : they are Ca, Na, K, Mg, HCO3-, Cl-,
etc. they help maintain the osmotic pressure while
water maintain hydrostatic pressure
NUTRIENTS; plasma contains products of digestion
such as glucose, fatty acids and vitamins
Other substances like hormones and enzymes
Waste products like urea, uric acid, creatinine,
bilirubin

14. Formed elements
I. Red blood cells
II. White blood cells
A. Granular leukocytes
1. Neutrophils
2. Eosinophils
3. Basophils
B. Agranular leukocytes
1. T and B lymphocytes and natural killer (NK) cells
2. Monocytes
III. Platelets

16. Formed elements
They are formed by a processe known as hematopoiesis
from cells called hematopoietic stem cells (pluripotent
cells) Q
pluripotent because give rise to various blast cell which
them selfs are precosor cells
Proerythroblasts →RBCs
Myeloblasts → neutrophils
Lymphoblasts → lymphocytes
Megacaryoblasts → platelets
Monoblasts → monocytes

18. HEMATOPOIETIC TISSUE
Yolk sac: it produces RBCs from the first to
the second month of intra uterine life
Liver and spleen and lymphoid node;
produces RBCs from the 3rd to the 6th
month of IUL
Red bone marrow; from the 4th month of
IUL to adulthood ( flat bones and long bones
)

19. HEMATOPOIETIC TISSUE (2)
 hematopoiesis is stimulated by
EPO produced by the kidneys
Thrombopoietin secreted by the liver
and stimulate the formation of platelets
Cytokins stimulates WBCs production

20. RED BLOOD CELLS (erythrocytes)
RBCs are biconcave discs with a diameter of 7–8
µm
It contains hemoglobin, which is a pigment that
gives blood its red color.
adult male has about 5.4 million RBCs/µL of
blood and adult female has about 4.8 million.
RBCs lack mitochondria and generate ATP
anaerobically

21. RED BLOOD CELLS
HEMOGLOBIN; Each RBC contains about 280 million
hemoglobin molecules.
It is made up of heme and four polypeptide
chains(globin)
each of which contain 4 Fe2+ that can bind 4 O2
We have 4 types of Hb : HbA(2 2 ), HbF(2 2) HbE (2 2 )
HbA2
After 120 days RBCs are destroyed by fixed phagocytic
macrophages in the spleen and liver.

24. WHITE BLOOD CELLS
They are divided into two principal
group ; granulocytes (cytoplasm
has granules) and agranulocytes (
granules in the cytoplasm)
They all together function in defence

26. Granulocytes
They are neutrophils Eosinophils Basophils ( NEB )
NEUTROPHILS (70%) their nucleus has 3 lobes their
cytoplasmic granules appear light purple. they are
phagocytes and the first to arrive the site of
infection
they have 2 lobes that contain heparin that helps in
blood clotting and also secrete histamin

28. Granulocytes (2)
EOSINOPHILS (1-2%) ; nucleus has two
lobes their granules stain red. Their granules
secrete histamine which intervens in allergic
reactions they also fight effectively against
parasitic infections
BASOPHILS; (0-0.5%) their granules are
deep blue

29. Agranulocytes
They include monocytes and
lymphocytes
MONOCYTES; (4%) they are the largest
blood cells they leave the blood stream
to become macrophages that
phagocytize bacterias, dead cells and
some debris in tissues

30. Agranulocytes (2)
LYMPHOCYTES(24%): the are produced by
the RBM and some lymphoid organs; the
major types are T and B lymphocytes
 B cells are produced and develop in the
bone marrow and secret antibodies
T cells are produced in the bone marrow
and get matured in the thymus they destroy
tumor cells transplants and micro
organisms

31. Platelets
These are cells fragments and lack a
nucleus they are capable of amoeboïd
movement like lymphocytes
They may live about 10 days
They play in role in blood clotting

33. Hematopoietic system ii
T.D.POINCARÉ

34. Hemostasis
t

35. Hemostasis
is a sequence of responses that
stops bleeding.
Three mechanisms reduce blood
loss after an injury: (1) vascular
spasm, (2) platelet plug formation,
and (3) blood clotting

36. Vascular Spasm
It is the contraction of blood vessel
smooth muscles After damage
This reduces blood loss for several
minutes to several hours
It is induced by pain receptors and
substances secreted by the damage cells

37. Platelet Plug Formation
For a platelet plug to be form it takes 3 steps
1. platelet adhesion: platelets contact and stick to
parts of a damaged blood vessel
2.platelet release reaction; platelets become
activated, and their characteristics change
dramatically they secret Serotonin and
thromboxane A2 function as vasoconstrictors.
3.Platelet aggregation.

41. Blood Clotting
clotting or coagulation, is a series of
chemical reactions that culminates in
formation of fibrin threads.
Clotting involves several substances
known as clotting factors. Most clotting
factors are identified by Roman numerals

43. Mnemonics for CFs
Foolish people try
climbing long slopes
after christmas, some
people have fallen

44. Blood Clotting (2)
Two pathways, called the extrinsic pathway
and the intrinsic pathway, lead to the
formation of prothrombinase.
Once prothrombinase is formed, the steps
involved in the next two stages of clotting
are the same for both the extrinsic and
intrinsic pathways ( common pathway)

46. Blood Clotting (3)
Prothrombinase converts
prothrombin (a plasma protein formed
by the liver) into the enzyme thrombin.
Thrombin converts soluble fibrinogen
into insoluble fibrin. Fibrin forms the
threads of the clot.

50. Role of Vitamin K in Clotting
it is required for the synthesis of four
clotting factors.
They are II VII IX X (1972)
People suffering from vitamin K
deficiency often experience
uncontrolled bleeding

51. fibrinolysis
Dissolution of a clot is called fibrinolysis
It is done by an inactive plasma enzyme
called plasminogen when it is converted
to plasmin
The activation is done by thrombin,
activated factor XII, and tissue
plasminogen activator (t-PA),

52. BLOOD GROUPS

53. ABO Blood Group
The surfaces of RBCs contain antigens
composed of glycoproteins and
glycolipids , called agglutinogens
Blood plasma usually contains
antibodies called agglutinins that react
with the A or B antigens if the two are
mixed.

58. Rh Blood Group
People whose RBCs have Rh antigens are
designated Rh+ (Rh positive); those who lack Rh
antigens are designated Rh- (Rh negative)
Normally, blood plasma does not contain anti-Rh
antibodies. They are synthesized only after a first
transfusion (Rh- receives from Rh+)
If a second transfusion is given …………..

60. Rh Blood Group
People whose RBCs have Rh antigens are
designated Rh+ (Rh positive); those who lack Rh
antigens are designated Rh- (Rh negative)
Normally, blood plasma does not contain anti-Rh
antibodies. They are synthesized only after a first
transfusion (Rh- receives from Rh+)
If a second transfusion is given …………..

65. Some disorders
Anemia
1.Irondeficiency anemia.
2.Megaloblastic anemia(insuff FA).
3.pernicious anemia( insuff B12 absobtion).
4.hemorrhagic anemia.
5.hemolytic anemia.
6.aplastic anemia( destruction of BM).

66. Some disorders (2)
Sickle-Cell Disease
Hemophilia
Leukemia
Cyanosis
Jaundice

69. Some disorders (2)
Sickle-Cell Disease
Hemophilia
Leukemia
Cyanosis
Jaundice

72. for your
kind
attention