1. Blood and circulatory system
Fawzi A. Babiker
Department of Physiology
E-mail: fawzi.b@hsc.edu.kw
Reference: Human Physiology, by: Stuart Ira Fox; 11th Edition.
2. Blood and Circulation
• Blood
– Composition of Blood
– Hematopoiesis
– Blood types
– Blood clotting
• The Circulation
– Heart structure
– Blood vessels
– Cardiac cycle
– Heart sounds
– Electrical activity of the heart
3. Major Parts of the Circulatory System
- Cardiovascular System:
- Heart
- Blood vessels
- Blood
- Lymphatic System:
- Lymphoid tissue
- Lymph vessels
- Lymph
4. Functions of the circulatory system
Transport:
1- All substances essential for cellular metabolism.
2- Respiratory: oxygen and carbon dioxide.
3- Nutritive: digested food materials.
4- Excretory: metabolic wastes, excess water and ions.
Regulation:
1- Hormonal: from sites of origin to the target tissues.
2- Temperature: diversion of blood between superficial and deeper vessels to
control body temperature.
Protection:
1- Clotting: protection against blood loss.
2- Immune: protection by leukocytes against infectious diseases.
5. Constituents of the blood
Blood is about 8% of the total body weight (5L). It is either arterial blood or
venous blood.
- Blood consists of :
1- Plasma: fluid part of blood contains proteins and electrolytes.
2- Formed elements: blood cells (erythrocytes, white blood cells, platelets).
6. Plasma
Plasma: Straw-colored liquid consists of water and dissolved solutes.
Contains:
- -
1- Electrolytes (ions): Na+, K+, Ca++, Cl , HCO3
2- Organic molecules: Cholestrol, glucose, protein, urea, lactic acid, etc.
3- Hormones: insulin, testosteron, growth hormone, etc.
4- Enzymes: lactate dehydrogenase (LDH),
creatine phosphokinase (CPK), etc.
Plasma
Serum: is similar to plasma only Blood cells
it is formed after blood clotting.
It does not contain fibrinogen.
7. Plasma proteins
Plasma Proteins: 7%-9% of plasma volume.
i- Mainly albumins: account for 60% to 80% of the plasma
proteins (produced by the liver).
ii- Globulins:
iiA- Alpha globulin and Beta globulin: transport lipids- and fats-
dissolved vitamins.
iiB- Gamma globulins: antibodies produced by lymphocytes
(immunity).
iii- Fibrinogen: essential for blood clotting (produced by the
liver).
8. Formed elements of the blood
1- Red blood cells (erythrocytes)
• Most abundant cells of the blood.
• Do not have a nucleus
• Biconcave discs, 7 µm diameter and
2.2 µm thick.
• Contain the protein haemoglobin.
• Haemoglobin carries oxygen
around the body.
• At the centre of the haemoglobin
molecule is an iron atom (heme).
Hemoglobin
9. 2- Platelets
• Called also Thrombocytes.
• The smallest of the formed elements.
• They play an important role in blood clotting.
10. 3- White blood cells WBC (Leukocytes)
• Protective cells of the body. They contain nuclei, move in amoeboid fashion
and they can pass the capillary wall (diapedesis or extravasation).
• They are granular or agranular (non granular).
• Neutrophils are the most abundant type of the granular cells.
Granular Agranular
11. Formation of blood cells
1- Hematopoiesis
Blood cells are formed by a process of hematopoiesis.
During embryogenesis the blood cells are formed from stem cells in the liver.
Soon after birth the stem cells migrate to the bone marrow.
Erythropoiesis is the formation of erythrocytes.
Leukopoiesis is the formation of leukocytes.
Bone marrow
12. A- Erythropoiesis
Erythropoieis = the process of
formation of erythrocytes (RBCs).
This process occurs in the bone
marrow (myeloid tissue).
Bone marrow/myeloid tissue is the
red tissue inside bones.
This process takes 3 days. 2 days in
bone marrow and circulate in the blood
in the 3rd day.
Life span of a blood cell is 120 days after
which it is removed by the phagocytic
cells of spleen, liver and bone marrow.
13. B- Leukopoiesis Leukopoieis = the process of formation
of leukocytes (WBCs).
This process occurs in lymphoid
tissue (lymph nodes, tonsils, spleen
and thymus.)
14. Red blood cells antigens and blood types (ABO system)
There are certain molecules on the
surface of RBCs. These molecules
are called antigens (agglutinogens).
As a part of our body defense
system (immune system) some
WBCs (lymphocytes) secret
proteins called antibodies
(agglutinins).
Every antigen type is coupled with
antibodies secreted by the
lymphocytes act against the other
antigens.
Antibodies can bind to antigens
Destroy RBCs
15. Gentotyping
Here the normal genetic roles of inheritance applies:
A blood group has A antigen which is
shown as IA and antibodies for B.
Blood group B has B antigen which is
shown as IB and antibodies for A.
O has no antigen and is shown as ii.
It has antibodies for A and B.
A person with A may hve got gene A from
each parent (IA IA ) or A from One parent
and O gene from the other (IA i).
A person with group B is (IBIB) or (IBi).
A person with O group has got O gene
from each parent (ii).
A person with AB blood group has got
A gene from one parent and B gene from
the other (IAIB).
16. Genotyping of the blood groups
AO BO
Note that A and B are
dominants and O is always
recessive.
AO AB BO OO
17. Transfusion reactions
Blood from a donor is usually checked by recipient serum.
If the donor is A and the recipient is B then agglutination will occur.
A accepts A and O, but makes clot with B.
- anti A anti B anti D
B accepts B and O, but clots with A.
AB accepts A, B and O and called universal
recipient.
O can be given to A, B and AB and called
universal donor.
O accepts only from O and clots with A and
B because it has antibodies against them.
18. Blood typing Rhesus factor
Another group of antigens found on RBCs surface
is called Rh factor. People who have this antigen on
their RBCs are Rh positive (Rh+). People without Rh
antigen are Rh negative (Rh-).
The Rh factor is very important when Rh- mother gives birth to Rh+ babies.
Rh- Mother Rh- Mother
Next
Anti-Rh+
RBC Delivery Anti-Rh+ pregnancy RBC
Bloods mixes
Rh+ Baby Rh+ Baby
RBC RBC
1st pregnancy 2nd pregnancy
No mixing of blood Mother has antibodies
Against baby RBCs
