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HEAMATOLOGY

Blood: definition, physical characteristics, functions



Definition of blood
Blood is a viscous liquid textures red, another of the forms of connective tissue fills the heart and is going on inside the body through the blood vessels (veins and arteries, and capillaries), and the volume of blood in the body 5-6 liters in an adult as a percentage of 8.7% of body weight, and quantity of blood in the circulatory system (heart and blood vessels) two thirds of the amount found in the whole body, while the remaining one third is stored in the liver, spleen and other parts of the body.
Physical properties of blood
Colour Colour
Red color of blood as a result of the presence of hemoglobin, a compound that gives blood the color and the color varies depending on the type of blood is bright red blood in the arteries as a result of the presence of oxygen and dark red blood in the veins due to the presence of carbon dioxide.
Viscosity Viscosity
Of the viscosity of blood five times the viscosity of water, it is $ 4.7 in men and in women 4.3 and the viscosity of blood depends mainly on the proteins in the plasma protein fibrinogen in particular.
Specific Gravity Specific gravity of blood
Men ranging in between 1.057 - 1.067 in women between 1.051 - 1.061 which is depend on the materials dissolved in the plasma, such as protein and red blood cells.
The degree of acidity of the blood pH
Blood tends to reach the point of saluting the alkaline pH in the blood of the arteries, veins the blood of 7.4 and 7.35.Blood components
Blood components
Blood consists of two important parts:
- Plasma (Plasma) and constitute 55% of the total volume of blood.
- Blood cells (Blood cells) and accounted for 45% of the total volume of blood.
First, plasma ((Plasma
Is a liquid part which swim in blood cells, which are the color of pale yellow and the water is 90% of the total volume of the plasma and this is important if we know that water is good solvent for many substances and particles, and therefore this makes it a compromise effective transfer of material particlesFood dissolved in it, The remaining 10% consists of the following:
- Blood proteins (albumin, globulin, fibrinogen and thrombin).
- Materials such as sugars, fats, vitamins, enzymes and hormones.
- Directorial materials such as urea, creatinine and uric acid.
- Inorganic materials such as potassium, calcium, sodium, chlorine, iron, magnesium and other elements.
Can be obtained on the plasma centrifuge process after the addition of a rod of the clot, where blood cells are deposited.
Second, blood cells ((Blood cells

Blood cells are divided into three sections:
- White blood cells White Blood Cells) WB.C. )
- Red blood cells, Red Blood Cells) RBC).
- Platelets (Blood Platelets).The functions of blood
Functions of Blood
1. Respiratory function Respiratory
Is the transfer of oxygen (O2) from the lungs to the tissues and the expulsion of carbon dioxide (CO2) from the tissues to the lungs.
2. Nutritive food job
Is to transport and distribute food from the gut to all the different tissues of the body.
3. Excretory function directorial
The blood to carry products of tissue metabolism to output devices such as: the transfer of carbon dioxide to the lungs and the transfer of urea to the kidneys.
4. Regulate the temperature of the body Regulation of body temperature
Blood works to distribute heat to all parts of the body heat is transferred quickly from deep tissue to tissue surface and vice versa, so it maintains the balance of the body (Body balance) also plays an important role in the organization of the degree of acidity (pH) in different organs.
5. Maintain the water balance Water balance
Blood plays a crucial role in water balance in the body, maintaining the amount of water present in the body through out the excess water by the kidneys and through the sweat glands in the body.
6. Transfer and the organization of the secretion of hormones, Transport and regulation of hormone
The blood of the organization of the secretion of hormones and glands maintain the rate in parallel in the blood and also the transfer of these hormones from their places of production to places where they operate.
7. The body's defense or protection Defence
Containing the blood on the white blood cells (WBC) that produce antibodies (Antibodies) that defend the body against microbes and viruses attacking (ie, it has a major role in the body's immunity against various diseases).
8. Blood coagulation of blood clotting
Blood work on the prevention of bleeding (Bleeding) by the process of coagulation or blood clotting in the blood clotting factors work (Coagulation factors) that have an important role in the process of stopping bleeding during injury and thus maintain the normal amount of blood in the body.