Blood physical-chemical peculiarities and constants.

1. Blood colour - depends on haemoglobine. Arterial blood is brightly red because of oxyhaemoglobine (haemoglobine connected with oxygen) big amount. Venous blood is dark red with blue shade. Such blood colour is linked with presence not only of oxydated haemoglobine but also reducted haemoglobine.

2. Blood viscosity or internal friction. It is often determined comparatively to water viscosity: if the latest one is equal to 1, blood viscosity is equal to 4,0-5,0. In new-borned - 10,0-14,0; in 1 month – like in the adult. In girls this index is less than in boys. Main reasons for viscosity increasing:

• in mountains;

• hypercapnia (carbonic acid content increasing in blood);

• inflammations;

• hypertony;

• atherosclerosis;

• at feeding of mainly animal food (proteins-rich) – meat, eggs.

Main reasons for viscosity decreasing:

• at vegeteranian feeding.

Viscosity depends on formed elements (mainly erythrocytes) amount and proteins concentration.

3. Blood density – 1,056-1,060. It is increased at blood condensation; it is decreased – at its liquerfaction. Density level depends on formed elements (mainly erythrocytes) amount and proteins concentration.

4. Osmotic pressure – force that makes water transmit from less concentrated solution in more concentrated. Sodium chloridum is essential for its support (60 per cent of this pressure depends on it). It is the same in all internal environment elements (blood, lymph, tissular liquid). It remains constant even at big water and salts passing into the blood because of their removal by kidneys. Osmotic pressure is supported by means of receptors located in vascular vessels wall and in hypothalamus. Normal value: 7,3-7,6 atmospheres. Solutions with equal osmotic pressure are called isotonic (for example, 0,85% solution of sodium chloridum, 5,5 % solution of glucose). If osmotic pressure in solution is more - it is called hypertonic and, correspondingly, if less - hypotonic.

5. Oncotic pressure - is created by blood proteins (mainly low-weighted albumines). Its level is fluctuated from 25 till 30 mm merc col under physical conditions. It is essential for:

• transcapillary exchange;

• uropoiesis;

• absorbtion;

• lymph formation (lymphopoiesis).

6. Acid-alkaline equillibrium – correlation between acid and alkaline equivalent in blood. This is reaction caused by H⁺-ions concentration. PH or hydrogenium index is used for its evaluation. If pH is equal to 7,0 the environment is called neutral; less than 7,0 – acid; more than 7,0 – alkaline. Norma: in venous blood – 7,34, arterial blood – 7,4; blood in a whole – 7,35-7,47. At birth acidosis is physiologic. Ph is supported by: buffer systems, excretory organs and lungs.

Buffer systems:

• bicarbonate,

• phosphate,

• protein,

• haemoglobine (75 per cent of all system).

At muscular tension increasing acid products come into blood (lactic acid, carbonic acid) and movement to acid side (acidosis) is observed. At increased carbonic acid releasing (with lungs at hyperventillation) movement to alkaline side (alkalosis) occurs.

Blood protheins are 7-8 % or 65-85 g/l. Their population is not homogenic.

Albumins – (60 % or 35-50 g/l) produced in liver; are agile, low-weighted, they are important for:

• oncotic pressure support;

• bilirubin transport;

• hard metals salts transport;

• fat acids transport;

• medicines transport (proteins increase action periods for them).

Globulins (40% or 30-35 g/l) are formed in liver, bone marrow, spleen. Role:

• form antibodies;

• antitoxines;

• agglutinines;

• blood coagulation (some of them are clotting factors);

• phospholipid transport;

• cholesterol transport;

• steroid hormones transport;

• oncotic pressure support (less than albumins);

• blood density support;

• buffers;

• blood viscosity determination;

• nutritive function.