Erythrocytes Er (red blood cells rbc)

They were discovered in 17^th century. They vary in their shape:

• discocytes (76 per cent);

• stomatocytes;

• echinocytes;

• spherocytes;

• torocytes;

• dacryocytes;

• planocytes;

• spherocytes;

• ovalocytes;

• acanthocytes and others.

Poikilocytosis - if one can see erythrocytes of different shape in 1 eyesight field simultaneousely. Discoid shape the most widely-spread among RBC allow them transmit capillary better.

Er also differ in their sizes:

• normocytes - cells with diameter 7,5-8,3 mcm and width about 2,1 mcm (their amount is approximately equal to 68 per cent);

• microcytes – if diameter is less (about 15 per cent);

• macrocytes - with larger diameter.

Anizocytosis - if one can see erythrocytes of different size in 1 eyesight field simultaneousely.

Human erythrocytes have no any nucleus. This fact allows them to come through capillary easily. Er is covered by membrane which has antigenic features. This membrane can adsorb and desorb substances coming into blood. Human Er possess large adsorbtive-desorbtive potential. RBC membrane permeability is important for organism availability. Er membrane may be destructed in hypotonic solutions (water, acid et al.) that leads to haemolysis development.

Haemolysis kinds:

1. According to causative agent action:

• mechanic (shaking up, vibration);

• chemical (chlorophorm);

• physical (electrical current);

• osmotic (sodium natrium action);

• biologic (some snakes poisons).

2. According to localization:

• intracellular;

• intravascular (at blood transmissions, toxic animals and insects bites and so on).

Osmotic resistance (ability to resist osmotic forces) is index characterized intravascular haemolysis. Norma: 0,32-0,48% of sodium chloridum.

Er membrane is charged negatively; at this negative charge decreasing RBC can glue together and sedimentate. This reaction received the name velocity sedimentation rate (VSR). Under norma:

• in men – 2,0-10,0 mm/h - widely-spread among doctors (according to new data – 6,0-12,0);

• in women – 2,0-15,0 mm/h (according to new theoretic data - 8,0-15,0) (up to 15,0 - at pregnancy due to hyperfibrinogenemia and at menses as a result of erythrocytes number decreasing because erythrocytes are easily to sedimentate under such conditions);

• in new-borns – 1,0-2,0 mm/h;

• in babies (1 year) – 4,0-10,0 mm/h;

• in the old of both sexes – up to 15,0-20,0 mm/h.

VSR depends on fibrinogen concentration in blood: if its content is more than 3,0 g/l (norma – 2,0-4,0 g/l) VSR is increased. It’s observed in pregnant women and at inflammatory processes. VSR reducing less than 2,0 mm/h – is unfavourable diagnostic sign. But at the same time this index increasing up to 40-100 mm/h (especially to upper limit) may be the sign of tumors particularly malignant.

Erythrocytes amount under norma in men 4,4-5,0 x 10¹²/l; in women – 3,7-4,5 x 10¹²/l. Erythrocytosis means Er amount increasing:

1. Physiological:

• in new-borns;

• at physical work;

• in mountains.

2. Pahological:

• real polycytaemia - Vakez’ disease.

Erythropenia – RBC amount decreasing:

• in pregnant;

• at irradiations et al.

Haemoglobine is an essential structural part in Er. Normal values:

• in men – 135-180 g/l;

• in women – 120-160 g/l;

• in new-borns – up to 200 g/l;

• in pregnant women – up to 110 g/l (physiological hypochromic anaemia).

Main role: oxygen transport (oxyhaemoglobin) and CO₂ (carbohaemoglobine). Adult haemoglobine consists of fractions: “A” – 95-98%, A₂ – 2-3%; fetal haemoglobine (Hb F) – 1-2%.

One can tell about Er saturation by haemoglobine on so-called colour index (CI). It is relative index characterizing Er saturation with Hb. Under norma this index is equal to 0,75-1,0. Er at such CI are called normochromic; if it is more than 1,0 – hyperchromic; less than 0,75 – hypochromic.