la red blood cells.

• Relative reduction in the number of red blood cells can be observed when diluted
  blood in people with kidney disease (elimination is complicated fluid from the body),
  the introduction of large amounts of blood substitutes.
  
• absolute decline in the number of red blood cells - is the main criterion
  anemia.

Anemia can be divided into the following types:

1. Deficit - anemia in which the lack of any any "spare"
   to build red blood cells (belkovodefitsitnye, vitaminodefitsitnye,
   iron-). "Parts" may be an insufficient quantity of dietary
   or incompletely absorbed from the intestine. Can be observed and their relative
   deficiency during pregnancy and adolescence, when the need for
   "building materials" exceed their intake into the body.
   
2. posthemorrhagic (due to acute and chronic blood loss)
   anemia. In fact, chronic hemorrhagic anemia is also scarce: when
   hemorrhage lost proteins, vitamins and iron.
   
3. hypo-and aplastic (congenital and acquired), anemia raises
   for loss or disasption of the functioning of stem cells (progenitor
   red blood cells) in bone marrow. Acquired deficiency anemia can develop after exposure to radiation
   , congenital - the result of mutations.
   
4. hemolytic (inherited and acquired) anemia. Acquired
   anemia occur when the effects of various chemicals [their role can
   some dasgs, antibodies, microbial toxins (for malaria)] or mechanical
   factors (eg, red blood cells can ranitsya of artificial heart valve).
   Hereditary anemia - the result of mutations, red blood cells of people with hereditary hemolytic anemia
   have a defect in the membranes (shells) or abnormal hemoglobin
   .

Increasing the number of red blood cells (polycythemia):

1. Absolute erythrocytosis may be due to amplification of normal hematopoiesis
   . It can occur in chronic lung disease, heart defects
   , congenital hemoglobinopathies. In people with abnormal hemoglobin
   compensatory increase of red blood cells in 1 ml of blood, because
   hemoglobin can not carry oxygen in sufficient quantity. Not
   quality, so many. In chronic renal ischemia can also occur
   erythrocytosis, as they produced in larger quantities than normal,
   erythropoietin, which stimulates hematopoiesis.
   
2. Absolute erythrocytosis may be caused by abnormal blood -
   neoplastic diseases of the hematopoietic system - disease Vakeza .
   
3. Relative erythrocytosis occurs when dehydration.

morphology of red blood cells:

change shape, size, color of red blood cells
underlies the classification of anemias.

1. Reducing the diameter of red blood cells, microcytosis , is observed at
   iron deficiency and hemolytic anemia.
   
2. increase the diameter of red blood cells, macrocytosis , is observed at
   In ₁₂ - and folievodefitsitnyh anemia (vitaminodefitsitnye anemia). When
   hypoplastic anemia may also be observed macrocytosis.
   
3. change in the shape of red blood cells ( poikilocytosis - red blood cells have different
   form) can be observed in iron-deficiency anemia, some
   hemoglobinopathies (sickle cell anemia, thalassemia) .

most
best shape for red blood cell - a form of biconcave disk. In this form
erythrocyte best to carry oxygen. The best size - 7 microns. If he
will be less worse is to carry oxygen, and ifmore- the red blood cells will
less to live. A substantial part of their lives, they will in the bone marrow, except
addition, such large cells are destroyed faster in
spleen.
References:

• The pathophysiology of organs and systems: Textbook / VA. Voinov, N. Losev,
  AB Saltykov, AV Oatmeal; NovSU them. Yaroslav the Wise. - Novgorod, 1998. - 154
  with.
  
• Danilova LA Blood and urine tests. - 2 ed., Revised and supplemented. - St., Inc.
  "Salita - LLC Dean Publishing, 1999. - 128 pp.