Spherocyte

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Normal red blood cells (a and b), c spherocytes, and d thorn apple cells

Spherocytes are spherically changed erythrocytes . Since they are usually smaller than erythrocytes, they are also called microspherocytes . Their surface-to-volume ratio is lower and the hemoglobin is more densely packed. In contrast to the erythrocytes, they have no central lightening. Spherocytes have a reduced life span because they are difficult to deform.

Spherocytes are congenital in spherical cell anemia (membrane defect) and acquired in autoimmune hemolytic anemia (damage to the cell membrane by autoantibodies). In dogs, too, spherocytosis is a diagnostic indication of autoimmune hemolytic anemia; in cats, on the other hand, normal erythrocytes lack the central light, so that spherocytes cannot be distinguished from small erythrocytes.

Spherocytes are pathologically altered erythrocytes. The osmotic pressure in the erythrocytes is equal to the osmotic pressure in the blood plasma . However, the oncotic (colloid osmotic) pressure in the erythrocytes is considerably higher. In order to equalize this pressure, or to prevent it from occurring in the first place, pumps are constantly active in the erythrocyte membrane, which channel electrolytes into the blood plasma. When these pumps are deactivated, e.g. B. through metabolic toxins, the oncotic pressure in the erythrocytes increases. Now, following the oncotic pressure gradient, water strives into the erythrocyte. An outward flow of water with reversed pressure conditions would lead to the so-called " thorn apple shape ".

Due to the premature breakdown of the spherocytes, the systems of the liver and spleen are often overloaded, resulting in the clinical pictures of enlarged spleen and non-infectious jaundice .

swell

  • RF Schmidt, F. Lang, G. Thews: Physiology of humans. Springer, Berlin et al. 2000, ISBN 3-540-66733-4 .
  • M. Tas: The ultimate script in functional pathology. Facultas Verlag, Vienna 2008.

Individual evidence

  1. ↑ Douglas Weiss and Harold Tveldten: Spärozytose. In: Michael D. Willard and Harold Tveldten (eds.): Laboratory diagnostics in small animal practice . Elsevier, Urban & Fischer, 2011, ISBN 978-3-437-31387-5 , p. 56.