anucleaatilised

Anucleaatilised refers to cells or cell fragments that lack a cell nucleus. This feature is a result of differentiation or fragmentation during maturation and is associated with specialized functions that benefit from more cytoplasmic space, reduced need for transcription, or rapid cellular responses.

The best-known examples are mature mammalian red blood cells (erythrocytes) and platelets. In mammals, erythrocytes lose their nucleus during erythropoiesis in the bone marrow, a process called enucleation. The mature erythrocyte lacks a nucleus and mitochondria, contains mostly cytoplasm filled with hemoglobin, and relies on glycolysis for energy. This design maximizes oxygen-carrying capacity and permits easy passage through narrow capillaries, but it also means mature red blood cells cannot repair DNA or synthesize new proteins. Platelets are anucleate cytoplasmic fragments derived from megakaryocytes and play a central role in hemostasis; they contain granules and mitochondria but no nucleus.

Anucleation is not universal among all vertebrates. Many non-mammalian vertebrates retain nucleated red blood cells, and some plant cells also become anucleate during maturation. For example, certain plant phloem sieve elements lose their nucleus as part of their specialization for long-distance transport, with companion cells maintaining the living functions.

Overall, anucleaatilised structures illustrate how the removal or absence of a nucleus can enable specific physiological roles, particularly in transport and rapid-response processes, while constraining the cell’s capacity for growth and protein synthesis.