Sejtforma

Sejtforma, or cell form, describes the external geometry of a cell, including its overall shape, size, polarity, and surface characteristics. It reflects how a cell encounters its environment and carries out functions, and it can vary widely among different organisms and tissues. The maintenance and changes of cell shape arise from an interplay of structural components, such as the cytoskeleton, membrane properties, and, when present, the cell wall, as well as turgor pressure, adhesion, and environmental constraints.

In bacteria, shapes are commonly categorized as cocci (spherical), bacilli (rod-shaped), vibrios (comma-shaped), spirilla (spiral), and spirochetes (corkscrew-shaped). In eukaryotic cells, shapes are highly diverse and often linked to function: erythrocytes are biconcave discs; epithelial cells can be squamous, cuboidal, or columnar; neurons possess long axons and dendrites; muscle cells are elongated; plant cells are frequently rigid and rectangular due to cell walls and turgor.

Cell shape is dynamic and can change during growth, division, migration, and differentiation. Cytoskeletal remodeling (actin filaments, microtubules, intermediate filaments), membrane remodeling, and, when applicable, cell wall synthesis drive these changes. Such morphology influences motility, nutrient uptake, signaling, and tissue organization.

Studying cell form involves microscopy and image analysis, including light, fluorescence, confocal, and electron microscopy, to measure parameters such as aspect ratio, curvature, and surface features. Sejtforma is a central concept across microbiology, cell biology, development, and pathology, providing insight into how structure relates to function.