folikulu

Folikulu is a term found in biology and medicine that refers to a small sac, pouch, or cavity associated with a structure or cell. The word is derived from the Latin foliculus, meaning a small bag, and in some languages it functions as a transliteration or variant of the English term follicle. In English usage, follicle is the standard form, while folikulu may appear in linguistic variants or in regional scientific glossaries.

In anatomy and physiology, folikulu commonly denotes several well-known structures. Hair follicles are tubular invaginations of the skin that enclose hair roots, cooperate with sebaceous glands, and participate in the hair growth cycle, which includes phases such as anagen, catagen, and telogen. Ovarian follicles are compartments within the ovaries that contain developing oocytes and supporting cells; they progress from primordial to primary, secondary, and antral stages and are central to the hormonal regulation of reproduction and ovulation. Lymphoid follicles are aggregates of lymphocytes within lymph nodes and the spleen, forming germinal centers during immune responses and contributing to humoral immunity.

While hair, ovarian, and lymphoid follicles reflect the main uses of the term, the concept of a follicle also appears in other biological contexts, including plant and bird anatomy, where small cavity-like structures exist around seeds, glands, or hair-like elements. The precise structure and function of a folikulu depend on the tissue type but share the common feature of housing or surrounding a specialized element and participating in growth, protection, or secretion.