In everyday biology, humans do not have “tendrils” as an actual anatomical structure. The word is usually being used metaphorically when applied to people.
Literal meaning
In strict scientific and dictionary use, a tendril is a thin, threadlike organ found in many climbing plants (like peas, grapes, or cucumbers) that coils around supports to help the plant climb and stay upright. Humans do not grow or possess these plant structures, so there are no true tendrils in the human body.
Metaphorical use in humans
When people talk about “tendrils” in humans, they almost always mean something that looks or behaves like a plant tendril. For example, someone might describe curls of hair, branching nerves or blood vessels on a scan, or spreading scar tissue as “tendrils” because they are thin, branching, and seem to extend or wrap around other structures. In psychology or poetry, “mental tendrils” or “emotional tendrils” may describe thoughts or feelings that spread out and connect to many things, again by analogy to plant tendrils.
Related biological structures
There are delicate, thin, branching structures in the human body that can visually resemble tendrils, such as fine nerve fibers, capillary networks, or cellular projections like cilia and microvilli, but they are not called tendrils in formal anatomy. When medical imaging reports informally mention “tendrils” of tissue (for example, tumor extensions), that wording is descriptive, not the name of a real human organ or standard structure.