Papillae

Papillae are small, nipple-like projections found on various tissues, most notably the skin and the tongue. They consist of a core of connective tissue covered by epithelium and can vary in size, shape, and function. In the skin, dermal papillae project upward from the dermis into the epidermis, where they house capillaries and nerve endings. Their interlocking arrangement with the epidermal layer strengthens the dermal–epidermal junction and contributes to fingerprint patterns; they also play a role in wound healing and sensation.

On the tongue, papillae are specialized structures that shape the surface and, in most cases, host taste buds. The main types are filiform, fungiform, circumvallate, and foliate. Filiform papillae are the most numerous, slender projections covering most of the anterior tongue; they are keratinized and provide texture for manipulating food but do not contain taste buds. Fungiform papillae are mushroom-shaped and scattered across the dorsal surface, each typically housing taste buds. Circumvallate papillae are large, dome-shaped structures arranged in a V-shaped row near the back of the tongue; each is surrounded by a trench that contains taste buds. Foliate papillae are folds along the sides of the tongue, containing taste buds, most prominent in children and diminishing with age.

Other mucosal surfaces may feature papillae that serve localized mechanical or sensory roles. In dentistry and developmental biology, the term dental papilla refers to a different structure within a developing tooth that gives rise to dentin and pulp.