Nipples don’t have muscle inside them — the erection of the nipple happens because of tiny smooth muscle fibers in the areola that contract in response to cold, touch, or sexual arousal.
Different parts of the nail matrix contribute differently to nail thickness
Studies indicate about 79 % of the thickness of the nail plate comes from the nail matrix, while the remaining 21 % is contributed by the nail bed — overturning the notion
Your gut is sometimes called the “second brain”. The gut has 100–500 million neurons, forming the enteric nervous system that controls digestion independently of the brain.
The vagina lacks its own glands.
Unlike many organs, the vagina itself doesn’t have secretory glands—the moisture comes from cervical mucus and surrounding structures
Curly hair may have offered evolutionary advantages
Studies suggest curly hair could have aided heat regulation and brain protection in early humans by trapping air and shielding the scalp from UV radiation more effectively than straight hair.
