Īccording to the histological findings of the British Association of Urological Surgeons based on a research conducted on the autopsy of 22 foreskins, "the prepuce provides a large and important platform for several nerves and nerve endings", The College of Physicians and Surgeons of British Columbia has written that the foreskin is "composed of an outer skin and an inner mucosa that is rich in specialized sensory nerve endings and erogenous tissue." The dartos fascia is only loosely connected with the underlying tissue so it provides the skin mobility and elasticity of the penile skin. The dartos fascia is sensitive to temperature and expands and contracts with temperature changes. The whorl of fibers acts as a sphincter in infants, which opens to allow the passage of urine, but closes to protect the glans penis from foreign matter and contaminants. Elastic fibers are contained in the dartos fascia, which form a whorl at the tip of the foreskin. The human foreskin contains a sheath of muscle tissue just below the skin, formerly known as the peripenic muscle and now called the dartos fascia, most of which is contained in the foreskin. The World Health Organization states that "he frenulum forms the interface between the outer and inner foreskin layers, and when the penis is not erect, it tightens to narrow the foreskin opening. The foreskin is attached to the glans by a frenulum, a highly vascularized tissue of the penis. Like the eyelid, the foreskin is free to move after it separates from the glans, which usually occurs before or during puberty. The mucocutaneous zone occurs where the outer and inner foreskin meet. The outside of the foreskin is a continuation of the skin on the shaft of the penis, but the inner foreskin is a mucous membrane like the inside of the eyelid or the mouth.