FORESKIN IN HUMAN
The foreskin is the double-layered fold of smooth muscle tissue, blood vessels, neurons, skin, and mucous membrane part of the penis that covers and protects the glans penis and the urinary meatus. The foreskin is mobile, fairly stretchable, and acts as a natural lubricant. The foreskin is also described as the prepuce, a technically broader term that also includes the clitoral hood in women, to which the foreskin is embryonically homologous.
The foreskin of adults is typically retractable over the glans. Coverage of the glans in a flaccid and erect state varies depending on foreskin length. The foreskin is attached to the glans at birth and is generally not retractable in infancy. Inability to retract the foreskin in childhood should not be considered a problem unless there are other symptoms. The highly innervated mucocutaneous zone of the penis occurs near the tip of the foreskin.
The foreskin may become subject to a number of pathological conditions. Most conditions are rare and are easily treated. In some cases, particularly with chronic conditions, treatment may include circumcision, a procedure where the foreskin is partially or completely removed.
Diagram of a portion of the male anatomy
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. The mucocutaneous zone occurs where the outer and inner foreskin meet. Like the eyelid, the foreskin is free to move after it separates from the glans, which usually occurs before or during puberty. The foreskin is attached to the glans by a frenulum, a highly vascularized tissue of the penis. The World Health Organization states that “the 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 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. Elastic fibers are contained in the dartos fascia, which form a whorl at the tip of the foreskin. 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. The dartos fascia is sensitive to temperature and expands and contracts with temperature changes. The dartos fascia is only loosely connected with the underlying tissue so it provides the skin mobility and elasticity of the penile skin.[medical citation needed]
According 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.”
Langerhans cells are immature dendritic cells that are found in all areas of the penile epithelium,but are most superficial in the inner surface of the foreskin.
The foreskin typically covers the glans when the penis is not erect (top image), but generally retracts upon erection ( image). Coverage of the glans in a flaccid and erect state varies depending on foreskin length.
The World Health Organization (2007) states that there is “debate about the role of the foreskin, with possible functions including keeping the glans moist, protecting the developing penis in utero, or enhancing sexual pleasure due to the presence of nerve receptors”. The foreskin helps to provide sufficient skin during an erection.
The foreskin protects the glans. The foreskin protects the glans of infants from ammonia and feces in diapers, which reduces the incidence of meatal stenosis, and continues to protect the glans from abrasions and trauma throughout life. The fold of the prepuce maintains sub-preputial wetness, which can cause smegma when proper hygiene is not perfomed.
The American Academy of Pediatricians’ 2012 technical report on circumcision found that the foreskin tends to harbor micro-organisms that can lead to urinary tract infections in infants and tend to contribute to the transmission of sexually transmitted infections in adults.