Foreskin

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The nature of the prepuce or foreskin, which is amputated and destroyed by circumcision, must be considered and fully understood in any discussion of male circumcision.[1]

Purpura et al. (2018) describe the foreskin as follows:

"Few parts of the human anatomy can compare to the incredibly multifaceted nature of the human foreskin. At times dismissed as “just skin,” the adult foreskin is, in fact, a highly vascularized and densely innervated bilayer tissue, with a surface area of up to 90 cm, and potentially larger. On average, the foreskin accounts for 51% of the total length of the penile shaft skin and serves a multitude of functions. The tissue is highly dynamic and biomechanically functions like a roller bearing; during intercourse, the foreskin “unfolds” and glides as abrasive friction is reduced and lubricating fluids are retained. The sensitive foreskin is considered to be the primary erogenous zone of the male penis and is divided into four subsections: inner mucosa, ridged band, frenulum, and outer foreskin; each section contributes to a vast spectrum of sensory pleasure through the gliding action of the foreskin, which mechanically stretches and stimulates the densely packed corpuscular receptors. Specialized immunological properties should be noted by the presence of Langerhans cells and other lytic materials, which defend against common microbes, and there is robust evidence supporting HIV protection. The glans and inner mucosa are physically protected against external irritation and contaminants while maintaining a healthy, moist surface. The foreskin is also immensely vascularized and acts as a conduit for essential blood vessels within the penis, such as supplying the glans via the frenular artery."[2]


Contents

Structure

The foreskin (also known as the prepuce) 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.[1] The foreskin comprises more than fifty percent of the epithelium of the penis.[3]

The foreskin is the movable part of the penis. The foreskin is not attached to the underlying structure and is free to glide back and forth.[4] The gliding action reduces the friction of intercourse and helps to prevent abrasions, while conserving vaginal lubrication and moisture.[5]

The epithelium of the outer layer of the foreskin is true skin while the epithelium of the inner layer is mucosal membrane. There is a mucocutaneous boundary at the tip of the foreskin. The mucocutaneous junction is a specific erogenous zone.[6]

The layer of dartos muscle is contained within the foreskin. The dartos muscle keeps the foreskin snugly against the glans. The fibers of the dartos muscle form a whorl at the tip that functions as a sphincter. The sphincter opens to allow urine to flow out, but closes to protect the penis from foreign matter, contaminants, and pathogens.[4][7]

The ridged band area is found at the mucocutaneous junction. The ridged band area is characterized by rete ridges with Meissner’s corpuscles in the ridges.[3]

As with other neurologic structures such as the brain, the tip of the prepuce is richly supplied with blood by important vascular structures.[3] The prepuce serves as a conduit for several important veins.[8] The glans penis receives blood through the frenular artery.[9]

Physiological functions

Protective functions

The foreskin provides physical protection to the glans penis and inner mucosa, protecting the mucosal tissue from pathogens, pollutants, friction, injury, and drying out.. The foreskin protects the glans penis and meatus from abrasion and irritation from ammoniacal diapers.[10] [11]

In the absence of the foreskin about ten to twenty percent of boys suffer urethral stricture (meatal stenosis) requiring further treatment.[12] Frisch & Simonsen (2016) reported the incidence of meatal stenosis to be 3.7 times higher in circumcised boys.[12]

Immunological functions

Fleiss et al. (1998) have listed numerous immunological functions of the foreskin that help to protect the human body against infection. The sub-preputial moisture contains cathepsin B, chymotrypsin, neutrophil elastase, cytokines, and lysozyme, which has the capacity to desttroy the cell walls of bacteria. The preputial muscles keep the tip of the foreskin closed to keep out pathogens.[8]

Sexual functions

The foreskin is a sexual organ. It provides both mechanical and erogenous functions in sexual intercourse.[8]

The gliding action facilitates intromission.[5][13] [14] During the thrusting of sexual congress, the gliding action reduces abrasions and irritation in the female partner and avoids problems with vaginal dryness.[5][13]

Sensory functions

Nature designed the foreskin to be an erogenous sensory organ. The foreskin has a layer of muscle called the dartos muscle sheath that provides the foreskin with elasticity, flexibility, and stretchiness. There is a mucocutaneous region at the tip of the foreskin where outer skin changes to inner mucosa. Winklemann (1959) identified the foreskin as a specific erogenous zone (meaning an area of acute erogenous sensation). Winklemann reported rete ridges in the foreskin with nerves set close to the surface with closely set networks.[6]

Lakshamanan & Prakash (1980) report the "prepuce covers the glans completely and snugly like a hosiered material and continues to do so through the entire span of life of the male", which they explain as being caused by the smooth muscle fibers within the prepuce. The prepuce is free to glide back and forth. When it does, it must stretch to go over the glans penis.[4]

Taylor et al. (1996) carried out a histological study of the foreskin. (Histology is the microscopic examination of cells and tissues.) Taylor et al. found an area of rete ridges just inside the tip of the foreskin that he called the ridged band. The ridges were found to have nerve endings at the top of the ridges. They report that the ridged band area moves to the shaft of the penis when the penis becomes erect where the nerves are subject to stimulation.

The following content is part of the Circumpendium.

Anatomy and function of the foreskin in detail

The foreskin covers the glans, thus protecting it from pollutants, friction, injury and drying out. It consists of two superimposed layers, which are only joined together at the very end. The ridged band is located just inside the tip of the foreskin.

While the outer foreskin layer is an extension of the penile shaft skin, the inner foreskin layer, which lies flat against the glans,[15] is a mucous membrane. The inner layer is an extraordinarily complex tissue. It contains apocrine glands which produce Cathepsin B, lysozymes, chymotrypsin, neutrophil elastase, cytokines and pheromones such as androsterone.[8] Indian scientists have shown that the subpreputial moisture contains lytic material which has an antibacterial and antiviral effect.[4] The natural oils lubricate, moisten and protect the mucous membranes of both the glans and the inner foreskin layer.[15] The tip of the foreskin is supplied with ample amounts of blood through important blood vessels.[16]

The foreskin serves as a pathway for many significant veins. In addition the foreskin is saturated with very many nerve endings and tactile corpuscles, the same receptors that exist in the fingertips. The enormous density of nerves and mechanoreceptors make the foreskin the most sensitive part of the body, approximately 10 times more sensitive than the fingertips. This also distinguishes the human penis from those of other mammals, which in contrast have the main concentration of nerves in the glans, and not in the foreskin.

The two foreskin layers provide a skin reserve, into which the growing shaft expands during an erection. Depending to the individual length of a man's foreskin, it thereby retracts more or less far. In some men, the foreskin still fully covers the glans during an erection, in others the glans is partly or completely exposed.

In addition, the foreskin, in combination with the shaft skin, allows a natural gliding action. During intercourse as well as masturbation the outer skin is in contact with the vagina or the hand respectively. The penile shaft moves mostly within its skin and the skin only moves at the end of its thrust. Due to this, the friction with the vagina or hand is reduced. The sexual stimulation mostly occurs through the stretching and movement of the foreskin, when it is pulled over the glans and back, as well as the direct stimulation of the inner foreskin when it is exposed and comes into direct contact with the vagina or the hand. The frenulum may limit retraction.

The foreskin in childhood is fused with the glans penis by a synechia.

See also

External links

  •   (1 July 2016). The prepuce, DOC, Doctors Opposing Circumcision. Retrieved 28 September 2019.

References

  1. ↑ a b   Cold, C.J., Taylor, J.R.. The prepuce. BJU Int. 1 January 1999; 83 Suppl 1: 34-44. PMID. DOI. Retrieved 10 October 2019.
  2. ↑   Purpura, V., Bondioli, E., Cunningham, E.J., et al. The development of a decellularized extracellular matrix–based biomaterial scaffold derived from human foreskin for the purpose of foreskin reconstruction in circumcised males. Journal of Tissue Engineering. 2018; 9: 1-11. PMID. PMC. DOI. Retrieved 25 September 2019.
  3. ↑ a b c   Taylor, J.R., Lockwood, A.P., Taylor, A.J.. The prepuce: specialized mucosa of the penis and its loss to circumcision. Brit J Urol. 1996; 77: 291-5. PMID. DOI. Retrieved 14 October 2019.
  4. ↑ a b c d   Lakshmanan, S, Prakash, S.. Human prepuce: some aspects of structure and function. Indian J Surg. 1980; 44: 134-7.
  5. ↑ a b c   Warren, John, Bigelow, Jim. The case against circumcision. Brit J Sex Med. error; Retrieved Error: Invalid time..
  6. ↑ a b   Winkelmann, R.K.. The erogenous zones: their nerve supply and significance. Mayo Clin Proc. 21 January 1959; 34(3): 39-47. PMID. Retrieved 14 October 2019.
  7. ↑   Jefferson. The peripenic muscle; some observations on the anatomy of phimosis. Surgery, Gynecology, and Obstetrics (Chicago). 1916; 23(2): 177-81. Retrieved 14 October 2019.
  8. ↑ a b c d   Fleiss, P., Hodges, F., Van Howe, R.S.. Immunological functions of the human prepuce. Sex Trans Infect. October 1998; 74(5): 364-67. PMID. Retrieved 15 October 2019.
  9. ↑   Persad, R., Sharma, S., McTavish, J., et al. Clinical presentation and pathophysiology of meatal stenosis following circumcision. Brit J Urol. 1995; 75(1): 91-3. PMID. DOI. Retrieved 15 October 2019.
  10. ↑   Gairdner, D.. The fate of the foreskin: a study of circumcision.. Brit Med J. 24 December 1949; 2: 1433-7. PMID. PMC. DOI. Retrieved 14 October 2019.
  11. ↑   Dobanavacki, D., Lucić Prostran, B., Sarac, D., et al. Prepuce in boys and adolescents: what when, and how?. Med Pregl. 2012; 65(7-8): 295-300. DOI. Retrieved 14 October 2019.
  12. ↑ a b   Frisch, Morten, Simonsen, J.. Cultural background, non-therapeutic circumcision and the risk of meatal stenosis and other urethral stricture dis-ease: Two nationwide register-based cohort studies in Denmark 1977-2013. The Surgeon. 1 April 2016; 16(2): 107-18. DOI.
  13. ↑ a b   Morgan, W.K.C.. The rape of the phallus. JAMA. 1965; 193: 123-4. PMID. DOI. Retrieved 15 October 2019.
  14. ↑   Taves, D.. The intromission function of the foreskin. Med Hypotheses. 2002; 59(2): 180. PMID. DOI. Retrieved 15 October 2019.
  15. ↑ a b   Prakash, S., Raghuram, R., Venkatesan, et al. Sub-preputial wetness - Its nature. Ann Nat Med Sci (India). 1982; 18(3): 109-12. Retrieved 14 October 2019.
  16. ↑ Dr. med. Wolfram Hartmann, Stellungnahme zur Anhörung am 26. November 2012 im Rechtsausschuss des Bundestages
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