Penis

Parts of the penis
Root of the penis (radix): It is the attached part, consisting of the bulb of penis in the middle and the crus of penis, one on either side of the bulb. It lies within the superficial perineal pouch. Body of the penis (corpus): It has two surfaces: dorsal (posterosuperior in the erect penis), and ventral or urethral (facing downwards and backwards in the flaccid penis). The ventral surface is marked by a median raphe.

Structure of the Penis
The human penis is made up of three columns of tissue: two corpora cavernosa lie next to each other on the dorsal side and one corpus spongiosum lies between them on the ventral side. The enlarged and bulbous-shaped end of the corpus spongiosum forms the glans penis, which supports the foreskin or prepuce, a loose fold of skin that in adults can retract to expose the glans. The area on the underside of the penis, where the foreskin is attached, is called the frenum (or frenulum).

The male urethra, which is the last part of the urinary tract, traverses the corpus spongiosum, and its opening, known as the meatus (pronounced /miːˈeɪtəs/), lies on the tip of the glans penis. It is a passage both for urine and for the ejaculation of semen. Sperm are produced in the testes and stored in the attached epididymis. During ejaculation, sperm are propelled up the vas deferens, two ducts that pass over and behind the bladder. Fluids are added by the seminal vesicles and the vas deferens turns into the ejaculatory ducts, which join the urethra inside the prostate gland. The prostate as well as the bulbourethral glands add further secretions, and the semen is expelled through the penis. The raphe is the visible ridge between the lateral halves of the penis, found on the ventral or underside of the penis, running from the meatus (opening of the urethra) across the scrotum to the perineum (area between scrotum and anus). The human penis differs from those of most other mammals, as it has no baculum, or erectile bone, and instead relies entirely on engorgement with blood to reach its erect state. It cannot be withdrawn into the groin, and it is larger than average in the animal kingdom in proportion to body mass.

peyronie's diease
http://www.imminst.org/forum/index.php?showtopic=30762&st=0

Erectile Dysfunction and treatments
Treatment of erectile dysfunction with pycnogenol and L-arginine.

http://www.ncbi.nlm.nih.gov/pubmed/12851125

Tissue engineering of the penis
http://www.altpenis.com/penis_news/tissue_engineering.shtml

Penis Exercises
http://www.penisadd.com/

Aged related changes in the penis
http://www.healthinaging.org/agingintheknow/chapters_ch_trial.asp?ch=51

http://webcache.googleusercontent.com/search?q=cache:1VCVMfZKKwYJ:www.queendom.com/articles/articles.htm%3Fa%3D23+aging+of+the+penis+Dr.+Robert+Birch&cd=2&hl=en&ct=clnk&gl=au

http://men.webmd.com/features/life-cycle-of-a-penis

Article sources
http://en.wikipedia.org/wiki/Human_penis

http://anatowiki.wetpaint.com/page/Male+reproductive+system