The reproductive system is questionably the body system that is the most important influence on life as we know it. It is the w ay in which we procreate and ensure our existence as a species. However, the penis is only one part of the male reproductive system, which constitutes of a series responsible for generating, storing, and transporting the genetic material contained in the sperm cells. The main organs include: testicles (or testes), the epididymides, the vas deferens, the ejaculatory duct, the urethra, and the penis. Others are the scrotum, urogenital opening, and the prostate gland.
The penis is a male organ, responsible for transporting urine and semen outside the body. It is a flexible, that splits into a Y shaped rod (an attached root and a free body, capable of expanding,1 attached to the underside of the pubic bone. The penis consists of various components such as nerve and blood vessels, fibrous tissue and three cylinders of erectile tissue called corpora. Spongy tissue in the penis fills with blood allowing an erection. This is called the Corpus spongiosum, which surrounds the urethra. However, it is the paired dorsal erectile bodies, the corpora cavernosa, which makes up most of the penis and anchors it in place. Below is a graphical representation of basic anatomy of male sexual reproduction:
“During sexual excitement a parasympathetic reflex is triggered and releases nitric oxide (NO)” . The NO relaxes vascular smooth muscles causing arteioles to dilate so that the erectile tissues can fill with blood due to specific brain signals, mean while an expansion of the corpora cavernosa compresses venous drainage. Thus causing an erection. When not sexually aroused, arterioles supplying the erectile tissue are constricted and the penis is flaccid. A loose skin covering called the prepuce or foreskin normally covers the head of the penis, but it has become common to remove the foreskin shortly after birth in a procedure called circumcision.
The reason for an erecting penis is to allow the normally soft penis to harden and thus becoming capable of entering a vagina, where it should ejaculate to approximately a total amount of 50 - 150 million sperm per ml.
“The male sexual response includes erection and orgasm accompanied by ejaculation of semen. Orgasm is followed by a variable time period during which it is not possible to achieve another erection.” Ejaculation, under sympathetic control, is when impulses provoking an erection reach a certain critical level a spinal reflex is initiated. This causes a series of responses such as the reproductive ducts and glands to contract and empty into the urethra. This also triggers a rapid series of contractions in the bulbospongiosus of the penis. These contractions are so powerful that sperm is jettisoned from the penis at a rate of 500 cm/sec.
An orgasm, a very pleasurable sensation, usually follows an ejaculation. Although, some men report that for them ejaculation and orgasms do not always occur simultaneously . Happening simultaneously is generalized muscle contractions and higher blood pressure and heart rate. This is usually followed by immense relaxation and a vasoconstriction of the arterioles of the penis thus making it flaccid.
Semen is the seminal fluid in which the male’s genetic information (contained in sperms) is transported to the female uterus, supposedly fertilizing the egg thus creating a chain reaction that will eventually become a new human being. Semen consists of a complex mixture of fluids and sperm only occupies only 5% of semen and is a grayish white mixture. However, sperm is still one of the most important components in semen. Sperm is produced in the gonads, which are testes. Among other things, semen has clotting factors which enable the fluid to coagulate quickly after ejaculation. It then liquefies via fibinolysin.
Below is a drawn representation of a sperm: