Testicles
Sperm cell
Penis
Hormonal regulation
The male gonad, the testicle is located outside the abdominal cavity, in the scrotum. After sexual maturation sperm is continuously produced here. Certain cells of the testicle produce the hormone called testosterone. The sperm travels from the testicles to the epididymis, where further maturation takes place. The spermiums travel from the epididymisinto the muscular vas deferens during sexual arousal. Two glands are connected to the vas deferens, the seminal vesicle and the prostate. The seminal vesicle's excretion contains sugar, which feeds the sperm. The prostate produces a mildly acidic excretion but the semen is mildly alkaline which is essential to the survival of the sperm. The excretions of these two glands mixed with sperm is called semen. During ejaculation the semen leaves the vas deferens and is propelled from the body through the urethra which runs along the axis of the penis.
Sperm cells are created in the testicle's convoluted spermatic cord, through meiosis, a cell division that halves the number of chromosomes The immature sperm cell is globular and it takes several weeks for it to become mobile. The maturation process ends in the epididymis. Testosterone is produced by the endocrine cells situated in the connective tissue among the seminiferous tubules. The testicles require a lower temperature to produce the sperm cells than the average body temperature, this is why they are located outside the abdominal cavity, in the scrotum.
The mature sperm cell is a small cell, capable of independent movement. It is a very characteristic cell, it has two main parts, the head and the tail. The nucleus is located in the head area, carrying the DNA. The tail or "flagellum" helps propel the sperm forward.
The penis is the male reproductive organ. It has two columns of tissue running along its sides, these are called corpus cavernosum (cavernous body). These fill up with blood during sexual arousal. The corpora cavernosa (cavernous bodies) filling up with blood results in the erection of the penis. The head of the penis is called glans, this is an area located on the top/apex of the penis, it has many vessels and nerve endings. The stimulation of it leads to the ejaculation of semen.
In males the sexual hormones and the sperm cells are produced continuously from puberty onwards. One of the stimulating hormones of the pituitary gland and testosterone increases the production of sperm in the testicles. Another stimulating hormone helps the production of testosterone. Their blood levels do not show the cyclicity observed in females, but it changes with aging.
