The Male Reproductive Cycle
The development of normal and mature sperm is the key to male fertility. The follicle stimulating hormone (FSH) and luteinizing hormone (LH) regulate the production of sperm. FSH and LH are released from the anterior pituitary, where FSH stimulates the sperm production in the testicles and LH stimulates the production of testosterone.
Testosterone is the male hormone that helps to maintain male sexual characteristics, such as facial hair growth and other masculine qualities. Under the influence of testosterone and other hormones, immature sperm cells develop through several stages and eventually become mature sperm cells called spermatozoa. Sperm complete the maturation process outside the testes.
First, spermatozoa pass into the epididymis, where they gain motility or the ability to move after 18 to 24 hours. Next, mature sperm move through the vas deferens and are stored in the seminal vesicles until ejaculation. Development of immature sperm to mature sperm takes 72 days. Therefore, factors such as fever, medications, cigarette smoking or heavy alcohol use may impact the semen analysis for nearly two and a half months afterward.
The semen analysis is the initial test to determine if there is male infertility. Additional semen tests or consultation with an urologist may be required.
During the process of ejaculation, sperm from the seminal vesicles combine with a thick fluid from the prostate and other glands to create semen. When conceiving naturally, the semen is deposited into a women's vagina, where it travels through the cervix and uterus, and finally into the fallopian tube. Only one to 10 sperm out of every 14 million sperm deposited naturally into the vagina reach the end of the fallopian tube.
LocationsFor more information or a consultation with one of our fertility specialists, please call:
Palo Alto Center
Fertility Physicians of Northern California
Epididymis: A convoluted tubule in each testis that carries sperm to vas deferens.
Follicle Stimulating Hormone (FSH): A hormone produced by the pituitary gland that initiates sperm production.
Luteinizing Hormone (LH): A hormone produced by the pituitary gland that stimulates the Leydig cells in the testes to make and release testosterone.
Seminal Vesicles: Glands at the base of the bladder and connected to the prostate gland that provide nutrients for the semen.
Spermatozoa: The mature male reproductive cells produced by the testes and stored in the epididymis as sperm.
Testes: The male reproductive organs that produce sperm and male hormones.
Testosterone: A male hormone produced by the testes and adrenal glades required for sperm production and development of the male reproductive organs.
Vas Deferens: A duct that carries spermatozoa from the epididymis to the ejaculatory duct.