Ejaculate

Ejaculate, commonly called semen, is the fluid released from the male urethra at ejaculation. In humans, it consists of spermatozoa from the testes and fluid from the accessory glands, including the seminal vesicles and the prostate, which together form a protective medium for sperm.

Physiology and process: Ejaculation involves two linked processes. Emission moves sperm from the testes and epididymis into the ejaculatory ducts. Expulsion then propels the semen through the penis by rhythmic contractions of pelvic floor and other muscles, under autonomic and somatic control.

Composition: Semen is composed mainly of seminal plasma and sperm. The seminal plasma contains energy substrates such as fructose, buffers, enzymes, zinc, and other components produced by the seminal vesicles, prostate, and bulbourethral glands. Spermatozoa are the reproductive cells that contribute to fertilization.

Function: The primary role of ejaculate is to deliver sperm to the female reproductive tract for potential fertilization. The accompanying fluids provide nutrients, buffers, and a suitable environment to support sperm motility and viability during transport.

Clinical and health aspects: Semen analysis is a standard test to assess male fertility, measuring volume, sperm concentration, motility, and morphology. Normal ranges vary, but typical ejaculation volume is about 2-5 milliliters, with sperm concentration around 15-150 million per milliliter. Abnormal results can indicate infertility, infection, or anatomical or neurological issues such as retrograde ejaculation or azoospermia. Factors like age, health, and frequency of ejaculation can influence semen characteristics.