Ejaculation

Ejaculation is the expulsion of semen through the urethra, usually in rhythmic contractions and often during orgasm. It involves coordinated activity of the reproductive tract, pelvic muscles, and nervous system.

Emission: Emission is the movement of sperm and glandular fluids into the posterior urethra before expulsion. This first phase gathers semen in the urethra before the forceful expulsive phase.
Semen: Semen is the fluid ejaculated through the penis, containing sperm and secretions from reproductive glands. It is the material transported and expelled during ejaculation.
Retrograde ejaculation: Retrograde ejaculation occurs when semen enters the bladder instead of exiting through the penis. It reverses the usual outward route of semen during ejaculation.
Semen analysis: Semen analysis is laboratory testing of an ejaculate to assess sperm and semen characteristics. An ejaculate provides the sample used to evaluate male fertility.
Expulsion reflex: The expulsion reflex is the coordinated sequence of pelvic muscle contractions that drives semen through the urethra. It produces the rhythmic contractions that expel semen from the body.
Spermatozoon: A spermatozoon is a mature male reproductive cell capable of fertilizing an egg. Sperm cells are one component of semen, though semen can contain none.
Anejaculation: Anejaculation is the inability to expel semen, despite sexual stimulation or orgasm in some cases. It is the absence of the expulsion process.
Male infertility: Male infertility is reduced ability to cause pregnancy because of reproductive or sexual factors. Disruptions in semen production, transport, or expulsion can affect fertility.
Sympathetic nervous system: The sympathetic nervous system is the autonomic division that mobilizes organs and regulates involuntary functions. Sympathetic signaling helps move reproductive fluids into the urethra during emission.
Prostate: The prostate is a gland below the bladder that contributes fluid to semen and surrounds the upper urethra. Prostatic secretions join the fluids expelled during ejaculation.

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