Definition: Semen, also called seminal fluid, is the fluid that is expelled from the penis during ejaculation.
Semen contains many ingredients; it's mostly water, but some of the other ingredients -- like sperm -- tend to get all the attention. It is actually produced almost like a just-in-time assembly line, with different parts of the semen coming from different parts of the body and combining just before ejaculation.
Most of the fluid (about 70%) comes from the seminal vesicles, which are glands behind the bladder. The prostate and bulbourethral glands each contribute fluid that makes up most of the rest of semen. The smallest amount (in volume around 1%) is the sperm itself, which is produced in the testes and sent to mix with the other fluids just before ejaculation.
Also Known As: ejaculate, ejaculation, cum
