Semen is the cloudy white body fluid that is emitted from the urethra of the penis during ejaculation. Most of the fluid in semen is made up of secretions from male reproductive organs.
65 per cent of the fluid is produced by the seminal vesicles
30 to 35 per cent by the prostate
5 per cent from the testicles and epididymes
Semen contains citric acid, free amino acids, fructose, enzymes, phosphorylcholine, prostaglandin, potassium, and zinc. The average volume of semen produced in a single ejaculation varies from 2 to 5 ml. The semen from a single ejaculation may contain between 40 million and 600 million sperm, depending on the volume of the ejaculate and the length of time since the last ejaculation. Samples used for medical purposes are obtained by having the donor masturbate. If a sample cannot be produced without sexual intercourse, non-reactive condoms can be used to collect the semen.
I just Googled, copy, and pasted. I always thought that was my knee cartilage I was shooting out and that's why my knees hurt.