Q: What does male ejaculate consist of?
A: The ejaculate consists of a mixture of four components:
a. Approximately 2 ml (two-thirds) of the ejaculate comes from the seminal vesicles. It contains proteins and enzymes (20-40 mg/ml), as well as highly bioreactive components such as prostaglandins (200 mug/ml), citrate ions (4 mg/ml), spermine (3 mg/ml), and fructose (2 mg/ml).
b. About 0.5 ml of the ejaculate comes from the prostate gland, which contributes high concentrations of citric acid, as well as spermine, a very basic organic molecule of unknown function.
c: About 0.2 ml of the ejaculate is clear fluid that comes from the bulbourethral (Cowper's) gland and acts as lubricant and neutralizing agent in the urethra, where acidic, residual urine would kill the sperm were it not for this fluid.
d. Less than 0.2 ml of the ejaculate are sperm, or spermatozoa, which come from the testes.