An appropriate microenvironment in each segment of the male reproductive
tract is crucial for the successful maturation and motility of sperm and thereby for male
fertility. Spermatozoa are produced in the testes and transported to the epididymis
along with the seminiferous tubular fluid. The epididymis contains an epididymal
milieu that maintains the optimal conditions necessary for sperm maturation and
storage. The composition of the luminal fluid is gradually changed along the
epididymal duct due to absorption and secretion processes. The main changes in
epididymal fluid and other fluids produced by accessory glands will be reflected in the
ionic content, osmolality, pH and spermatocrit. Sperm motility is a good predictor of
human male fertility that is controlled by some parameters such as bicarbonate and
calcium concentrations, which constantly fluctuate throughout the reproductive ducts.
The spermatozoa leaving the epididymis along with the epididymal fluid will join the
secretions from the prostate and seminal vesicles, thus forming the seminal plasma.
More attention should be paid to male reproductive tract fluids, namely its ionic
composition and pH in order to unravel the causes of idiopathic infertility, which
represents an elevated percentage of infertile men.
Keywords: Bicarbonate, Calcium, Epididymal fluid, Epididymis, Ions, Ionic
transporters, pH, Seminal plasma, Seminal vesicles, Seminiferous tubular fluid,
Sperm capacitation and motility, Spermatozoa, Prostate.
