The 100,000th scientific article on the subject of spermatozoa was recently published. Many studies have evaluated the characteristics of this important cell leading to great discoveries. Since its first observation and description in 1677, many important characteristics have been described regarding this highly fascinating gamete. In this review, our objective has been to provide a historical ...

Basic understanding of the male reproductive system is fundamental in effective evaluation and treatment of male infertility. This chapter is a concise introduction to the male reproductive anatomy and the intricately designed process of spermatogenesis along with its hormonal control.

The male reproductive hormonal axis Maintenance of normal reproductive function is depend­ ent on the coordinated release of hormones in the hyp o­ thalamic−pituitary−testis cascade. Gonadotropin­releasing hormone (GnRH) is released in a pulsatile pattern into the pitu­ itary portal blood system from neuroendocrine cells in the basal hypothalamus and acts to stimulate gonadotropes in the anter­...

The boar has a tremendous impact on the reproductive efficiency of the swine breeding herd. Depending on the collection frequency and insemination dose, semen from a single boar can be used to breed between 750 and 1000 sows per year. As a result, reproductive failure of a single male influences a large number of sows. Consequently, a thorough understanding of the basic aspects of male reproduc...

Selection clearly focuses on differences in reproduction, but studies of reproductive physiology generally have been carried out in a near vacuum of modern evolutionary theory. This lack of contact between the two fields may be about to change. New ideas indicate that sexual selection by cryptic female choice has affected the evolution of products in male semen that influence female reproductiv...

Social behavior can influence physiological systems dramatically yet the sensory cues responsible are not well understood. Behavior of male African cichlid fish, Astatotilapia burtoni, in their natural habitat suggests that visual cues from conspecifics contribute significantly to regulation of social behavior. Using a novel paradigm, we asked whether visual cues alone from a larger conspecific...

Cholesterol, being the starting point of steroid hormone synthesis, is a long known modulator of both female and male reproductive physiology especially at the level of the gonads and the impact cholesterol has on gametogenesis. Less is known about the effects cholesterol homeostasis may have on postgonadic reproductive functions. Lately, several data have been reported showing how imbalanced c...