The male reproductive tract and spermatogenesis
Gadea J., Parrington J., Kashir J., Coward K.
© Cambridge University Press 2013. Objectives: The purpose of the male reproductive system is to (i) produce, maintain and transport sperm and seminal plasma; (ii) discharge sperm within the female reproductive tract; and (iii) produce and secrete androgens for maintaining male reproductive capacity. The objective of this chapter is to briefly review the key components of the male reproductive system and explore their basic structure and functional role. Hormonal regulation and the process of spermatogenesis will also be examined. Structure and function of the male reproductive system. Reproduction is the process by which organisms create offspring. While both the female and male reproductive systems are involved in producing, nourishing and transporting either the egg or sperm, these systems are very different in shape and structure. The male reproductive organs include the testis, epididymis, vas deferens, accessory glands such as the seminal vesicles, prostate and bulbourethral glands, and the copulatory organ, the penis. Testes: The testes are the organs that produce sperm, the mature male gametes (Fig. 3.1). The testes also serve important endocrine functions and represent the source of male sex hormones (androgens), the most abundant of which is testosterone. Each testis descends from a retroperitoneal position through the inguinal canal to reach the scrotum during the eighth month of fetal development. Anatomically, the testes are ovoid glands that are suspended in the scrotum. The blood vessels and nerves to the testis stem from within the abdomen in a multilayered structure called the spermatic cord. Each testis is surrounded by a capsule, the tunica albuginea, which is externally covered by a serosa. From the tunica albuginea, fibrous septa project deep into the testis and converge to form the mediastinum. The septa divide the parenchyma of the testis into multiple testicular lobes, each of which contains convoluted seminiferous tubules. The interstitial tissue between the convoluted tubules is continuous with a layer of loose vascular connective tissue, the tunica vasculosa, which is found beneath the tunica albuginea.