Anatomy and physiology of the male reproductive system and potential targets of toxicants

Toxicology of Reproductive and Endocrine System; This introductory chapter offers a basic overview of male reproduction, specifically the anatomy and physiology of the male reproductive system. Comprehension of normal anatomy and physiology is necessary to (1) fully understand the severity of toxicant-induced damage to structures and/or functions of the male reproductive system, (2) design more powerful experiments that analyze potential male reproductive toxicants, and (3) identify numerous potential targets of toxicants in the male reproductive system. This chapter begins with an overview of the hypothalamic-pituitary-testicular axis and its interaction with additional components of the male reproductive system. This is then followed by detailed presentation of the composition of the testis and the interrelationships of the testicular cells, spermatogenesis, the excurrent ducts that carry spermatozoa out of the testis, the accessory sex glands that supply the seminal plasma of semen, the cellular communication within the testis, the reproductive tract's development, and normal male sexual behavior. The chapter's conclusion emphasizes the foundational importance of the male reproductive system to desgining, conducting, and interpreting reproductive toxicology research.