Phenotypic sex differentiation
Internal genitalia Unlike the bipotential gonads and external genitalia, the male and female internal genitalia arise from separate duct systems (Fig. 6.1). Development of these structures occurs in parallel and…
Puberty in girls
Puberty is the process by which the immature individual will acquire the physical and behavioral attributes that allow him or her to reproduce. In girls, puberty is largely the response…
Puberty in boys
Puberty is the process by which the immature individual will acquire the physical and behavioral attributes that allow him or her to reproduce. In males, puberty is largely the response…
Microscopic anatomy of the male reproductive tract
Testes The testes have two distinct functions: spermatogenesis and androgen production. Spermatogenesis occurs within distinct structures called seminiferous tubules (Fig. 8.1). These tubules lie coiled within lobules whose ducts all…
Gonadal development in the embryo
Role of sex chromatin in reproductive development All mammalian females are homogametic and represent the “default” pathway in sexual differentiation. Homogametic describes the sex whose cell nuclei contain two similar…
Steroid hormone biosynthesis
Cholesterol and the steroid production pathway Cholesterol is the building block of steroid hormones. All steroid-producing organs with the exception of the placenta can synthesize cholesterol from acetate. Under most…
Steroid hormone mechanism of action and metabolism
Mechanisms of steroid action Steroid hormones exert their effects via a unifying basic mechanism: the induction of new protein synthesis in their target cells. These induced proteins may be hormones…
1: Normal human reproduction
Pituitary structure and function There are three lobes to the pituitary gland (hypophysis): the anterior lobe, the posterior lobe and the pars intermedia, a small intermediate structure lying between the…
