Successful reproduction is the ultimate definition of evolutionary fitness. Because fertilization occurs within the reproductive tract of humans, intimate contact between male and female is necessary for spontaneous conception to…
Gametogenesis and steroidogenesis proceed in a continuous fashion in the postpubertal human male. In contrast, the postpubertal human female exhibits repetitive cyclic changes in the hypothalamic–pituitary–ovarian axis that allow: (i)…
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…
Erection, emission and ejaculation An erection is a complex neuropsychologic event. It occurs when blood rapidly flows into the penis and becomes trapped in its spongy chambers. The three systems…
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…
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…
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…
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…
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…
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…
