- Describe oogenesis, its relationship to follicular maturation, and the roles of pituitary and ovarian factors in their regulation.
- Describe gonadotropin control of ovarian function.
- List the target organs and principal physiologic actions of estrogen and progesterone and how they interact with each other.
- Describe the cellular mechanisms of action for estrogen and progesterone.
- Describe the endometrial (proliferative and secretory phases) and ovarian events that occur throughout the menstrual cycle and correlate them with the changes in blood levels of pituitary and ovarian hormones.
- Identify the pathways of sperm and egg transport required for fertilization and for movement of the embryo to the uterus.
- Describe the principal endocrine functions of the placenta, particularly in rescue of the corpus luteum and maintenance of pregnancy, and the fetal adrenal-placental interactions involved in estrogen production.
- Understand the roles of oxytocin, relaxin, and prostaglandins in the initiation and maintenance of parturition.
- Explain the hormonal regulation of mammary gland development during puberty, pregnancy, and lactation, and explain the mechanisms that control milk production and secretion.
- Explain the physiologic basis for the effects of steroid hormone contraceptive methods.
- Describe the age-related changes in the female reproductive system, including the mechanisms responsible for these changes, throughout life from fetal development to senescence.
The principal functions of the female reproductive system are to produce the ova for sperm fertilization and to provide the appropriate conditions for embryo implantation, fetal growth and development, and birth. Endocrine regulation of the reproductive system is directed by the hypothalamic-pituitary-ovarian axis. Ovarian-derived hormones regulate the hypothalamic-pituitary-gonadal axis in a classical negative feedback pattern. Throughout the ovarian cycle, a selected follicle is stimulated to undergo growth and development, culminating in ovulation. The remnants of the follicle undergo reorganization into the corpus luteum, a temporary endocrine organ that plays a central role in preparation and maintenance of the initial stages of pregnancy. Parallel changes occur in endometrial morphology and function throughout the ovarian cycle in preparation for implantation of a fertilized ovum. Ovarian and placental hormones maintain pregnancy and prepare the breast for lactation. This chapter describes the basic principles of the neuroendocrine regulation of this hypothalamic-pituitary-ovarian axis.
The female reproductive organs include the ovaries, the uterus and fallopian tubes, and the breasts or mammary glands (Figure 9–1). Their growth, development, and function are under hormonal regulation. The ovaries store and release the ovum and produce the 2 principal female sex hormones, estrogen and progesterone. Functionally, the ovaries consist of an outer cortex layer containing different-size follicles and an inner medulla consisting of vascular connective tissue and hilar cells. The primordial follicle contains a primary oocyte surrounded by epithelial (pregranulosa) cells separated from the ovarian stroma by a basement membrane. During follicular development, the epithelial cells differentiate into granulosa cells, and a layer of cells from the ovarian stroma is transformed into theca cells. The larger, more mature follicles are filled with a transparent albuminous fluid and consist of an external fibrovascular coat, connected ...