Acknowledgment The editors wish to thank the authors for their valuable contributions to this chapter in the 5th edition. The chapter has been republished here virtually unchanged. Introduction The adrenal cortex undergoes remarkable growth and unique metamorphosis during the fetal…
Introduction The development of the hypothalamus-pituitary-adrenal (HPA) axis begins early in gestation. Corticotropin-releasing hormone (CRH) is synthesized and secreted into the hypophyseal portal circulation by the paraventricular nucleus of the hypothalamus. CRH acts on corticotroph cells in the anterior pituitary…
Acknowledgments Research work in the senior author’s (TRK) laboratory is supported in part by the National Institutes of Health (AG056046, HD081162, AG029531, AG062319, HD097202) and The Makowski Family Endowment. Introduction The pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH),…
Introduction and Background In the fully developed organism, growth hormone (GH), a 22-kDa molecule of 191 amino acids, is synthesized by acidophil cells in the anterior pituitary gland under the direction of hypothalamic GH-releasing hormone, which binds to its G…
Introduction Growth during fetal life is characterized by an early period of cell division and organogenesis, followed by a more prolonged period of growth and refinement of organ development. Growth factors are peptides or proteins that serve as key regulators…
Acknowledgment The editors wish to thank authors Adda Grimberg and Jessica Katz Kutikov for their excellent contribution to this text in the fifth edition. This chapter has been reproduced here in the sixth edition essentially unchanged. Introduction Enabled by its…
Introduction Embryology is the basis for understanding the intimate relation between structures in different organ systems, such as the nervous system and muscle, and is primordial for understanding pathogenesis in disorders of development that in the human may present as…
Acknowledgments Disclosures: The authors report no conflict of interest, financial or otherwise, concerning the material or methods used in this study or the findings specified in this paper. Funding: There were no sources of financial or material support for this…
Olfaction Perception of odorous molecules is the oldest special sense in both phylogeny and ontogeny. Olfaction is the earliest special sense in evolution; even polyps and jellyfishes, possessing only a loose neural net without a brain or even a ganglion,…
Acknowledgments Preparation of this chapter was supported by grants from the National Institute on Deafness and Other Communication Disorders (R01DC011555 and R01DC017924 [DJT], F32DC018195 [KLA], and K23DC013583 [KMU]). Early Morphology and Physiology This section reviews the course of morphologic development…