RT Book, Section A1 Mescher, Anthony L. SR Print(0) ID 1208290128 T1 Endocrine Glands T2 Junqueira's Basic Histology: Text and Atlas, 17th Edition YR 2024 FD 2024 PB McGraw Hill PP New York, NY SN 9781264932146 LK accessmedicine.mhmedical.com/content.aspx?aid=1208290128 RD 2024/11/13 AB Secretory cells of endocrine glands release their products, signaling molecules called hormones, into neighboring vascularized compartments for uptake by capillaries and distribution throughout the body. Unlike exocrine gland secretions, hormone release does not involve secretory ducts. Most endocrine cells are typically epithelial, at least in origin, and aggregated as cords or clusters. Besides the specialized endocrine glands discussed in this chapter, many other organs specialized for other functions, such as the heart, thymus, gut, kidneys, testis, and ovaries, contain various endocrine cells (Figure 20–1). As described in earlier chapters, release of hormone-like factors also occurs in certain cells developing and functioning also as neurons, smooth and cardiac muscle fibers, leukocytes, and fibroblasts.