RT Book, Section A1 kibble, Jonathan D. SR Print(0) ID 1172667254 T1 Endocrine Physiology T2 The Big Picture Physiology: Medical Course & Step 1 Review, 2e YR 2020 FD 2020 PB McGraw Hill PP New York, NY SN 9781260122503 LK accessmedicine.mhmedical.com/content.aspx?aid=1172667254 RD 2024/10/06 AB A hormone is a chemical produced by the body that has a specific regulatory effect on a target cell or organ.Chemical signaling can occur in three modes (Figure 8-1).Endocrine: The hormone is carried a large distance via the blood.Paracrine: The hormone only diffuses in local extracellular fluid.Autocrine: The hormone acts at receptors on the cell that secreted it (e.g., growth factors made by cancer cells).The seven classical endocrine glands are the pituitary, adrenal, thyroid, parathyroid, pancreas, testis, and ovary (Table 8-1).Other organs also secrete hormones (e.g., hypothalamus, heart, kidney, gastrointestinal tract, liver, adipose tissue, bone).Endocrine diseases may be caused by excess or deficiency of a hormone or by defects in hormone receptors or downstream intracellular signaling.Certain neoplasms (e.g., small cell lung cancer) may secrete hormones, causing paraneoplastic syndromes.